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HomeMy WebLinkAboutGeneral Plan Elements: Technical Information r Philip L. Boyd Deep Canyon DPP Desert Research Center qO ;e y a� Valley Studios,Hemet 0 Annual Report 1972-1973 This aerial photograph, from about 6,000 feet, was taken by Walter E. Frisbie, Hemet commercial photographer. It shows the station buildings at the 950-foot elevation near the lower left corner. Deep Canyon Creek swings sharply north below the buildings, at the toe of Sheep Mountain. The canyon continues to the right (south) upstream into the lower gorge near the upper right corner of the picture. Jeep trails and the main road are barely discernible. The Philip L. Boyd Deep Canyon Desert Research Center comprises nearly 14,000 acres of Colorado Desert floodplain and foothill canyons of the eastern slopes of the Santa Rosa Mountains about 75 miles southeast of Riverside. The nearest major community is 4 Palm Springs, about 19 miles northwest. Indio is 11 miles to the east. The center is a desert wilderness area, yet readily accessible for research purposes. Elevations range from 700 feet at the northern boundary, which is marked by a chain link fence and a locked gate, to nearly 5,000 feet on the upper slopes of Sheep Mountain to the south. Research elevations nearby are from —235 feet at the Salton Sea to 8,700 feet on Toro Peak, summit of the Santa Rosas. Administered by the University of California at Riverside, the center is a major unit in the statewide Natural Land and Water Reserves System of the university. Until the acquisition of Santa Cruz Island, it was the largest. The center provides well-equipped laboratory and living quarters for short-term or ' long-range researchers. Use of the facilities can be reserved through the center's director, in care of the Department of Biology, University of California, Riverside. 10 1. The year 1,972-1973 was a period of change for the Philip L. Boyd Deep Canyon Desert Research Center--changes in personnel, administrative responsibilities - all with the goal of increasing the center's research 40 capabilities and use through a long-range developmental program. Much of the change resulted from recommendations contained in the Lewis Report of June, 1972. This document was submitted to the chancellor by an ad hoc committee appointed by him in December, 1971. It was headed by Dr. Lowell Lewis, associatej! dean for research, college of agricultural and biological sciences. 0 Dr. Irwin P. Ting, professor of biology (plant physiology) at the University of California, Riverside, was appointed director of the center early in the year, succeeding Dr. Frank Vasek, chairman of the department of biology, who had functioned as interim director since the resignation of Dr. Rodolfo Ruibal in February, 1972. Dr. Ting is under the general administrative supervision of Vice Chancellor Van L. Perkins. Deep Canyon retains a housekeeping liaison with the biology department. Effective July 1, Lloyd Tevis resigned as associate research specialist, ending a long career with the center which actually pre-dated Deep Canyon's acquisition by the university in 1958. Tevis had served with the California Institute of Technology's desert mobile laboratory since the mid-1950s. It was located in Deep Canyon largely through the efforts of Tevis. Mr. Tevis has not announced his future research plans. He recently was elected to the newly created Rancho Mirage city council and retains his directorship in the Living Desert Association at Palm Desert. Deep Canyon has preliminary plans to publish his manuscript about desert amphibians. 10 2. Two fulltime staff members were named in February, 1973. Jan Zabriskie, a botany graduate of Pomona College, was assigned as resident researcher, working fulltime at the station. Bill Jennings, a graduate of San Diego State College and veteran Riverside County newspaperman, was assigned as principal editor, to work both at the center and at a new office in the biology department at Riverside. An agreement was reached with General Telephone Co. for the early replacement of the radio-telephone with a landline telephone. Delays in construction have resulted from engineering difficulties. The line will be installed on the poles of the Anza Electric Cooperative, which bring W electric power to Deep Canyon from the Pinyon Flats area. Through the generosity of Philip L. Boyd, a new housing unit was installed during the spring to serve the resident researcher. Known as Palo Verde Cottage, the little building was used first at Deep Well Ranch near Palm Springs in the 1930s and in recent years at Mr. Boyd's Deep Canyon Ranch as a guest house. It blends in with other structures at Deep Canyon station. Two additional travel trailers were purchased with Deep Canyon funds to provide overnight or short-stay quarters for researchers at the station `w and at the 2,700-foot elevation near Highway 74, 14 miles by road from the canyon floor. Early in February, a comprehensive news release detailing the 20- year study of Deep Canyon's resources was distributed by the campus public affairs office. It was used widely by regional newspapers and provided the basic facts for several major feature stories, a pending magazine article and at least two television sequences. �► 3. Financial implications of this long-range program will be outlined in a special section of this report. Much of the preliminary portion of this 20-year study is underway, in the nature of inventories or surveys of existing biological forms within the 13,000 acres of the Boyd center. The most ambitious of these is an entomological study primarily conducted by Mr. Saul Frommer, senior museum scientist in the UCR department of entomology. (Mr. Frommer's detailed annual report is summarized later in this report.) Mrs. Nancy Zabriskie, longtime associate with the Los Angeles State- County Arboretum, continued her plant collection, identification and classi- fication work at Deep Canyon as a volunteer. Due to a combination of timely rainfall and warm weather, the spring produced a bounty of annual plants, including what many desert oldtimers called the greatest display of wild- flowers in a half-century. Three projects under the Desert Biome portion of the U.S. International Biological Program also contributed significantly to the Deep Canyon "inventory" in the fields of succulent plants , nematodes and small mammals. Details of these individual projects are listed later in this report. Increased use of computer input, storage and retrieval is an integral part of the long-range program. Funds for this work are part of the budget expansion program now being proposed. Following are some highlights of the year in several categories. LAND ACQUISITION Better control over environmental conditions by land acquisition �r 4. continued to be a matter of major concern to Deep Canyon as to all other units of the University-wide Natural Land and Water Reserves System (NLWRS) . A lack of funds prevented additional land purchase to remove some of the checkerboard patterns of privately held sections adjacent to the U.S. Bureau of Land Management (BLM) sections now under research control by the university. Some sections have been offered for sale but at high prices. One significant plus came during the year, however. A new inter- agency committee composed of federal, state and county agencies which have concerns with the Santa Rosa Mountains desert bighorn sheep habitat was formed, primarily at the urging of the California Department of Fish and Game. Federal agencies involved include BLM and the U.S. Forest Service. Other state agencies include the California Department of Parks and Recrea- tion, the University of California and perhaps later the California Division �r of Forestry. The Riverside County Parks Department and County Planning Commission complete the list. The new committee has several objectives of interest to Deep Canyon. Primary among these are coordination in land acquisition, management and disposal, in order to prevent duplication, to improve agency cooperation and provide a common information exchange for sheep management. The anticipated announcement this fall of a major fund drive to enhance the NLWRS is also a hopeful development for Deep Canyon. PHYSICAL FACILITIES A major plant expansion program during the year included addition of a permanent dwelling for the resident researcher, Palo Verde Cottage, a longtime resort cottage used at both Deep Well Ranch and Deep Canyon Ranch 5. since before World War II by Mr. Philip L. Boyd. He moved the comfortable dwelling from Palm Desert to the Deep Canyon station at his own expense and underwrote rehabilitation costs. Two used travel trailers were added as temporary quarters for short- term researchers. One, with air-conditioning and complete kitchen facilities , was installed between the Pomona College trailer used by Dr. William Wirtz and the former Desert Mobile Laboratory trailer obtained from California Institute of Technology many years ago. The second trailer, smaller, with only desert cooling, was placed at the upper station off Highway 74 at the 2,700-foot level. It will be used by overnight research teams of three persons or less. With addition of the two trailers, the center can now accomodate upwards of eight guests in comfort and over a dozen in an emergency. Still under construction at the end of the year was a new road and gate access to the station, provided free by Ironwood Country Club, as Silver Spur Associates now call their golf-tennis condominium development just north of the center. The existing road was realigned around the eastern boundary of Ironwood's longest golf course. A second road was graded along the perim- eter of Coyote Canyon wash to a new gate opening a quarter-mile east of the present gate. When compacted for two-wheel-drive vehicles , the new road will open an undergraduate class study area outside the fence and provide an alternate route to the station buildings. RESEARCH PROGRESS The Desert Biome of the U.S. International Biological Program continued to fund three major long-range projects at Deep Canyon, although one was with- drawn from federal support at year 's end. These included the Opuntia spp 6. studies undertaken four years ago by Drs. Ting and Hyrum Johnson; the continuing desert nematode survey led by Dr. Reinhold Mankau of UCR, and Dr. Wirtz's small mammal ecological studies. The Pomona program is continuing but Dr. Wirtz no longer receives federal assistance directly. The other major continuing project is Dr. Jack Turner's desert bighorn sheep (Ovis canadensis) physiology study, now in its fifth year. He received his doctorate early in 1973 as a partial result of his work at Deep Canyon 40 and also received new financial support from the National Geographic Society. Both the insect and plant collections were expanded during the year, particularly in early spring due to a propitious combination of rainfall and ` temperature that led to an unusual growth of annual plants. The resulting wildflower display throughout the Colorado and Mohave deserts was described as the best in the past half century. Mrs. Zabriskie, aided by other volunteers, stepped up the rate of plant collection, identification and classification. Her son, Jan, continued and expanded her work to upper elevations during the early summer months. The 40 partial floristic list for the Deep Canyon Transect represented by specimens in the center's herbarium totaled 356 species by the end of the fiscal year. The total number of mounted specimens in the herbarium reached 684. 40 Duplicates are now being collected to indicate seasonal, population and individual differences for a species as well as to facilitate identification of plants for related research. A need for additional herbarium space is noted. Jan Zabriskie established three permanent plant quadrats, each 100 meters square, to determine seasonal and long-term changes , as part of the r 20-year study. Data for density, relative frequency and cover have been accumulated. Two quadrats are near the station at the 1,000-foot elevation, 7. one in Coyote Canyon, the other in Sheep Canyon. The third is at the 2,700- foot elevation near the upper site weather station near Highway 74. Zabriskie also installed three additional recording weather stations to complement the existing station near the laboratory, which also has been W expanded. Shelters at the mouth of Deep Canyon gorge and Sheep Canyon each contain rain gauges and hygrothermographs to record (on a seven-day clock) temperature and relative humidity. The upper site shelter includes a two- point thermograph for surface and subsurface temperature as well as a hygro- thermograph and rain gauge. The hygrothermeter, pyrheliometer and rain gauge at the station site have been supplemented by a dew meter , microbarograph, evaporimeter and a two-point thermograph, all recording with seven-day clock mechanisms. The result, for the first time, is accurate and relatively complete weather information for three separate locations in the center. one. At the fiscal year's end, Mrs. Zabriskie was completing a cross-index file for the herbarium; reorganizing the herbarium, with labeled family and -10 genus folders , and continuing the collection of plants from the transmontane slopes of the San Jacinto and Santa Rosa mountains. Progress reports for the three Desert Biome-IBP projects are on file W at the Deep Canyon office, along with copies of Dr. Turner's dissertation and Saul Frommer's annual entomological collection report. Some copies of these documents are available on request. r As an additional zoological project, Dr. Turner completed an environ- mental study for Palm Springs Atajo, a large-scale residential and recreational development in the Haystack-Asbestos mountains section of the Santa Rosas. He was assisted during the summer by Peg Merritt, a UCR undergraduate zoology student, primarily funded by the Atajo developers. 8. Dr. Turner is now on the zoology faculty at the University of Wyoming, Laramie, but continues to monitor the bighorn study with the assistance of Karen Fowler, director of Living Desert Reserve near the center at Palm Desert. PUBLICATIONS-PUBLIC RELATIONS Selected, special-interest groups continued to visit Deep Canyon during the year, on invitation only. The pace of newspaper, magazine and television coverage continued to increase, highlighted by the birth of a bighorn sheep ram lamb on Easter Sunday. Mr. Jennings prepared the manuscript of Ants of Deep Canyon, by Drs. G. C. and Jeanette Wheeler of the University of Nevada Desert Research Institute. It was expected to be off the press by mid-fall, as the second book in an anticipated series of science-popular books on the center's resources and research. The first was Mark Ryan's Mammals of Deep Canyon, published by the Palm Springs Desert Museum in 1968. Subsequent publications under consideration include Lloyd Tevis ' Paradoxes of the Desert: Toad, Frog and Salamander. This is not expected to be a full length book due to the limited nature of its subject matter. Also in preliminary stages are a comprehensive history of Deep Canyon, requested by Chancellor Ivan Hinderaker, and a general-interest book with the tentative title: Deep Canyon, A Desert Wilderness for Science. A New York writer also is attempting to "sell" a desert environmental 40 book to Time-Life Books, with Deep Canyon as a central point for his theme. In addition, Dr. Turner anticipates a manuscript for National Geographic Magazine at the conclusion of his long-range sheep study. The major publicity development during the year was preparation of a 9. five-minute television tape show for worldwide distribution by the U.S. Information Agency. Attached are summary reports of publications/scientific paper presenta- tions ; analysis of visitor registrations; research projects, and a partial listing of future objectives and financial requirements. 10. RESEARCH PROJECTS (Number after description is estimate of man-days involved.) Desert Biome--U.S. International Biological Program Mankau, R. (and others) . The biology of nematodes in desert ecosystems. UCR. 12 Ting, I. P. (and others). Gas exchange and productivity for 0 untia spp. UCR. 150 Wirtz, William 0. II. Ecology of ground squirrels and kangaroo rats. Pomona College. 80 Frommer, Saul. (and others) . Continuing insect survey. UCR. 25 * + Tabet, Ali. Phenological study of bombyliid populations in Deep Canyon.UCR. 60 Turner, Jack (and others). Continuing physiological study of desert bighorn sheep. UCR. 60 Skjold, H. E. Water hydrology of Deep Canyon. U.S. Geological Survey 6 Zabriskie, Nancy (and others). Collection and classification of plants; revision of floristic list; reorganization of herbarium, files. UCR. 40 * + Lawton, Harry and Phil Wilke. Aboriginal agriculture. UCR. 6 Jones, Ronald. Water turnover study in black-throated sparrow. UCR. 4 Walsberg, Glenn. Ecological study of Phainopepla nitens. UCLA, 5 Krout, Douglas. Non-symbiotic bacterial nitrogen fixation in desert soils. CSU-SD. 9 Tevis, Lloyd. Desert amphibians (preparatory for publication) UCR. 36 * Kitasako, John. Biological survey, Palm Hills annexation area. UCR . 6 Zabriskie, Jan. Plant collection, seed collection in several transects in Deep Canyon area. 25 * * Research financed totally, or in part by Deep Canyon funds. + This does not include many man-hours spent at UCR on this project. 11. SUMMARIES OF MAJOR RESEARCH PROJECTS DESERT BIOME Gas Exchange and Productivity for Opuntia Spp. Irwin P. Ting, Project Leader H. B. Johnson, T. A. Yonkers and S. R. Szarek Annual rates of productivity have decreased for the cholla cactus, 0. acanthocarpa and 0. biglovii. Such results appear to be directly related to a 19-month period of very arid conditions at Deep Canyon. (Editor's note: This report was prepared prior to the spring of 1973.) During periods of dry, arid conditions stomata remained closed throughout the 24-hour day. Cuticular resistances exceeded 600 sec/cm for the three Opuntia species, such that 14CO2 uptake cannot be measured. The day/night fluctuation in stem tissue acidity is low and quite predictable. This study began at Deep Canyon in 1971 and is continuing into the r 1973-1974 fiscal year. Deep Canyon was chosen for the research site because of the comparative abundance of Opuntia Spp. in the research station and adjoining areas of the Colorado Desert. The three species under study are 0. acanthocarpa, 0. biglovii and 0. basilaris. The Deep Canyon study complements the work of Duncan Patten at Arizona State University, Tempe. During the current year, the Deep Canyon study will include further investigation of the responses of the three Opuntia species to environmental parameters. 12. SUMMARIES OF RESEARCH PROJECTS (Continued) DESERT BIOME Natural Activity in Patterns and Thermal Experience in Dipodomys merriami W. 0. Wirtz, II, Project Leader and D. V. Brown Objectives of this study (which began in 1970) were to document by biotelemetric techniques the natural activity patterns and thermal experiences of Dipodomys merriami (Merriam kangaroo rat) in the Colorado Desert, a major division of the Sonoran Desert. A series of technical difficulties hampered Dr. Wirtz's efforts to perfect functional telemetric equipment. A year's demographic data on the species and associated Deep Canyon rodents was obtained, along with corollary measurements of temperature in burrows, surface and air conditions. Activity patterns of kangaroo rats under simulated desert summer and winter conditions were examined in the laboratory at Pomona. Early in 1970 the project leader began working with General Dynamics, at Pomona, on the design of biotelemetric techniques for monitoring small rodent forms. By late 1971 functional models were "breadboarded." Despite this good start no transmitters were available for the project by 1972. Work during the fiscal year, therefore, was somewhat hampered. Dr. Wirtz began work in December, 1972, on an alternate telemetry system. During the current year he plans to refine the use of this equipment for securing necessary information on natural activity patterns and thermal experience. �w 1W 13. SUR&I�LRIES OF RESEARCH PROJECTS (Continued) 40 uCR- l� tional Geographic Society Dntinuing physiological studies of Desert Bighorn Sheep (Ovis canadensis) This study is conducted by Dr. Jack Turner, now a zoology instructor at the University of Wyoming, Laramie. He began his field work at Deep Canyon and in surrounding sheep habitat in the Santa Hosa P'lountains as a graduate student in 1969 and continues his project with student help this year, although 1-,is duties at Laramie preclude other than summer and short-term field studies personally. To date, Dr. Turner's primary publication has been his own dissertation, entitled "Water, Energy and Electrolyte 3alance in the :)esert 3iN,horn Sheep, Ovis canadensis." He also is preparing manuscript data for consideration by National Geographic Society for publication in its worldwide monthly magazine, as a consideration of the grant. The desert bighorn, subspecies Ovis canadensis cre_nnobates Elliot, is the largest naturally occuring mammal in the Colorado Desert. Dr. iarner's studies, on calotive animals at Living; Desert reserve ne=.r the Deep Canton station, and on free ranging animals in the Santa itiosa i°ange, involve monitoring physiological and behavioral functions with radio collars, remote sensor telemetry gear and more conventional 1iboratory and visual methods. He works in full cooperation with the State Department of Fish and name, which has had total responsibility for this protected species under state law since 1873. Without the department's express consent, and enabling state law, Dr. Turner's work would not be ooss:ible. 14. SUMMARIES OF RESEARCH PROJECTS (Continued) UCR-Department of Entomology Continuing entomological survey, collection and Classification in the Deep Canyon Transect Saul Frommer, Project Leader The entomological survey for the Philip L. Boyd Deep Canyon Desert Research Center has been underway since the mid-1960s, first under the direction of Dr. Evert I. Schlinger (now on the faculty of UC, Berkeley) and for the past several years led by Saul Frommer, senior museum scientist for the department. (Because of the detailed nature of Mr. Frommer's report, it is not included as an appendix to this annual statement but is available on W request.) During the year, Mr. Frommer continued the preparation, identification and storage of heretofore collected arthropod materials; gathered additional materials , particularly plentiful because of the aforementioned spring conditions of rainfall, plant growth and temperatures. He continued the development of a data storage and retreival program for the Deep Canyon arthrop fauna. Specific research was conducted on the dipterous families Bombyliidae, Chamaemyiidae and Chironomidae. He was assisted in many ways by Dr. John Pinto, Dr. Peter Rauch (at Berkeley) , Ali Tabet (UCR graduate student) and Phil McNally (undergraduate) . With the help of Lloyd Tevis, Mr. Frommer also conducted a site survey of the lower Deep Canyon gorge, from the Zero marker to Thunderbird pool. 40 15. PUBLICATIONS (Including papers delivered at seminars, symposiums, etc.) Lynch, Timothy, Rodolfo Ruibal and Lloyd Tevis. 1973. Birds of a cattle feedlot in the Southern California desert. California Agriculture, AV 27(3) : 4-6. Oechel, W. C. , B. R. Strain and W. R. Odening. 1972. Photosynthetic rates of a desert shrub, Larrea divaricata Cay. , under field conditions. Photosynthetica 6(2) : 183-188. Oechel, W. C. , B. R. Strain and W. R. Odening. 1972. Tissue water potential photosynthesis, 14C-labeled photosythate utilization and growth in the desert shrub, Larrea divaricata Cay. Ecological Monographs 42:127-142. Spring 1972. Szarek, Stan R. , Hyrum B. Johnson and I. P. Ting, 1973. Drought adaptation in 0_puntia basilaris: significance of recycling carbon through crassulacean acid metabolism. Plant Physiology (in press). Ting, I. P. Carbon metabolism in plants. What's New in Plant Physiology 5(3) : 4 pp. 1973. Ting, I. P. , Physiological adaptation to water stress in desert plants. Paper presented at Physiological Adaptation Symposium, American Institute of Biological Science meeting, June, 1973. (to be published). Ting, I. P. , Hyrum B. Johnson and Stan R. Szarek. 1972. Net CO2 fixation in crassulacean acid metabolism plants. Proceedings of Southern Section, American Society of Plant Physiologists/Cotton, Inc. :26-53. V 16. PUBLICATIONS (Continued) Ting, I. P. , Hyrum Johnson and Stan R. Szarek. 1973. Gas exchange and productivity for 0 up ntia spp. Paper presented at International Biological Program Conference, Wales, April, 1973. (to be published in proceedings). Turner, J. C. 1972. Water, energy and electrolyte balance in desert bighorn sheep Ovis canadensis) . Ph.D. Thesis, University of California, Riverside. 132 p. �w 4w 17. FUTURE OBJECTIVES---FINANCIAL REQUIREMENTS �w Students of previous annual reports for the Philip L. Boyd Deep Canyon Desert Research Center will recall a number of recurring concerns expressed by the authors, who generally were identified as chairmen of the control committee within the department of biology. Appointment of Deep Canyon's first independent director (who reports 40 to the vice chancellor directly) has not changed any of these concerns, although it permits perhaps a better articulation and expression of them. First, there remains the primary problem of land acquisition in order s to protect the fragile environment, particularly pressing in 1973 due to increased private land speculation and/or development in the previously thought inaccessible Santa Rosa Mountains. The recommendation remains the same as in previous years--acquisition of inholding privately-owned land sections , particularly the three immediately south of the Deep Canyon station laboratory. A permanent endowment fund to support expanding research remains a major objective. Expanded budget funds to support both increased research and to provide additional support staff personnel and facilities needed to provide a base for such research. In that line, the needs include housing, improved domestic water retrieval and storage; additional jeep roads and trails, particularly upper elevation areas; a third laboratory and accompanying storage space; additional utilities, including electricity, telephone, natural gas or propane, sewerage and parking facilities. r 18. To accomplish the 20-year study plan announced during the fiscal year, these things are mandatory, along with computer input, storage and retrieval capacity to serve researchers anywhere in the world who wish to use Deep Canyon's store of knowledge, either by computer or as preliminary informa- tion for their future research studies. A Preliminary and tentative budget expansion proposal is being prepared for submission in order that Deep Canyon's needs for future growth can be met. The budget request is being prepared with care so as not to handicap or inhibit any requests for on-campus research facilities at Riverside. The staff is continuing to explore ways and means of securing additional, supplemental funding from sources outside the university, to support current and contemplated future research discussed in the next section of this report. 19. PROPOSED AND/OR ANTICIPATED MAJOR PROGRAMS The director proposes a seminar-symposium series on an alternate-year basis to cover important and current aspects of desert biology. A proposal for the first is now being prepared. A joint Australian-U.S. comparative desert program is now in the proposal stage, both at UCR and at the Australian National University in 4V Canberra. The physiology and biochemistry of desert succulents native to the American deserts and naturalized in much of Australia will be studied. A cooperative graduate-student program between Deep Canyon and the University of Coahuila, Mexico, has been proposed through the Dry-Lands Research Institute, UCR. It would emphasize greater use of cactus as animal fodder and human food in the southern republic. Also proposed is a computer storage-retrieval plan for phenological data in which seasonal changes in biomass, species , etc. , will be followed. The Deep Canyon "five-foot shelf" of books containing practical and useful information about Deep Canyon, and the Colorado Desert in general, is underway. Desert biology will be the primary emphasis of this series, which will continue the work of Mammals of Deep Canyon, by R. Mark Ryan (1969) , and Ants of Deep Canyon, by G. C. and Jeannette Wheeler (1973). These will be written in semi-popular style, in language suitable for use both by biologists and the lay public. Cooperative programs are being considered with Southern California land developers, designed to study the impact of development of desert land on ecosystems. A series of limited field courses for graduate students in desert �r 20. biology is contemplated to enhance existing programs and to provide greater use of Deep Canyon without disturbing its relatively pristine wilderness status. AV 21. VISITORS Use of the Deep Canyon center continued to increase during the fiscal year, although the present sign-in/sign-out registration procedure at the gate is admittedly an imperfect method of determining this activity. For example, sign-ins totaled 806 during the year, up from 616 in the 1971-1972 fiscal year, and only slightly below the all-time "record" of 813 logged in 1970-1971. Inasmuch as some visitors do not sign in and others are listed only as "and party" by the principal visitors the system is not accurate. �r Another example, more than 60 man-days were involved in relocation and remodeling of Palo Verde Cottage as the resident researchers quarters. Some of the workers signed in daily; others did not. Some research projects involve visits to the upper elevations only and no registration is noted. Many short-term projects particularly are not logged at all. Nevertheless, for the benefit of those who measure success by numbers , here are two tables concerning visitation: TABLE 1--Total number of visitors by months " July 14 August 27 September 39 October 29 November 71 December 73 January 75 February 113 March 135 April 123 May 59 June 40 2 2. TABLE 2 Origin of Visitors University of California--Riverside, Los Angeles, Berkeley, Santa Barbara, Davis, San Diego and Irvine. California State Universities--San Diego and Fullerton Other State Universities--Michigan, Utah State at Logan, Illinois, Nevada at Reno, Wyoming. Other U.S. Universities--Rutgers and Columbia. Pomona College. Foreign Universities--Paris, France; Moscow, USSRi Lund, Sweden; Oxford, England. Related Institutions--California Institute of Technology, Desert Research r Institute at Reno, Los Angeles State-County Arboretum, Descanso Gardens, Living Desert Reserve. Conservation Groups--Nature Conservancy, Desert Protective Council. Federal Agencies--Bureau of Land Management, Forest Service, Weather Service, Geologic Survey, Fish and Wildlife Service. State Agencies--Department of Fish and Game, Department of Parks and 0 Recreation, Division of Forestry. County Agencies--Parks Department, Sheriff's Department, Parks Advisory Commission, Coachella Valley County Water District. Other Agencies--Agua Caliente Indian Tribal Council. Museums--Malki of Morongo Indian Reservation, Desert Museum of Palm Springs. Distinguished University Guests--President Charles Hitch, Regent Edward Carter, Chancellor Ivan Hinderaker, Vice Chancellor James Sullivan, Dr. Mildred Matthias. Communications Media--U.S. Information Agency, National Broadcasting Co. , r Los Angeles Times, Christian Science Monitor, Time-Life Books. Idyllwild Town Crier. 2 3. TABLE 2A Distinguished Visitors from the University of California W President Charles Hitch Regent Edward Carter Chancellor Ivan Hinderaker 4 Vice Chancellor James Sullivan Dr. Mildred Mathias, Los Angeles, Natural Land and Water Reserves System Dean W. M. Dugger �r Dr. E. Barnett, Regent's Lecturer Visiting Professors from foreign universities Otto Lange, West Germany Orlando Quieroz, Paris, France Ms. Gunnar Erlandson, Lund University, Sweden 4W 24. STAFF 11EMBERS ame Working Title Irwin F. Ting Director Bill Jennings Editor-Liaison Officer Jan Zabriskie Resident Biologist Karen Fowler Volunteer-Mammalogist Nancy Zabriskie Volunteer-Museum Scientist Mrs. Fowler is the fulltime director-administrator of Living Desert) The staff wishes to thank Mr. Philip L. Boyd, ex-Regent of the University of California for his unfailing interest and full support. the administrative staff of the Department of Biology, University of California, Riverside, also provides unflagging assistance and support for the center in innumerable ways, without which the small staff of the center would not be able to function. Particular research and academic support has been provided unselfishly by Saul Frommer, Oscar Clarke and Hyrum.Johnson. 'r W SOUTHERN CALIFORNIA ------------------------- Los Angeles a Riverside • PalmeSprings *Deep Canyon N Palm Springs (11miles) Palm Desert Indio -• (7miles) a, 0 0 AV a 74 1Ae,unpaved i �.._-_. Carriage Trail r i i LOCKED GATE i! Hemet Deep Canyon Idyllwild Desert Research Area e�ir THE PHILIP L. BOYD DEEP CANYON DESERT RESEARCH CENTER ANNUAL REPORT 1972-1973 UNIVRSITY OF CALIFORNIA RIVERSIDE 1. The year 1972-1973 was a period of change for the Philip L. Boyd Deep Canyon Desert Research Center--changes in personnel, administrative responsibilities - all with the goal of increasing the center's research capabilities and use through a long-range developmental program. Much of the change resulted from recommendations contained in the Lewis Report of June, 1972. This document was submitted to the chancellor by an ad hoc committee appointed by him in December, 1971. It was headed by Dr. Lowell Lewis, associated dean for research, college of agricultural and biological sciences. Dr. Irwin P. Ting, professor of biology (plant physiology) at the University of California, Riverside, was appointed director of the center early in the year, succeeding Dr. Frank Vasek, chairman of the department of biology, who had functioned as interim director since the resignation of Dr. Rodolfo Ruibal in February, 1972. Dr. Ting is under the general administrative supervision of Vice Chancellor Van L. Perkins. Deep Canyon retains a housekeeping liaison with the biology department. Effective July 1, Lloyd Tevis resigned as associate research specialist, ending a long career with the center which actually pre-dated Deep Canyon's acquisition by the university in 1958. Tevis had served with the California Institute of Technology's desert mobile laboratory since the mid-1950s. It was located in Deep Canyon largely through the efforts of Tevis. Mr. Tevis has not announced his future research plans. He recently was elected to the newly created Rancho Mirage city council and retains his directorship in the Living Desert Association at Palm Desert. Deep Canyon has preliminary plans to publish his manuscript about desert amphibians. 2. Two fulltime staff members were named in February, 1973. Jan Zabriskie, a botany graduate of Pomona College, was assigned as resident researcher, working fulltime at the station. Bill Jennings, a graduate of San Diego State College and veteran Riverside County newspaperman, was assigned as principal editor, to work both at the center and at a new office in the biology department at Riverside. An agreement was reached with General Telephone Co. for the early replacement of the radio-telephone with a landline telephone. Delays in construction have resulted from engineering difficulties. The line will be installed on the poles of the Anza Electric Cooperative, which bring electric power to Deep Canyon from the Pinyon Flats area. Through the generosity of Philip L. Boyd, a new housing unit was installed during the spring to serve the resident researcher. Known as Palo Verde Cottage, the little building was used first at Deep Well Ranch near Palm Springs in the 1930s and in recent years at Mr. Boyd's Deep Canyon Ranch as a guest house. It blends in with other structures at Deep Canyon station. Two additional travel trailers were purchased with Deep Canyon funds to provide overnight or short-stay quarters for researchers at the station and at the 2,700-foot elevation near Highway 74, 14 miles by road from the canyon floor. Early in February, a comprehensive news release detailing the 20- year study of Deep Canyon's resources was distributed by the campus public affairs office. It was used widely by regional newspapers and provided the basic facts for several major feature stories, a pending magazine article and at least two television sequences. 3. Financial implications of this long-range program will be outlined in a special section of this report. Much of the preliminary portion of this 20-year study is underway, in the nature of inventories or surveys of existing biological forms within the 13,000 acres of the Boyd center. The most ambitious of these is an entomological study primarily conducted by Mr. Saul Frommer, senior museum scientist in the UCR department of entomology. (Mr. Frommer's detailed annual report is summarized later in this report.) Mrs, Nancy Zabriskie, longtime associate with the Los Angeles State- County Arboretum, continued her plant collection, identification and classi- fication work at Deep Canyon as a volunteer. Due to a combination of timely rainfall and warm weather, the spring produced a bounty of annual plants, including what many desert oldtimers called the greatest display of wild- flowers in a half-century. Three projects under the Desert Biome portion of the U.S . International Biological Program also contributed significantly to the Deep Canyon "inventory" in the fields of succulent plants , nematodes and small mammals. Details of these individual projects are listed later in this report. Increased use of computer input, storage and retrieval is an integral part of the long-range program. Funds for this work are part of the budget expansion program now being proposed. Following are some highlights of the year in several categories. LAND ACQUISITION Better control over environmental conditions by land acquisition 4. continued to be a matter of major concern to Deep Canyon as to all other units of the University-wide Natural Land and Water Reserves System (NLWRS) . A lack of funds prevented additional land purchase to remove some of the checkerboard patterns of privately held sections adjacent to the U.S. Bureau of Land Management (BLM) sections now under research control by the university. Some sections have been offered for sale but at high prices. One significant plus came during the year, however. A new inter- agency committee composed of federal, state and county agencies which have concerns with the Santa Rosa Mountains desert bighorn sheep habitat was formed, primarily at the urging of the California Department of Fish and Game. Federal agencies involved include BLM and the U.S. Forest Service. Other state agencies include the California Department of Parks and Recrea- tion, the University of California and perhaps later the California Division of Forestry. The Riverside County Parks Department and County Planning Commission complete the list. The new committee has several objectives of interest to Deep Canyon. Primary among these are coordination in land acquisition, management and disposal, in order to prevent duplication, to improve agency cooperation and provide a common information exchange for sheep management. The anticipated announcement this fall of a major fund drive to enhance the NLWRS is also a hopeful development for Deep Canyon. PHYSICAL FACILITIES A major plant expansion program during the year included addition of a permanent dwelling for the resident researcher, Palo Verde Cottage, a longtime resort cottage used at both Deep Well Ranch and Deep Canyon Ranch 5. since before World War II by Mr. Philip L. Boyd. He moved the comfortable dwelling from Palm Desert to the Deep Canyon station at his own expense and underwrote rehabilitation costs. Two used travel trailers were added as temporary quarters for short- term researchers. One, with air-conditioning and complete kitchen facilities , was installed between the Pomona College trailer used by Dr. William Wirtz and the former Desert Mobile Laboratory trailer obtained from California Institute of Technology many years ago. The second trailer, smaller, with only desert cooling, was placed at the upper station off Highway 74 at the 2,700-foot level. It will be used by overnight research teams of three persons or less. With addition of the two trailers, the center can now accomodate upwards of eight guests in comfort and over a dozen in an emergency. Still under construction at the end of the year was a new road and gate access to the station, provided free by Ironwood Country Club, as Silver Spur Associates now call their golf-tennis condominium development just north of the center. The existing road was realigned around the eastern boundary of Ironwood's longest golf course. A second road was graded along the perim- eter of Coyote Canyon wash to a new gate opening a quarter-mile east of the present gate. When compacted for two-wheel-drive vehicles, the new road will open an undergraduate class study area outside the fence and provide an alternate route to the station buildings. RESEARCH PROGRESS The Desert Biome of the U.S . International Biological Program continued to fund three major long-range projects at Deep Canyon, although one was with- drawn from federal support at year 's end. These included the Opuntia spp 6. studies undertaken four years ago by Drs. Ting and Hyrum Johnson; the continuing desert nematode survey led by Dr. Reinhold Mankau of UCR, and Dr. Wirtz's small mammal ecological studies. The Pomona program is continuing but Dr. Wirtz no longer receives federal assistance directly. The other major continuing project is Dr. Jack Turner's desert bighorn sheep (Ovis canadensis) physiology study, now in its fifth year. He received his doctorate early in 1973 as a partial result of his work at Deep Canyon and also received new financial support from the National Geographic Society. Both the insect and plant collections were expanded during the year, particularly in early spring due to a propitious combination of rainfall and temperature that led to an unusual growth of annual plants. The resulting wildflower display throughout the Colorado and Mohave deserts was described as the best in the past half century. Mrs. Zabriskie, aided by other volunteers, stepped up the rate of plant collection, identification and classification. Her son, Jan, continued and expanded her work to upper elevations during the early summer months. The partial floristic list for the Deep Canyon Transect represented by specimens in the center's herbarium totaled 356 species by the end of the fiscal year. The total number of mounted specimens in the herbarium reached 684. Duplicates are now being collected to indicate seasonal, population and individual differences for a species as well as to facilitate identification of plants for related research. A need for additional herbarium space is noted. Jan Zabriskie established three permanent plant quadrats, each 100 meters square, to determine seasonal and long-term changes , as part of the 20-year study. Data for density, relative frequency and cover have been accumulated. Two quadrats are near the station at the 1,000-foot elevation, 7. one in Coyote Canyon, the other in Sheep Canyon. The third is at the 2,700- foot elevation near the upper site weather station near Highway 74. Zabriskie also installed three additional recording weather stations to complement the existing station near the laboratory, which also has been expanded. Shelters at the mouth of Deep Canyon gorge and Sheep Canyon each contain rain gauges and hygrothermographs to record (on a seven-day clock) temperature and relative humidity. The upper site shelter includes a two- point thermograph for surface and subsurface temperature as well as a hygro- thermograph and rain gauge. The hygrothermeter, pyrheliometer and rain gauge at the station site have been supplemented by a dew meter, microbarograph, evaporimeter and a two-point thermograph, all recording with seven-day clock mechanisms. The result, for the first time, is accurate and relatively complete weather information for three separate locations in the center. one. At the fiscal year's end, Mrs. Zabriskie was completing a cross-index file for the herbarium; reorganizing the herbarium, with labeled family and genus folders , and continuing the collection of plants from the transmontane slopes of the San Jacinto and Santa Rosa mountains. Progress reports for the three Desert Biome-IBP projects are on file at the Deep Canyon office, along with copies of Dr. Turner's dissertation and Saul Frommer's annual entomological collection report. Some copies of these documents are available on request. As an additional zoological project, Dr. Turner completed an environ- mental study for Palm Springs Atajo, a large-scale residential and recreational development in the Haystack-Asbestos mountains section of the Santa Rosas. He was assisted during the summer by Peg Merritt, a UCR undergraduate zoology student, primarily funded by the Atajo developers. 8. Dr. Turner is now on the zoology faculty at the University of Wyoming, Laramie, but continues to monitor the bighorn study with the assistance of Karen Fowler, director of Living Desert Reserve near the center at Palm Desert. PUBLICATIONS-PUBLIC RELATIONS Selected, special-interest groups continued to visit Deep Canyon during the year, on invitation only. The pace of newspaper, magazine and television coverage continued to increase, highlighted by the birth of a bighorn sheep ram lamb on Easter Sunday. Mr. Jennings prepared the manuscript of Ants of Deep Canyon, by Drs. G. C. and Jeanette Wheeler of the University of Nevada Desert Research Institute. It was expected to be off the press by mid-fall, as the second book in an anticipated series of science-popular books on the center's resources and research. The first was Mark Ryan's Mammals of Deep Canyon, published by the Palm Springs Desert Museum in 1968. Subsequent publications under consideration include Lloyd Tevis ' Paradoxes of the Desert: Toad, Frog and Salamander. This is not expected to be a full length book due to the limited nature of its subject matter. Also in preliminary stages are a comprehensive history of Deep Canyon, requested by Chancellor Ivan Hinderaker, and a general-interest book with the tentative title: Deep Canyon, A Desert Wilderness for Science. A New York writer also is attempting to "sell" a desert environmental book to Time-Life Books, with Deep Canyon as a central point for his theme. In addition, Dr. Turner anticipates a manuscript for National Geographic Magazine at the conclusion of his long-range sheep study. The major publicity development during the year was preparation of a 9. five-minute television tape show for worldwide distribution by the U.S. Information Agency. Attached are summary reports of publications/scientific paper presenta- tions ; analysis of visitor registrations; research projects, and a partial listing of future objectives and financial requirements. 10. RESEARCH PROJECTS (Number after description is estimate of man-days involved.) Desert Biome--U.S . International Biological Program Mankau, R. (and others) . The biology of nematodes in desert ecosystems. UCR. 12 Ting, I. P. (and others) . Gas exchange and productivity for Opuntia spp. UCR. 150 Wirtz, William 0. II. Ecology of ground squirrels and kangaroo rats. Pomona College. 80 Frommer, Saul. (and others) . Continuing insect survey. UCR. 25 * + Tabet, Ali. Phenological study of bombyliid populations in Deep Canyon.UCR. 60 Turner, Jack (and others). Continuing physiological study of desert bighorn sheep. UCR. 60 * Skjold, H. E. Water hydrology of Deep Canyon. U.S . Geological Survey 6 Zabriskie, Nancy (and others) . Collection and classification of plants ; revision of floristic list; reorganization of herbarium, files. UCR. 40 * + Lawton, Harry and Phil Wilke. Aboriginal agriculture. UCR. 6 Jones, Ronald. Water turnover study in black-throated sparrow. UCR. 4 Walsberg, Glenn. Ecological study of Phainopepla nitens. UCLA, 5 Krout, Douglas. Non-symbiotic bacterial nitrogen fixation in desert soils. CSU-SD. 9 Tevis, Lloyd. Desert amphibians (preparatory for publication) UCR. 36 Kitasako, John. Biological survey, Palm Hills annexation area. UCR . 6 Zabriskie, Jan. Plant collection, seed collection in several transects in Deep Canyon area. 25 * Research financed totally, or in part by Deep Canyon funds. + This does not include many man-hours spent at UCR on this project. 11. SUMMARIES OF MAJOR RESEARCH PROJECTS DESERT BIOME Gas Exchange and Productivity for Opuntia Spp. Irwin P. Ting, Project Leader H. B. Johnson, T. A. Yonkers and S. R. Szarek Annual rates of productivity have decreased for the cholla cactus, 0. acanthocarpa and 0. biglovii. Such results appear to be directly related to a 19-month period of very arid conditions at Deep Canyon. (Editor's note: This report was prepared prior to the spring of 1973.) During periods of dry, arid conditions stomata remained closed throughout the 24-hour day. Cuticular resistances exceeded 600 sec/cm for the three Opuntia species, such that 14CO2 uptake cannot be measured. The day/night fluctuation in stem tissue acidity is low and quite predictable. This study began at Deep Canyon in 1971 and is continuing into the 1973-1974 fiscal year. Deep Canyon was chosen for the research site because of the comparative abundance of Opuntia Spp. in the research station and adjoining areas of the Colorado Desert. The three species under study are 0. acanthocarpa, 0. biglovii and 0. basilaris. The Deep Canyon study complements the work of Duncan Patten at Arizona State University, Tempe. During the current year, the Deep Canyon study will include further investigation of the responses of the three Opuntia species to environmental parameters. 12. SUMMARIES OF RESEARCH PROJECTS (Continued) DESERT BIOME Natural Activity in Patterns and Thermal Experience in Dipodomys merriami W. 0. Wirtz, II, Project Leader and D. V. Brown Objectives of this study (which began in 1970) were to document by biotelemetric techniques the natural activity patterns and thermal experiences of Dipodomys merriami (Merriam kangaroo rat) in the Colorado Desert, a major division of the Sonoran Desert. A series of technical difficulties hampered Dr. Wirtz's efforts to perfect functional telemetric equipment. A year's demographic data on the species and associated Deep Canyon rodents was obtained, along with corollary measurements of temperature in burrows, surface and air conditions. Activity patterns of kangaroo rats under simulated desert summer and winter conditions were examined in the laboratory at Pomona. Early in 1970 the project leader began working with General Dynamics , at Pomona, on the design of biotelemetric techniques for monitoring small rodent forms. By late 1971 functional models were "breadboarded." Despite this good start no transmitters were available for the project by 1972. Work during the fiscal year, therefore, was somewhat hampered. Dr. Wirtz began work in December, 1972, on an alternate telemetry system. During the current year he plans to refine the use of this equipment for securing necessary information on natural activity patterns and thermal experience. 13. SUPE,i`,RTES OF RESEARCH PROJECTS (Continued) UCR- 'Rational Geographic Society Continuing physiological studies of Desert Bighorn Sheep (Ovis canadensis) This study is conducted by Dr. Jack Turner, now a zoology instructor at the University of Wyoming, Laramie. He began his field work at Deep Canyon and in surrounding sheep habitat in the Santa Rosa Mountains as a graduate student in 1969 and continues his project with student help this ,year, although his duties at Laramie preclude other than summer and short-term field studies personally. To date, Dr. Turner's primary publication has been his own dissertation, entitled "`dater, Energy and Electrolyte Balance in the Desert Bighorn Sheep, Ovis canadensis." He also is preparing manuscript data for consideration by National Geographic Society for publication in its worldwide monthly magazine, as a consideration of the grant. The desert bighorn, subspecies Ovis canadensis cremnobates Elliot, is the largest naturally occuring mammal in the Colorado Desert. Dr. Turner's studies, on captive animals at Living Desert reserve ne--.r the Deep Canyon station, and on free ranging animals in the Santa Rosa range, involve monitoring physiological and behavioral functions with radio collars, remote sensor telemetry gear and more conventional laboratory and visual methods. He works in full cooperation with the State Department of Fish and Game, which has had total responsibility for this protected species under state law since 1873• Without the department's express consent, and enabling state law, Dr. Turner's work would not be possible. 14. SUMMARIES OF RESEARCH PROJECTS (Continued) UCR-Department of Entomology Continuing entomological survey, collection and Classification in the Deep Canyon Transect Saul Frommer, Project Leader The entomological survey for the Philip L. Boyd Deep Canyon Desert Research Center has been underway since the mid-1.960s, first under the direction of Dr. Evert I. Schlinger (now on the faculty of UC, Berkeley) and for the past several years led by Saul Frommer, senior museum scientist for the department. (Because of the detailed nature of Mr. Frommer's report, it is not included as an appendix to this annual statement but is available on request.) During the year, Mr. Frommer continued the preparation, identification and storage of heretofore collected arthropod materials; gathered additional materials, particularly plentiful because of the aforementioned spring conditions of rainfall, plant growth and temperatures. He continued the development of a data storage and retreival program for the Deep Canyon arthrop fauna. Specific research was conducted on the dipterous families Bombyliidae, Chamaemyiidae and Chironomidae. He was assisted in many ways by Dr. John Pinto, Dr. Peter Rauch (at Berkeley) , Ali Tabet (UCR graduate student) and Phil McNally (undergraduate) . With the help of Lloyd Tevis, Mr. Frommer also conducted a site survey of the lower Deep Canyon gorge, from the Zero marker to Thunderbird pool. 15. PUBLICATIONS (Including papers delivered at seminars, symposiums, etc.) Lynch, Timothy, Rodolfo Ruibal and Lloyd Tevis. 1973. Birds of a cattle feedlot in the Southern California desert. California Agriculture, 27(3) : 4-6. Oechel, W. C. , B. R. Strain and W. R. Odening. 1972. Photosynthetic rates of a desert shrub, Larrea divaricata Cay. , under field conditions. Photosynthetica 6(2) : 183-188. Oechel, W. C. , B. R. Strain and W. R. Odening. 1972. Tissue water potential photosynthesis, 14C-labeled photosythate utilization and growth in the desert shrub, Larrea divaricata Cay. Ecological Monographs 42:127-142. Spring 1972. Szarek, Stan R. , Hyrum B. Johnson and I. P. Ting, 1973. Drought adaptation in 0 untia basilaris : significance of recycling carbon through crassulacean acid metabolism. Plant Physiology (in press). Ting, I. P. Carbon metabolism in plants. What's New in Plant Physiology 5(3) : 4 pp. 1973. Ting, I. P. , Physiological adaptation to water stress in desert plants. Paper presented at Physiological Adaptation Symposium, American Institute of Biological Science meeting, June, 1973. (to be published). Ting, I. P. , Hyrum B. Johnson and Stan R. Szarek. 1972. Net CO fixation in crassulacean acid metabolism plants. Proceedings of Southern Section, American Society of Plant Physiologists/Cotton, Inc. :26-53. 16. PUBLICATIONS (Continued) Ting, I. P. , Hyrum Johnson and Stan R. Szarek. 1973. Gas exchange and productivity for Opuntia spp. Paper presented at International Biological Program Conference, Wales, April, 1973. (to be published in proceedings). Turner, J. C. 1972. Water, energy and electrolyte balance in desert bighorn sheep Ovis canadensis). Ph.D. Thesis, University of California, Riverside. 132 p. 17. FUTURE OBJECTIVES---FINANCIAL REQUIREMENTS Students of previous annual reports for the Philip L. Boyd Deep Canyon Desert Research Center will recall a number of recurring concerns expressed by the authors, who generally were identified as chairmen of the control committee within the department of biology. Appointment of Deep Canyon's first independent director (who reports to the vice chancellor directly) has not changed any of these concerns, although it permits perhaps a better articulation and expression of them. First, there remains the primary problem of land acquisition in order to protect the fragile environment, particularly pressing in 1973 due to increased private land speculation and/or development in the previously thought inaccessible Santa Rosa Mountains. The recommendation remains the same as in previous years--acquisition of inholding privately-owned land sections , particularly the three immediately south of the Deep Canyon station laboratory. A permanent endowment fund to support expanding research remains a major objective. Expanded budget funds to support both increased research and to provide additional support staff personnel and facilities needed to provide a base for such research. In that line, the needs include housing, improved domestic water retrieval and storage; additional jeep roads and trails, particularly upper elevation areas; a third laboratory and accompanying storage space; additional utilities, including electricity, telephone, natural gas or propane, sewerage and parking facilities. 18. To accomplish the 20-year study plan announced during the fiscal year, these things are mandatory, along with computer input, storage and retrieval capacity to serve researchers anywhere in the world who wish to use Deep Canyon's store of knowledge, either by computer or as preliminary informa- tion for their future research studies. A Preliminary and tentative budget expansion proposal is being prepared for submission in order that Deep Canyon's needs for future growth can be met. The budget request is being prepared with care so as not to handicap or inhibit any requests for on-campus research facilities at Riverside. The staff is continuing to explore ways and means of securing additional, supplemental funding from sources outside the university, to support current and contemplated future research discussed in the next section of this report. 19. PROPOSED AND/OR ANTICIPATED MAJOR PROGRAMS The director proposes a seminar-symposium series on an alternate-year basis to cover important and current aspects of desert biology. A proposal for the first is now being prepared. A joint Australian-U.S. comparative desert program is now in the proposal stage, both at UCR and at the Australian National University in Canberra. The physiology and biochemistry of desert succulents native to the American deserts and naturalized in much of Australia will be studied. A cooperative graduate-student program between Deep Canyon and the University of Coahuila, Mexico, has been proposed through the Dry-Lands Research Institute, UCR. It would emphasize greater use of cactus as animal fodder and human food in the southern republic. Also proposed is a computer storage-retrieval plan for phenological data in which seasonal changes in biomass, species, etc. , will be followed. The Deep Canyon "five-foot shelf" of books containing practical and useful information about Deep Canyon, and the Colorado Desert in general, is underway. Desert biology will be the primary emphasis of this series, which will continue the work of Mammals of Deep Canyon, by R. Mark Ryan (1969) , and Ants of Deep Canyon, by G. C. and Jeannette Wheeler (1973). These will be written in semi-popular style, in language suitable for use both by biologists and the lay public. Cooperative programs are being considered with Southern California land developers, designed to study the impact of development of desert land on ecosystems. A series of limited field courses for graduate students in desert 20. biology is contemplated to enhance existing programs and to provide greater use of Deep Canyon without disturbing its relatively pristine wilderness status. 21. VISITORS Use of the Deep Canyon center continued to increase during the fiscal year, although the present sign-in/sign-out registration procedure at the gate is admittedly an imperfect method of determining this activity, For example, sign-ins totaled 806 during the year, up from 616 in the 1971-1972 fiscal year, and only slightly below the all-time "record" of 813 logged in 1970-1971. Inasmuch as some visitors do not sign in and others are listed only as "and party" by the principal visitors the system is not accurate. Another example, more than 60 man-days were involved in relocation and remodeling of Palo Verde Cottage as the resident researcher's quarters. Some of the workers signed in daily; others did not. Some research projects involve visits to the upper elevations only and no registration is noted. Many short-term projects particularly are not logged at all. Nevertheless, for the benefit of those who measure success by numbers , here are two tables concerning visitation: TABLE 1--Total number of visitors by months July 14 August 27 September 39 October 29 November 71 December 73 January 75 February 113 March 135 April 123 May 59 June 40 22. TABLE 2 Origin of Visitors University of California--Riverside, Los Angeles, Berkeley, Santa Barbara, Davis, San Diego and Irvine. California State Universities--San Diego and Fullerton Other State Universities--Michigan, Utah State at Logan, Illinois, Nevada at Reno, Wyoming. Other U.S. Universities--Rutgers and Columbia. Pomona College. Foreign Universities--Paris, France; Moscow, USSR; Lund, Sweden; Oxford, England. Related Institutions--California Institute of Technology, Desert Research Institute at Reno, Los Angeles State-County Arboretum, Descanso Gardens, Living Desert Reserve. Conservation Groups--Nature Conservancy, Desert Protective Council. Federal Agencies--Bureau of Land Management, Forest Service, Weather Service, Geologic Survey, Fish and Wildlife Service. State Agencies--Department of Fish and Game, Department of Parks and Recreation, Division of Forestry. County Agencies--Parks Department, Sheriff's Department, Parks Advisory Commission, Coachella Valley County Water District. Other Agencies--Agua Caliente Indian Tribal Council. Museums--Malki of Morongo Indian Reservation, Desert Museum of Palm Springs. Distinguished University Guests--President Charles Hitch, Regent Edward Carter, Chancellor Ivan Hinderaker, Vice Chancellor James Sullivan, Dr. Mildred Matthias. Communications Media--U.S. Information Agency, National Broadcasting Co. , Los Angeles Times, Christian Science Monitor, Time-Life Books. Idyllwild Town Crier. 23. TABLE 2A Distinguished Visitors from the University of California President Charles Hitch Regent Edward Carter Chancellor Ivan Hinderaker Vice Chancellor James Sullivan Dr. Mildred Mathias, Los Angeles, Natural Land and Water Reserves System Dean W. M. Dugger Dr. E. Barnett, Regent's Lecturer Visiting Professors from foreign universities Otto Lange, West Germany Orlando Quieroz, Paris, France Ms. Gunnar Erlandson, Lund University, Sweden 24. STAFF PEMBERS Name Working Title Irwin P. Ting Director Bill Jennings Editor-Liaison Officer Jan Zabriskie Resident Biologist Karen Fowler Volunteer-rlammalogist Nancy Zabriskie Volunteer-Museum Scientist (# Mrs. Fowler is the fulltime director-administrator of Living Desert) The staff wishes to thank Mr. Philip L. Boyd, ex-Regent of the University of California for his unfailing interest and full support. the administrative staff of the Department of Biology, University of California, Riverside, also provides unflagging assistance and support for the center in innumerable ways, without which the small staff of the center would not be able to function. Particular research and academic support has been provided unselfishly by Saul Frommer, Oscar Clarke and Hyrum.Johnson. Philip L. Boyd Deep Canyon Desert Research Center f 1 � a. 17$ ^ 4 ONE M v� Q: Valley Studios,Hemet I This aerial photograph, from about 6,000 feet, was taken by Walter E. Frisbie, Hemet commercial photographer. It shows the station buildings at the 950-foot elevation near the L lower left corner. Deep Canyon Creek swings sharply north below the buildings, at the toe of Sheep Mountain. The canyon continues to the right (south) upstream into the lower gorge near the upper right corner of the picture. Jeep trails and the main road are barely discernible. FLORISTIC LIST FOR DEEP CANYON WATERSHED OCTOBER 1973 INTRODUCTION This is a current, partial floristic list for the Deep Canyon watershed, in two sections, compiled from previous lists and augmented by field observation and collection. It is nearly complete for the area from 400 feet to 3,600 feet, or from the mouth of the canyon to the merger zone of desert vegetation with the chaparral, evergreen trees and shrubs. The list includes all plant species known to occur in the Deep Canyon watershed. Those species not represented by Deep Canyon herbarium specimens are noted with an asterisk. The second section includes herbarium specimens taken from the Deep Canyon watershed above 3,600 feet. This section is less complete because of the minimal amount of collecting that has been done at higher elevations. In time, as herbarium facilities improve and field collecting expands, the list will be upgraded periodically. The goal is to present an accurate floristic list, on a continually growing basis. Family, genera and species are listed alphabetically. Nomenclature follows Munz and Keck's A California Flora, UC Press, 1959, and Munz's Supplement to a California Flora, UC Press, 1968. PHYSIOGRAPHY The Deep Canyon watershed drains a major area of the north and east slopes of the Santa Rosa Mountains. This peninsular subrange is _ Z .. of recent geologic origin, made up of highly metamorphosed sedimen- tary rock further deformed by igneous intrusion. The watershed comprises 40.70 square miles with a northerly elevation fall of 8,000 feet in 11.75 aerial miles from Toro Peak (8,716 feet) to i the alluvial plain near Palm Desert. Deep and Horsethief creeks begin as small. gullies on the steep upper slopes. At 4,000 feet these slopes level. abruptly to a low- relief plateau which gradually drops to about 2,500 feet. Each watercourse cuts through the plateau in arroyos that join at the 2,800-foot elevation. The descending plateau is broken by three promonotories, Sheep Mountain (5,141 feet) , Sugarloaf (4,776 feet) and Black Hill (3,689) . At their confluence the two ephemeral , intermittent streams enter a steep-walled gorge that bends 90 degrees northerly and drops precipitously through a chasm created by geologic faulting and deepened by subsequent erosion. Vertical walls in places are more than 1,400 feet high, effectively isolating the canyon floor from the plateau above. At approximately 1,300 feet elevation the gorge widens about the apex of a huge alluvial fan. The Deep Canyon fan and several others to the east and west blend into the alluvial plan. CLIMATE Climatic characteristics are high summer temperature, low and - i.i - erratic rainfall and strong vernal winds. Rainfall data from the Deep Canyon station (950 feet) show an 11-year annual average of 3.95 inches. Most rain occurs in winter storms that penetrate the rain shadow created by mountains to the west. Summer thunderstorms are localized heavy downpours of short duration, often causing flash flooding. Daily maximum temperatures for the month of July over a six- year period averaged 101 degrees. On the floor of the Coachella Valley, which varies from 475 feet at Palm Springs to -185 feet at Mecca, rainfall averages slightly less and the temperature range is much greater, with a record high at Indio (-22 feet) of 125 degrees and a low of 13 degrees there, 11 miles east of the center. At the canyon's higher elevations temperatures are lower and precipitation greater, frequently in the form of winter snow. The daytime temperature difference between the 950-foot level and the 2,750-foot level averages 9.8 degrees. The following weather records are from the Deep Canyon station 950 feet. AVERAGE DAILY MAXIMUM AND MINIMUM TEMPERATURES FOR EACH MONTH, 1968-1973 Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Yr. Av. 69 65 69 73 77 88 95 101 99 94 83 72 64 82 50 54 57 59 68 74 81 80 76 67 57 49 64 ABSOLUTE MAXIMUM/MINIMUM TEMPERATURES FOR EACH MONTH, 1968-1973 Jan. Feb. Mar. Apr. May . June July Aug. Sep. Oct. Nov. Dec. 85 84 93 94 105 116 116 112 108 98 89 80 29 41 39 44 50 54 68 62 60 48 42 32 AVERAGE PRECIPITATION (inches) FOR EACH MONTH (1963-1973) Ann. Jan. Feb. Mar. Apr. May. Jun. Jul. Aug. Sep. Oct. Nov. Dec. Avg. 0. 24 0.30 0.47 0.17 0.07 0.03 0.32 0.47 0.31 0. 23 0.75 0.59 3. 95 Driest year: 1971, 1.37 inches precipitation Wettest year: 1965, 8.05 inches precipitation ACKNOWLEDGEMENTS This list was compiled by and material for the explanatory text provided by Jan Zabriskie, resident researcher at Deep Canyon. Additional collection and identification were provided by Nancy Zabriskie, museum scientist for the center. Earlier plant collection and identification were by Oscar Clarke, Saul Frommer, Lloyd Tevis, John Olmsted, Dr. Boyd Strain and others. -iv - FLORISTIC LIST FOR DESERT SLOPES AND FLOODPLAIN OF DEEP CANYON WATERSHED OCTOBER 1973 CHAROPHYTA Chara sp. LEPIDOPHYTA SF.LAGINELLACEAE elagineUa eremophila Maxon. Little club-moss PTEROPHYTA Ferns PTERIDACEAE A_diantum capMus-veneris L. Common maidenhair Cheilanthes coviZZei Maxon. Lip fern C. parryi (D.C. Eat.) Domin. Cloak fern Pe Uaea mucronata D. C. Eat. Bird's foot fern CONIFEROPHYTA Cone-bearing plants CUPRESSACEAE Cypress family ,Iuniperu:, caZifornica Carr. Juniper EPHEDRACEAE Ephedra family Ephedra aspera Engelm. ex Wats. Mexican tea E. nevadensis [,rats. Ephedra sp. PINACEAE Pine family Pinus monophylla Torr. & Frem. Pinyon. ANTHOPHYTA Angiosperms DICOTYLEDONEAE Dicots ACANTHACEAE Acanthus family - 1 - BeZoperonc caZifoiiii.ca Benth. Chuparosa AMARANTHACEAF. Amaranth family Amaranthus fimbriatus (Torr.) Benth. Amaranth Tidestromia cbZongifoZia (Wats.) Small. Honey sweet ANACARDIACEAE Sumac family Rhus ovata Wats. Sugarbush R. triZobata Nutt. Cx T. & G. var. anisophylla (Greene) Jeps.Squaw bush ASCLEPIADACEAE Milkweed family AscZepias aZbicans Wats. White-stemmed milkweed MateZea parvifoZia (Torr.) Woodson. Talayote Sarcostemma cynanchoides Dene. ssp. Hartwegii (Vail) R. Holm. Climbing milkweed S. hirtellum (Gray) R. Holm. Rambling milkweed BETULACF.AE Birch family AZnus rhombifoZia Nutt. White alder BIGNONIACEAE Bignonia family ChiZopsis Zinearis (Car.) Sweet. Desert willow BORAGINACEAE Borage family Amsinckia tessellata Gray. Fiddleneck Cryptantha angustifoZia (Torr.) Greene. Forget-me-not C. barbigera (Gray) Greene. 0. decipiens (Jones) Heller. C. maritima (Greene) Greene. C. micrantha (Torr.) Jtn. C. nevadensis Nels. & Kenn. C. pterocarya (Torr.) Greene. C. racemosa (Wats.) Greene. - 2 - C. utahensis (Gray) Greene. Pectocarya Zinearis var. ferocula Jtn. *P. pZatycarpa (M. & J.) M. & J. P. recurvata Jtn. Comb bur PZagiobothrys jonesii Gray. Popcorn flower BUXACEAE Box family Simmondsia, chinensis (Link) C. K. Schneid. Coatnut CACTACEAE Cactus family Eehiroeaetus acanthodes Lem. Barrel cactus E,chinocereus engeZmannii (Parry) Ruempl. Hedgehog cactus Mammillaria dioica K. Bog. Fishook cactus M. tetrancistra Engelm. Opuntia aeanthoearpa Engelm. & Bigel. Buckhorn cactus 0. basilaris Engelm. & Bigel. Beavertail cactus 0. bigeZovii Engelm. Jumping cholla 0. ehlorotiea Engelm. & Bigel. Pancake cactus 0. eehinoearpa Engelm. & Bigel. Golden cholla 0. ramosissima Engelm. & Bigel. Pencil cactus CAMPANULACEAE Bellflower family NemacZadus gZanduliferus Jeps. Thread plant N. rubescens Greene var. tenuis McVaugh. CAPPARIDACEAE Caper family Isomeris arborea Nutt. Bladderpod CARYOPHYLLACEAE Pink family Achyronychi,a cooperi T. & G. Frost mat CHENOPODIACEAE Goosefoot family - 3 -- Atriplex canescens (Pursh) Nutt. ssp. Zinearis (Wats.) Hall & Clements. Wingscale A. poZyearpa (Torr.) Wats. Cattle spinach A. semibaccata R. Br. Australian saltbush Chenopodium fremontii Wats. Pigweed Salsola pestifera A. Nels. Russian thistle, Tumbleweed COMPOSITAE Sunflower family Acamptopappus sphaerocephalus (Hare. & Gray) Gray Goldenhead Ambrosia acanthicarpa Hook. Sandbur A. dumosa (Gray) Payne. Burrobush A. psilostachya D. C. Ragweed Anisocoma acaulis T. & G. Scale bud Artemisia Zudovieiana Nutt. ssp. albula ([loot.) Keck. Wormwood Baccharis brachyphylla Gray. B. glutinosa Pers. Seep-willow B. sergiloides Gray. Sauaw waterweed B. viminea DC. Mule fat Bebbia juncea (Benth.) Greene. Sweetbush Brickellia arguta Rob. Brickellbush L'. californica (T.& G.) Gray. B. desertorum Cov. Chaenactis carphoclinia Gray. Pincushion C. fremontii Gray. C. xantiana Gray. Chrysothamnus teretifoZius (Dur. & Hilg.) Hall. Cirsium sp. Thistle Conyza canadensis (L.) Cronq. Horseweed - 4 - Dieoria canescens T. & G. Bugseed Dyssodia porophylloides Gray. Fncelia farinosa Gray. Incienso E. virginensis A. Nels. ssp. actoni (Elmer) Keck. Eriophyllum ambiguum (Gray.) Gray. Yellowfrocks E. confertifZorum (DC.) Gray. Long-stemmed eriophyllum E. wallacei (Gray) Gray. Filago arizonica Gray. F. caZifornica Nutt. Geraea canescens T.& G. Desert sunflower Gutierrezia sarothrae (Pursh) Britt. & Rusby. HapZopappus cuneatus Gray. Goldenbush H. ZinearifoZius DC. Goldenbush Hofineisteria pZuriseta Gray. Arrowleaf HymenocZea salsola T.& G. Cheesebush Laetuea serriola L. Prickly lettuce MaZacothrix gZabrata Gray. Desert dandelion M. stebbinsii Daris & Raren. Microseris ZinearifoZia (Nutt) Sch-Bip. Silver puffs MonoptiZon bellioides (Gray) Hall. Desert star PaZafoxia Zinearis (Car.) Lag. Spanish needle Peetis papposa Harv. & Gray ex Gray. Cinch weed PerityZe emoryi Torr. in Emory. Rock daisy l'eucephyllum schottii (Gray) Cray. I)esert fir Pluchea sericea (Nutt.) Cov. Arrow weed Porophyllum graciZe Benth. Poreleaf Psathyrotes ramosissima (Torr.) Gray. Desert velvet - 5 - Rafinesquia californiea Nutt. Chicory N. neomexicana Gray. Senecio douglasii DC. Groundsel Sonchus oleraceus L. Sow-thistle Stephanomeria exigua Nutt. Annual mitra S. paucifZora (Torr.) Nutt. Desert-straw *StyZocZine gnaphaZoides Nutt. Trichoptilium incisum (Gray) Gray. Yellowhead Trixis caZiforniea Kell. Viguiera deltoidea Gray. var. parishii (Greene) Vasey & Rose Golden eye CRASSULACEAE Stonecrop family DudZeya arizonica Rose. Broad-leaved live-forever DudZeya saxosa (Jones) Britt. & Rose ssp. aloides (Rose) Moran Narrow-leaved live-forever Ti Naea erecta H. & A. Pigmy weed CROSSOSOMATACEAF Crossosoma family Crossosoma bigeZovii Wats. Rockflower CRUCIFERAE Mustard family Arabic perennans Wats. Rock cress Brassica tournefortii Govan. Caulanthus cooperi (Wats.) Pays. C. hallii Pays. Descurainia pinnata (Walt.) Britton ssp. glabra (Woot. & Standl.) Detl. Tansy mustard Dithyrea caZifornica Harr. Spectable pod Draba cuneifoZia Nutt. ex T.& G. var. integrifolia [eats. - 6 - Lepidium Zasiocarpum Futt. Peppergrass Sisymbrium irio L. London rocket Streptanthe Ua Zongirostris (Wats.) Rydb. Twist flower TheZypodium Zasiophy Uum (II.& A.) Greene. var. utahensis (Pydb.) Jeps. Thysanocarpus curvipes Hook. var. eradiatus Jeps. CUCURBITACEAE Gourd family Brandegea bigeZovii (Wats.) Cogn. Cucurbita paZmata Wats. Wild gourd CUSCUTACEAE Cuscuta denticulata Engelm. Dodder ERICACEAE Heath family ArctostaphyZos gZauca Lindl. Manzanita EUPHORBIACEAE Spurge family Bernardia incana Mort. Mouse eye Ditaxis Zaneeolata (Benth.) Pax & K. Hoffm. Silver bush D. neomexicana (Muell.-Arg.) Heller. Euphorbia aZbomarginata T.& G. Rattlesnake weed E. eriantha Benth. Desert poinsettia E. micromera Boiss. E. poZycarpa Benth. Sand mat F. revoluta Engelm. E. .:,etiZoba Engelm. E. supina Raf. Stillingia ZinearifoZia Wats. FAGACEAE Beech family Quercus dumosa Nutt. Scrub oak - 7 - FOUQUIERIACEAE Ocotillo family Fouquieria splendens Engelm. Ocotillo GENTIANACEAE Gentian family Centaurium venustum (Gray) Rob. GERANIACEAE Geranium family Erodium cicutarium (L.) L'Her. Filaree E. texanum Gray. HYDROPHYLLACEAE Waterleaf family Emmenanthe penduZifZora Benth. Whispering bells Eriodictyon trichocaZyx Heller. Yerba santa Eucrypta chrysanthemifolia (Benth.) Greene. var. bipi.nnatifida (Tory.) Const. E. micrantha (Torr.) Heller. Nama demissum Gray. Purple mat Phacelia affinis Gray. P. campanularia Gray. P. crenulata Torr. P. cryptantha Greene. P. distans Benth. P. fremontii Torr. P. Zemmonii Gray. P. pedicellata Gray. PhoZistoma membranaceum (Benth.) Const. KRAMERIACEAE Krameria family Krameria grayi Rose & Painter. K. parvifoZia Benth. var. imparata Macbr. - 8 - LABITAE Mint family Hyptis emoryi Torr. Desert lavendar Monardella Zinoides Gray. Narrow-leaved monardella SaZazaria mexicana Torr. Bladder sage SaZvia apiana Jeps. var. compacta Munz. White sage S. columbariae Benth. Chia S. eremostachya Jeps. Sand sage S. vaseyi (Porter) Parish. Bristle sage Stachys aZbens Gray. LEGUMINOSAE Pea family Acacia greggii Gray. Catclaw Amorpha fruticosa L. var. occidenta"l.is (Abrams) Kearn. & Peeb. AstragaZus aridus Gray. Locoweed A. coccineus Bdg. Scarlet locoweed Cassia covesii Gray. Senna Cercidium fZoridum Benth. Palo verde DaZea emoryi Gray. Dyeweed D. mollis Benth. Silk dalea D. mollissima (Rydb.) Munz. D. parryi T.& G. D. schottii Torr. Indigo bush 0. spinosa Gray. Smoke tree Hoffmannseggia mierophylla Torr. Rush pea Lotus heermannii (Dur. & Hilg.) Greene. *L. humistratus Greene. L. nevadensis Greene. L. rigidus (Benth.) Greene. Rock pea - 9 - L. salsuginosus Greene. var. brevivexillus Ottley. L. scoparius (Nutt. in T.& G.) Ottley var. breviaZatus Ottley. Deer weed L, tom..te Nus Greene. Lupinus arizonieus (Wats.) Wats. Lupine L. concinnus J.G. Agardh. var. orcuttii (Wats.) C.P. Sm. L. shockleyi Wats. McZiZotus indieus (L.) All. Sweet clover Prosopis gZanduZosa Torr. var. torreyana (L. Benson) M.C. Jtn. Mesquite LOASACEAE Loasa family M�,`tzelia aZbicaulis Dougl. ex Hook. Blazing star M. involucrata Wats. Petalonyx thurberi Gray. Sandpaper plant LORANTHACEAE Mistletoe family Phoradendron boZZeanum (Seem.) Eichler ssp. densum (Torn.) Wiens. Juniper mistletoe P. caZifornicum Nutt. Desert mistletoe LYTHRACEAE Lythrum caZifornicum T.& G. MALVACEAE Mallow family L'remalche rotundifoZia (Gray) Greene. Desert five-spat Hibiscus denadatus Benth. Desert hibiscus SphaeraZcea ambigua Gray. Desert mallow S. ambigua Gray. ssp. rosaeea (M.& J.) Kearn. - 10 - NYCTAGINACEAE Four o'clock family Abronia viZZosa Wats. Sand verbena Allionia incarnata L. Windmills Boerhaavia erecta L. var. intermedia (Jones) Kearn. & Peeb. Ring stem B. coccinea Mill. Mirabilis bigeZovii Gray. Wishbone bush M. bigeZovii Gray var. retrorsa (Heller) Munz. M. froebelii (Behr) Greene var. gZabrata (Standl.) Jeps. Giant four o'clock M. tenuiZoba Wats. White four o'clock OLEACEAE Olive family Praxinum veZutina Torr. var. coriacea (Wats.) Rehd. Ash ONAGRACEAE Evening primrose Oenothera abramsii Macbr. 0. avita W. Klein. 0. cardiophy Ua Torr. 0. chamaenerioides Gray. 0. cZaviformis Torr & Frem. Brown-eyed primrose 0. decorticans (H.& A.) Munz. ssp. condensata (Munz) Munz. Bottle-cleaner 0. Zeptocarpa Greene. 0. micrantha Hornem. Zauschneria caZifornica Presl. ssp. mexicana (Presl.) Raven. California fuchsia X. cali.fornica Presl. ssp. lafij'olla (Hook.) Keck. - 11 - OROBANCHACEAE Broom-rape family Orobanche fasciculata Nutt. var. Zutea (Parry) Achey. Broom-rape 0. Zudoviciana Nutt. var. ZatiZoba Munz. PAPAVERACEAE Poppy family Argemone munita Dur. & Hilg. ssp. argentea G. Ownbey. Prickly poppy EschschoZzia minutifZora Wats. Little golden-poppy E. parishii Greene. Large golden poppy PLANTAGINACEAE Plantain family PZantago insularis Eastw. var. fastigiata (Morris) Jeps. Plantain POLEMONIACEAE Phlox family Kria: trum eremicum (Jeps.) Mason. 1". pluri.florum (Heller) Mason. Gilia austraZis (Mason & A. Grant) V. Grant G. ZatifoZia Wats. LangZoisia schottii (Torr.) Greene. L. setosissima (T.& G.) Greene. LeptodactyZon pungens (Torr.) Rydb. ssp. Hallii (Parish) Mason. Linanthus nuttallii (Gray) Greene ex Mlkn. ssp. f7oribundus (Gray) Munz. I;. dichotomus Benth. Evening snow *Z;. ,jonesi i. (Gray) Greene. POLYGONACEAE Buckwheat family Chori:zanthe brevieornu Torr. C. rigida (Tory.) T.& G. spiny herb Eriogonum apieulatum Wats. Buckwheat E. davidsonii Greene. E. fasciculatum Benth. var. po UfOZi-um (Benth.) T.& G. - 12 - F. infZatum Torr. & Frem. Desert trumpet E. pusillum T.& G. E. thomasii Torr. *E. trichopes Torr. E. wrightii Torr. ex Benth. var. membranaceum S. Stokes ex Jeps. Oxytheca emarginata Hall. Pterostegia drymarioides F.& M. PORTULACACEAE Purslane family CaZyptridium monandrum Nutt. in T.& G. Sand cress Montia perfoZiata (Donn.) Howell. var. parvifZora (Dougl.) J. T. Howell. Miner's lettuce M. spathulata (Dougl.) Howell. RANUNCULACEAE Crowfoot family Delphinium parishii Gray. Larkspur RESEDACEAE Mignonette family *OZigomeris ZinifoZia (Vahl) Macbr. Cambess RHAM_NACEAE Buckthorn family CondaZia parryi (Torr.) Weberb. Desert jujube Rhamnus crocea Nutt. in T.& G. ssp. ilieifoZia (Kell.) C. B. Wolf. Buckthorn ROSACEAE Rose family Prunu:; frcr oal,ii. Wats. Desert apricot RUBI:ACEAE Madder family GaZium aparine L. Bedstraw G. stellatum Kell. ssp. eremicum (Hilend & Howell) Ehrend. SALICACEAE Willow family PopuZus fremontii Wats. Cottonwood - 13 - Sa'Zix gooddingii willow A Zasio kpis Benth. SCROPHULARIACEAE Figwort family Antirrhinum cyathiferum Benth. Snapdragon A. §Zipes Gray. Twining snapdragon rastiZZeja foUoZo,sa HA A. Indian paintbrush Q stenantha Gray. Y_eckiella. antirrhinoidow (Benth.) Straw, ssp, microphplO, (Gray) Straw. Beard tongue MimuZus bigeZovii (Gray.) Cray. Monkey flower M, cardinaZis Dougl, ex Benth. M, f0ribundus Dougl. ex Lindl. A guttatus Fisch, ex DC, A nasutus Greene. A parishii Greene. A piZosus (Benth.) Wats. ,Vohavea confertifZora (Benth. in DC.) Heller. Ghost flower Penstemon Wevekndii Gray. P. spectabilis Thurb. ex Gray. SOLANACEAE Nightshade family Datura meteZoides A. DC. Jimson weed Lycium andersonii Gray. Desert thorn Nieotiana trigonophylla Dunal in A. DC. Desert tobacco PhysaZis crassif&ia Benth. Ground cherry 5olanum nodifZorum Jacq. Nightshade - 14 - STERCULIACEAE Cacao family Ayenia, compacta Rose TAMARTCACEAE Tamarisk family Tamarix pentandra Pall. Tamarisk T. aphylla (L.) Karst. Athel tamarisk URTICACEAE Nettle family Parietaria fZoridana Nutt. Pellitory VERBENACEAE Verbena family Verbena Zosiostachys Link. Vervain VITACEAE Grape family Vitis girdiana Munson. Grape ZYGOPHYLLACEAE Calptrop family Fagonia Zaevis Standl. Larrea tridentata Sesse & Mocino. Creosote bush TribuZus terrestris L. Puncture vine MONOCOTYLEDONEAE AGAVACEAE Agave family Agave deserti Engelm. Desert agave NoZina parryi Nolina Yucca shidigera ex. Ortigies. Mohave yucca Y. whippZoi Torr. Our Lord's candle AMARYLLIDACEAE Amaryllis family Muilla coronata Greene. CYPERACEAE Sedge family HeZeocharis montevidensis Kunth. Spike rush - 15 - GRAMINEAE Grass family Agrostis semiverticillata (Forsk.) C. Chr. Bent grass Ar/-s( ido adscensionic L. Triple-awned grass A. parishii Hitchc. BouteZoua aristidoides (HBk.) Griseb. Grama grass B. barbata Lag. Bromus rubens L. Foxtail Cynodon dactyZon (L.) Pers. Bermuda grass Festuea megaZura Nutt. Fescue F. octofZora Walt. Hilaria rigida (Thurb.) Benth. ex Scribn. Galleta 11ordeum stebbinsii Covas. Barley LeptoehZoa uninervia (Presl.) Hitchc. & Chase. Sprangletop McZica frutescens Scribn. MuhZenbergia asperifoZia (Nees. & Mey.) Parodi. Scratch grass M. microsperma (DC.) Kunth. M. rigens (Benth.) Hitchc. Pennisetum setaceum (Forsk.) Chiov. Poa bigeZovii vasey & Scribn. PoZypogon monspeliensis (L.) Desf. Beard grass 'ohi.-mu:. barbatus (L.) Thell . ��poroho l w, ai.roide:: (Tore.) Torr.. Dropseed „tipa, "peoiooa Trin. & Rupt. Spear grass Tridens puZehellus (HBR.) Hitchc. Fluff grass IRIDACEAE Iris family *Sisyrinchium bellum Wats. Blue-eyed grass - 16 - JUNCACEAE Rush family .Iuncus baZticus Willd . Rush .!. bufoni: L. Toad Rush J. xiphioides E. Mey. PALMAE Palm family Washingtonia ,filifera (Lindl.) Wendl. Fan palm LILIACEAE Lily family *CaZochortus eoncoZor (Baker) Purdy. Goldenbowl mariposa TYPHACEAE Cat-tail family Typha domingensis Pers. Cat-tail - 17 - PARTIAL FLORISTIC LIST FOR THE CHAPARRAL, WOODLAND, AND YELLOW*PINE FOREST OF THE DEEP CANYON WATERSHED OCTOBER 1973 PTEROPHYTA Ferns Pteridaceae Cheilanthes covi Nei Maxon. Lip fern Pellaea mucronata D.C. Eat. Bird's foot fern Pityrogramma triangularis (Kaulf.) Maxon. Goldenback fern CONIFEROPHYTA Cone-bearing plants CUPRESSACEAE Cypress family *CaZoeedrus deeurrens (Torr.) Florin. Incense cedar Juniperus caZi-fornica Carr. .Juniper PINACEAE Pine family *Abies eoncoZor (cord. & Glend.) Lindl. White fir *Pines jeffreyi Grev. & Balf. in A. Murr. Jeffrey pine Pinus monophylla Torr. & Frem. Pinyon pine *P. ponderosa Dougl. ex P.C. Lawson. Ponderosa pine P. quadrifoZia Parl. ex Sudw. ANTHOPHvTA Angiosperms DICOTYLEDONEAE Dicots AMAItANTHACEAE Amaranth family /lmaranthur, albus L. Tumbleweed ANACAR.DIACEAE Sumac family Rhus ovata Wats. Sugarbush - 18 - BERBERIDACEAE Barberry family Berberis dictyota Jeps. Barberry BETULACEAE Birch family Alnus rhombifoZia Nutt. White alder CACTACEAE Cactus family Opuntia erinacea Engelm. & Bigel. var. ursina (A. Weber_) Parish. Grizzly Bear cactus 0. erinacea Engelm. & Bigel. var. xanthostemma (K. Schum.) L. Benson. Old man cactus 0. ZittoraZis (Engelm.) Ckll. Prickly-pear CAPRIFOLIACEAE Honeysuckle family Symphoricarpos parishii Rydb. Snowberry CARYOPHYLLACEAE Pink family Silene verecunda Wats. ssp, platyota (Wats.) Hitchc. & Maguire. COMPOSITAE Sunflower family Artemisia dracunculus L. Wormwood A. Zudoviciana Nutt. ssp, albula (Woot.) Keck. Bahia dissecta (Grav) Britton. Chrysothamnus nauseosus (Pall.) Britton. ssp. bernardinus (Hall) Hall & Clem. Rabbitbrush Corethrogyne filaginifoZia (H.& A.) Nutt. var. brevicula (Greene) Canby. Dyssodia porophylloides Gray. F,riophyllum confertiflorum (DC.) Gray. <Inaphalium palustre Nutt. Cudweed 6'utierrezia :,arothrac, (Pursh) Britt . & Rushy. Matchweed Haplopappus cuneatus Gray. Goldenbush - 19 - H. ZinearifoZius DC. Hymenopappus filifoZius Hook. var. Zugens (Greene) Jeps. Lessingia germanorum Cham. var, gZanduZifera (Gray) J. T. Howell. Machaeranthera canescens (Pursh) Gray. Senecio dougZasii DC. Groundsel SoZidago caZifornica Nutt. Goldenrod EUPHORBIACEAE Spurge family bernardia incana Mort. Mouse-eye FAGACEAE Oak family *Quercus agrifoZia Nee. *Q. chrysolepis Liebm. *Q. turbinella Greene. GARRYACEAE Silk-tassel family Garrya fZavescens Wats. var. pallida (Eastw.) Bacig. ex Ewan. Silk-tassel bush HYDROPHYLLACEAE Waterleaf family Friodietyon crassifoZiurn Benth. Yerba Santa LABIATAE Mint family Monardella Zinoides Gray. M. nana Gray. ssp. arida (Hall) Abrams. M. nana ssp. tenuifZora (Wats.) Abrams. SaZvia apiana Heps. var. compacta White sage S. pachyphylla Epl. ex Munz. Stachys rigida Nutt. ex Benth. Hedge nettle 20 - LEGUMINOSAE Pea family AstragaZus coccineus Bdg. Scarlet locoweed A. paZmeri Gray. Amorpha fruticosa L. var. occidentaZis (Abrams) Kearn. & Peeb. Lotus davidsonii Greene. L. nevadensis Greene. L. rigidus (Benth.) Greene Lupinus concinnus J.G. Agardh var. orcuttii (Wats.) C. P. Sm. Lupine L. formosus Greene var. hyacinthinus (Greene) C. P. Sm. LINACEAE Flax family Linum perenne L. ssp. Zewisii (Pursh.) Hult. Flax LORANTHACEAE Mistletoe Phoradendron boZZeanum (Seem.) Eichler ssp. densum (Torr.) Fosb. Juniper mistletoe MALVACEAE Mallow family MaZacothamnus fasciculatus (Nutt.) Greene SphaeraZcea ambigua Gray. OLEACEAE Olive family Foresteria neo-mexicana Gray. Desert olive Fraxinus veZutina Torr. var. coriacea (Wats.) Rehd. Ash ONAGRACEAE Evening-primrose family Zauschneria caZifornica Presl. ssp. ZatifoZia (Hook.) Keck. California fuchsia PAPAVERACEAE Poppy fam:i.ly Argemone muni to Dur. & 11i1g. 1'rick.1-y poppy - 21 - POLEMONIACEAE Phlox family F,riastrum sapphirinwn ssp. gynmocephalwn Li.nanthus nuttallii (Gray) Greene ex Mlkn. L. nuttallii (Gray) Greene ex Mlkn. ssp. floribundus (Gray) Munz. PhZox austromontana Cov. POLYGONACEAE Buckwheat family Eriogonum apieulatum Guts. Buckwheat E. davidsonii Greene. Z'. maculatum Heller. E. saxatiZe Wats. E. wrightii Torr. ex Benth. var. subscaposum Wats. E. wnbellatum Torr. var. stellatum (Benth.) Jones. Oxytheca emarginata Nall. PORTULACACEAE Purslane family Montia perfoliata (Donn) Howell. var. parvifZora (Dougl.) J. T. Howell. Miner's lettuce RANUNCULACEAE Crowfeet family /Iquilegia formosa Fisch. in. DC. var. trurzeata (F.&M.) Baker. Columbine Clematis paucif'Zora Nutt. in T.& G. Clemantis RHAMNACEAE Buckthorn family Ceanothus greggii Gray. var. perplexans (Trel.)Jeps. California lilac Rh=nus crocea Nutt. in T.& G. ssp. ilicifoZia (Kell.) C. B. Wolf. Buckthorn ROSACEAE Rose family ,1denosLoma sparsifnZi7.pp Torr. Ribbonwood Amelanchier palZida Greene. Service-berry - 22 - Cercocarpus betuZoides Nutt. ex T.& G. Mountain mohagany Prunus fasciculata (Torr.) Gray. Desert almond P. ilieifoZia (Nutt.) Walp. Holly-leaved cherry Purshia glandulosa Curran. Antelope bush RUBICEAE Madder family GaZium andrewsii Gray. G. angustifoZium Nutt. in T.& G. var. bo rnardi.num Hi.lend & Howell. G. parishii Hilend & Howell. RUTACEAE Rue family Thamnosma montana Torr. & Frem. Turpentine broom SALICACEAE Willow family SaZix Zaevigata Bebb. Willow SAXIFRAGACEAE Saxifrage family PhiladeZphus microphyllus Gray. ssp. stramineus (Rydb.) C. L. Hitchc. Mock orange P,ibes eereum Dougl. Squaw current SCROPHULARIACEAE Figwort family Casti U eja foZioZosa H.& A. Indian paintbrush C. martinii Abrams. Cordylanthus filifoZius Nutt. ex Benth. in DC. Bird's-beak C. nevinii Gray. Keckie Na antirrhinoides (Benth.) Straw. ssp. microphylla (Gray) Straw. Beard tongue MimuZus cardinaZis Dougl.. ex Benth. Monkey flower M. f Zoribundu.^ Dougl. ex I,indl. M. pilosus (Benth.) Wats. Penstemon spectabilis Thurb. ex Gray. - 23 - P. Zabrosus (Gray) Hook. SOLANACEAE Nightshade family Solanum zantii Gray. var. montanum Munz. Nightshade TAMARICACEAE Tamarisk family Tamarix petandra Pall. Tamarisk UMBELLIFEREAE Carrot family Lomatium mohavense (Coult. & Rose) Coult. & Rose. MONOCOTYLEDONAE AGAVACEAE Agave family NoZina parryi Wats. AMARYLLIDACEAE Amaryllis family Allium fimbriatum Wats. wild onion GRAMINEAE Grass family Stipa coronata Thurb. in Wats. var. depauperata (Jones) Hitchc. - 24 - Philip L. Boyd Deep Canyon Desert Research Center limn b • 4 Ij VA i 6 ' 4k Y Valley Studios,Hemet I r This aerial photograph, from about 6,000 feet, was taken by Walter E. Frisbie, Hemet commercial photographer. It shows the station buildings at the 950-foot elevation near the lower left corner. Deep Canyon Creek swings sharply north below the buildings, at the toe of Sheep Mountain. The canyon continues to the right (south) upstream into the lower gorge near the upper right corner of the picture. Jeep trails and the main road are barely r discernible. W ANNUAL REPORT 1973 - 1974 INTRODUCTION The fiscal year 1973-1974 was one of the busiest, most fruitful and challenging in the history of the Philip L. Boyd Deep Canyon Desert Research Center, established in 1959. More visitors were recorded than in any previous year. (Table 1) Deep Canyon produced its first university-published book, Ants of Deep Canyon. (Publications Section) . Mammals of Deep Canyon (1968) V was published by Desert Museum. A greater number of short and longrange research projects were reported. (Table 3) Perhaps the most important research news, however, was assurance that the.National Science Foundation would fund the Deep Canyon-Australian National University study "Environmental Control of Photosynthesis and Growth of Cactus Species (Opuntia) in Native and Introduced Habitats." A $23,251 grant was announced in September, 1974. Work in both countries will begin Jan. 1, 1975, for a two-year period. The study is the first direct Deep Canyon NSF project in a decade, although the center has been used for cactus , nematode and small mammal studies by the Desert Biome program. Dr. Irwin P. Ting, UCR professor of plant physiology and Deep Canyon director, and Dr. C. B. Osmond of ANU are principal investigators for the new study. ' Landline telephone service was completed, ending a long agreement for radio-telephone equipment. Class and special-group use of the center's facilities increased. (Table 2A) The continuing arthropod survey undertaken in 1963 progressed under direction of Saul Frommer, UCR museum scientist. A cooperative study program with the .center's new neighbor, Ironwood Country Club began, partially financed by the land development firm. (Summary reports are included) Thanks to the California personalized motor vehicle license program, an important habitat site was purchased by the State Department of Fish and Game to protect the only known range of the Desert Slender Salamander, near Deep Canyon. Additional trailer housing facilities at the station and at 2,750- feet were improved with air-conditioning and sanitation for the lower area ar and electricity for the upper trailer, an overnight-use shelter. The little trailer's circuits and air-conditioner were linked to the electric line from the Anza Electric Cooperative's Pinyon Flats-Royal Carrizo service area. Additional laboratory equipment was installed, including a water deion- izer, ice maker and ice crusher, all primarily for plant studies. Three species lists--plants , arthropods and birds--were produced and are available on request. No staff changes were made during the year. Jan Zabriskie remained the resident researcher, assisting long and shortterm researchers and expanding the center's plant collection, with one additional herbarium cabinet. Bill Jennings, the center's editor, conducted promotion and sales programs for Ants of Deep Canyon and began writing a second Deep Canyon book, �r — Deep Canyon, A Desert Wilderness for Science. This general-interest type book will be published this fiscal year. Staff volunteers Nancy Zabriskie and Karen Fowler were joined by Margaret (Peggy) Merritt, who assisted Dr. Jack C. Turner with his continuing bighorn sheep studies. The three women are the only accredited volunteers 2 on the Deep Canyon staff. .. An October meeting for the UC Natural Land and Water Reserves fund- raising group included a visit to the center. Liaison between the center and the Australian National University was increased with the arrival of Dr. Bruce Sutton from Canberra as a post-doctoral fellow working on Opuntia with Drs. Ting and Osmond. The challenges of inflation and the continuing energy crisis did not affect either the quality or quantity of research at Deep Canyon and requests for center use in 1974-1975 are running as high as last year. Rainfall and average maximum/minimum temperatures for the immediate area during the year were not substantially different from the long-range record. A total of 3.63 inches of rainfall was recorded, as compared with 5.02 inches the previous fiscal year. The heaviest one-month rainfall total in recent years was reported in January, 1974, when gauges measured 2.46 inches. R.ainfall summaries from 1963 are available on request , along with temperature records. WEATHER TABLE Average max/min temperatures and rainfall (in degrees F and inches) July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June 104 101 97 88 72 60 62 70 74 82 90 105 78 78 73 69 54 53 47 53 54 60 64 78 73 0 0 0 .09 0 2.46 0 .35 0 0 0 Mr. Zabriskie expanded long-range plant studies with the addition of a permanent plot in a desert pavement habitat, on the Pipestrelle Canyon alluvial fan. It supplements three previously established in the study of seasonal and yearly changes of annual plants, The first three line transects of several contemplated have been established for recording perennial plant phenology along an altitudinal 3 ,y gradient on the canyon transect. Plant collecting in the chaparral, pinyon woodland and pine forest communities continued through the spring. Specimens collected the previous spring have been incorporated in the herbarium. These bring to 834 the number of specimens and the species count to 429, not limited to the Deep Canyon transect but also including adjoining areas of the Santa Rosa Mountains. Seeds collected last summer and fall also are being added to the collection. Mrs. Nancy Zabriskie, museum scientist for the center, has completed the plant cataloging system and is continuing to prepare herbarium specimens and collect in the field, assisted by her husband, Walter, who has retired as an administrator in the Los Angeles Schools. The center's other volunteers , Ms. Karen Fowler, director-naturalist at nearby Living Desert Reserve, and Ms. Margaret Merritt, both worked with Dr. Turner on the bighorn sheep physiological and behaviorial study. SALAMANDER RESERVE The California Wildlife Conservation Board announced in January, 1974, that an ecological reserve of about 140 acres had been established near Deep Canyon to protect the Desert Slender Salamander (Batrachoseps aridus) , which is not known to inhabit any other area. This rare and endangered species is a relict and little research has been accomplished to date other than by Dr. Arden Brame of the Eaton Canyon Nature Center, Pasadena. Deep Canyon personnal helped to establish a plan for the new reserve, including restrictions on research there. 4 INTER-AGENCY COOPERATION Deep Canyon personnel are cooperating with three state agencies on varied programs of importance to present and future research in the Santa Rosa Mountains. One, mentioned previously, involves a management plan for the new desert slender salamander ecological reserve. A second, more informal agreement concerns weather recording equip- ment and data at the newly-completed Pinyon Crest Fire Station of the California Division of Forestry and the Riverside County Fire Department. Deep Canyon will install seven-day recording weather instruments there for joint use of the two fire agencies and the university. Also continuing is an informal working arrangement with Anza-Borrego Desert State Park archaeological and park naturalist personnel. Currently park specialists are studying skulls and other remains of desert bighorn sheep to measure the differences between the Santa Rosa herds and sheep found further south, hopefully to determine the subspecies question that is still debated among zoologists. Deep Canyon personnel work closely with Living Desert Reserve officials, particularly in the area of plant studies and the behaviorial and physio- logical study of desert bighorns begun three years ago by Dr. Jack C. Turner, now of the University of Wyoming. Insect light trapping is being coordinated with the Coachella Valley Mosquito Abatement District at three sites. �r PUBLICATIONS During the year the Boyd Center's publications program expanded. Three species lists--for plants, birds and arthropods--were released for general distribution. A fourth, combining mammals , reptiles and amphibians , 5 -10 is now in a preliminary form. R. Mark Ryan's Mammals of Deep Canyon, published by the Palm Springs Desert Museum was the first book wholly devoted to Deep Canyon research when it appeared in 1968. It is still in print and is a valuable reference work on many desert biologists ' bookshelves. During December, 1973, the center's own initial book-length publica- tion appeared. Ants of Deep Canyon, by G.C. and Jeanette Wheeler of the University of Nevada Desert Research Institute, has had good critical notices and slow but steady sales. It is the first in an annual series of Deep Canyon-sponsored publications. The second, Deep Canyon, A Desert Wilderness for Science, by the center's editor, is now at the manuscript stage and should be published during this fiscal year. Subsequent themes may include amphibians, succulent plants, bighorn sheep, archaeology and other plant and animal forms. There continues to be public interest in Deep Canyon studies, mani- fested by newspaper inquiries. Much of this vicarious attention has been devoted to the desert bighorns in the past but increasing concern is being expressed in more general ecological and environmental studies. FACILITIES IMPROVED Under this heading the center has limited activity to report for the year. The major item was completion of the landline telephone by General Electronics and Telephone from its Pinyon Crest exchange. It was started in the previous fiscal year but terrain difficulties delayed construction and inhibited good service at first. The line utilizes the Anza Electric Cooperative power poles installed several years ago, thus reducing the visual annoyances of another line in such a scenic area. 6 The telephone which entered service in February replaced the cumber- some but vital radio-telephone link installed in 1962 by Chalfont Com- munications. The Deep Canyon staff expresses its thanks to Chalfont for service far beyond the limits of a contract. Emergency repairs and message-taking were always cheerfully handled. For the benefit of Deep Canyon users our new telephone number is (714) 349-3655, in the Pinyon exchange. We cannot extend UC tie-line service or connect the line to the UCR campus computer as yet. Travel trailers added last year were made more liveable with install- ation of air-conditioning and a septic system. The old (1956) "Went Trailer" as the first Deep Canyon unit is still called in honor of Dr. Frits Went, also received air-conditioning. Electricity was extended also to a small overnight trailer at the 2,750-foot elevation near Boyd's Point. Users must still provide water and LPG for cooking purposes and the trailer has no direct septic system. The center requested approximately $6,500 in minor capital improvements during the 1975-1976 fiscal year as part of the annual campus program. Included are a shade (energy-saving and esthetic) ramada over the three trailers at the 950-foot elevation main station, also an asphalt (safety and esthetic) apron under them, conversion of the original generator shed into a more usable storage area by removal of the surplus generators and raising of the slanting shed roof to conform with the adjoining storage and water cistern building. Incidental roof repair and painting also were requested. Continuing electrical and water system improvements have been made as center budgets permitted, along with donations from longtime Deep Canyon supporters. Following are special sections and tables accompanying the narrative 7 �r portion of this annual report. Copies of appendices and other special reports are available on request from: The Deep Canyon Office c/o Department of Biology University of California Riverside, CA 92502 �r V 8 RESEARCH ACCOMPLISHED Research conducted at the Philip L. Boyd Deep Canyon Desert Research Center during the fiscal year 1973-1974 remained as diversified as in earlier years , with the major interest in mammal ecology and physiology, also plant physiology. Two graduate students completed field requirements for doctoral degrees and another completed work for a master's degree, in addition to ongoing research projects of other graduate students, post- doctoral fellows and faculty research personnel from the University of California system and other institutions. As reported to the Natural Land and Water Reserves System office in Berkeley, station usage was as follows : All UC branches: Teaching - Research man-hours - 3,973 Other institutions : Teaching - Research man-hours - 1,119 Total number of UC users was 414; others , 210. The combined total, 624, compared with a total sign-in of 855. These data compare favorably with previous years,. reflecting an approximate 10 per cent annual gain in most areas. The total number of users in 1973-1974 was approximately half that in 1972-1973 but this apparent decline is due to a change in registration procedures. Highlights of the major research projects follow, along with a listing of all studies during the year. (Table 2) 9 STATION PROJECTS Permanent or long-range projects continued during the fiscal year by station personnel include attention to the gathering of accurate and more varied weather and climatic data. The addition of two hygrothermographs to those previously installed and the transfer of another provide an improved climatic record along an altitudinal gradient through the research center from an elevation of 400 feet, at Living Desert, to 4,000 feet , at Pinyon Flat. An installation was made in early fall, 1974, at the new Pinyon Crest County-State Fire Station, which is on the 4,000-foot contour of the Santa Rosas. The upper elevation site has been moved twice in the past year be- cause of unforseen circumstances. It was removed from the Sugarloaf Store when that pioneer establishment, built by Arthur Nightingale more than 40 years ago, was closed and placed on the real estate market. The equipment later was moved to the Taylor Ranch near the rim of Deep Canyon and now is at the fire station, hopefully permanently. Equipment formerly kept at Bucket 58, the mouth of the inner gorge in Deep Canyon, has been moved to Ironwood Country Club. Instruments there and at Living Desert have been bolstered through the efforts of Colin Wainwright, a UCR graduate student who is conducting the center's Ironwood area ecological study. Mr. Wainwright's summary of his second- quarter findings follows. 10 IRONWOOD ECOLOGY STUDY (Editor's note: This long-range study is financed by Ironwood Country Club and Philip L. Boyd, with administrative support from Deep Canyon. It began Jan. 1, 1974 with $2,500 each from the first two sponsors. Ironwood is a 1,000-acre golf-tennis condominium development at the mouth of Deep Canyon. A major purpose of the study is a comparative examination of native plant and animal life in a natural area altered by land development.) VEGETATION The vegetation in and around Ironwood Golf Course is being studied by a series of transects within and extending out of the course boundaries . In response to irrigation the "desert vegetation" is becoming dense and prolific. A number of native and introduced weedy species , not normally found in this area, are becoming established and increasing in density. MAMMALS Density and reproductive patterns of small mammals (rodents) are being observed in three study areas; 1. An undisturbed desert zone away from the golf course; 2. A desert zone adjacent to the golf course, and, 3. A desert zone within the golf course. In contrast to the area outside the golf course the desert zone within the course shows a sharp increase in rodent populations along with a pro- longed reproductive period. This is probably due to the increase in avail- able water and food reserves brought about by the presence of the golf course. 11 �W BIRDS The changing density of bird species frequenting Ironwood is being studied along a transect extending across the alluvial fan from the mountainous area on the east , through the golf course, including grassy areas , water and sand traps and desert zones within the course boundaries , and across undisturbed desert to the mountainous area on the west. The increase in water and vegetative material from the golf course is having a marked effect on bird populations. There is a definite in- crease in non-desert as well as desert species within the course perimeter as compared to desert areas adjoining it. REPTILES AND AMPHIBIANS Snakes and lizards are being studied in the three small-mammal sites. The density of reptiles is increasing in the desert zones within and around the golf course, in contrast to the desert area outside the golf course. In general the density of amphibians is increasing in the golf course area with permanent water or continual irrigation. ,0 INSECTS Presently insect material is being collected by light-trapping and examined from three locations: 1. Living Desert Reserve; 2. Ironwood Golf Course, and, 3. Boyd Deep Canyon Desert Research Center. Most of these data have not yet been analyzed but mosquito data thus far indicate no significant differences among the three areas. CLIMATE jow Climatic conditions--temperature, humidity and rainfall-- are being monitored at the golf course, Living Desert and at several Deep Canyon sites . 12 A comparison of these data indicate an increase in humidity in the golf course area. This difference in moisture is likely due to the increased irrigation. (Results of this study, if a longterm period is possible, should be useful both to researchers and to desert land developers and will be available in professional journals and special reports on a periodic basis,) 13 ENTOMOLOGICAL SURVEY (Editor 's Note: A continuing faunal survey for insects and related non-insectan arthropods has been one of the major long-range studies at Deep Canyon, virtually from the beginning. It was originated by Dr. . E.I. Schlinger, now at UC Berkeley. Since 1969 the survey has been conducted w by Saul Frommer, Senior Museum Scientist at UCR's Department of Entomology. His summary follows .) This report covers the period of July, 1973-September, 1974. During this time our efforts have been directed to: 1. The continued preparation, identification and storage of hereto- fore collected arthropod materials taken in the Deep Canyon study area. 2. The gathering and processing of additional materials. 3. An updating of the hierarchic checklist of insects and non- insectan arthropods recorded from the study area. 4. Limited continuance of the survey of insect associates of the plant Simmondsia chinensis (Link) Schneider, goatnut or jojoba. 5. Continued research on the dipterous families Bombyliidae, Chamaemyiidae and Chironomidae. During the year approximately 10,000 insect specimens were processed and incorporated into the Deep Canyon collection. We still cannot say that all previously collected materials are evenly basically processed, however. In the next few months I anticipate considerable progress with the assistance of Jeff Smith, recently hired thanks to a $400 grant from Deep Canyon. Much of our specimen backlog consists of past Malaise trap collections in the 1969-1970 period. These originated at the (-)57 marker in the lower canyon near the alluvium. As a byproduct of Ali Tabet's study of the beefly 14 fauna we obtained additional collections from this and several other Deep Canyon study sites. The number of named taxa from the study area continues to grow. For example, in July 1973, the number of families was 291, genera 914, species 1,159 and subspecies 87. In September, 1974, the corresponding totals were 321, 1,026, 1,301 and 96. Increases ranged from 10 to 20 percent. This growth is significant in view of the limited time we have to pursue species determination. Many taxa remain unstudied. Arthropod diversity was further attested to by Tabet's yearlong intensive study, restricted to only two altitudinal levels. Dr. John D. Pinto's summary of Tabet's impressive results follows this report. On March 19, 1974 we completed updating the taxonomic names list. Since then we have added many more names, as well as made many updates for the list. Funds permitting, we recommend annual updating. A site for the Simmondsia arthropod associates study was selected at approximately 2800 feet elevation near Black Hill. The study plot is approximately 38,000 square feet. Ninety-six plants were found, although the majority do not show very vigorous growth. Most collecting was done April 15-19 and arthropod associates appear few in number. Insects no doubt exert some influence on the plants but the extent cannot yet be determined. It is clear that this study requires much time and certainly financial support. Inquiry to date has been quite limited, yet the possible economic value of this plant would indicate a study is worthwhile. We intend to continue our limited survey, feeling that even this cursory glance may prove of value to future researchers. Absence of adequate support for the chamaemyiid study, involving the 15 seasonal fly pest Paraleucopis boydensis Steyskal, is the main factor limiting my comments. I can report that the fly's activity seems to be limited to March, April and May. The fly occurs on the canyon floor, ca 900 feet and has been taken at the 2800-foot level. It would appear to be restricted to this zone but possibly inhabits a somewhat higher elevation. I have not retrieved it on the Cactus Spring Trail, although other flies are pestiferous at this level. A study of the anthropophilic flies of the area should be both challenging and enlightening. Field work on the dipterous family Chironomidae was limited this year, with but a few collections. However , progress is being made on a text treating the Chironomidae of California, including the fauna of Deep Canyon. Several new species taken in the area will be treated. I estimate the number of species of Chironomidae to be found in the study area at around 60 to 65, which was not anticipated when the study began. Tabet, a UCR graduate student, completed a one-year phenological study of the Deep Canyon bombyliid fauna under Dr. Pinto's direction. ,Tack C. Hall of the Division of Biological Control is working on a manu- script treating the beefly fauna from the systematic standpoint. It is fervently hoped that similar studies can be pursued and that further investigations into the biology of the desert-dwelling arthropods of Deep Canyon will be forthcoming. _ 16 SUPPLEMENT An MS thesis entitled "A Phenology Study of the Bombyliidae of Deep Canyon" was completed this year by Ali B. Tabet, comparing the diversity, seasonal distribution and host plant preferences of the beefly fauna at two sites of different elevation within the canyon. It is based on weekly collecting and the maintenance of four Malaise traps during 1973-1974. The diversity and abundance of beeflies in Deep Canyon is extremely high, even for insects , with 32 genera and 158 nominal species wk currently known and numerous additional species yet to be described from collected material. Fully 50 % of the genera and about 20 % of the species described from North America are now known to occur in Deep Canyon. Since the two areas sampled are both in desert zones (1000 and 3000 feet) , the total diversity is expected to be significantly higher when other canyon habitats are fully sampled. This study suggests that periods of maximum beefly occurence are correlated with rainfall and temperature. In general maximum diversity and abundance are bimodal throughout the year, with the highest levels reached before and after the hot summer months , and after periods of maximum precipitation. Although a large number of beefly species occur together in a similar habitat , separation by season, host plant and altitude is pronounced. The diversity of larval hosts supporting this large number of species now becomes an interesting area for future study. John D. Pinto Assistant Professor of Entomology And Assistant Entomologist Division of Economic Entomology 17 DESERT BIGHORN SHEEP Dr. Jack C. Turner of the University of Wyoming, assisted by Margaret Faye (Peggy) Merritt , a UCR student , continued bighorn sheep field studies he began as a UCR graduate student in 1969. Unfortunately, a delay in fund- ing from National Geographic Society and other sources limited the work during the fiscal year to data analysis and publication, with minimal field studies possible. Miss Merritt was accepted as a graduate student by Utah State University at Logan, where she will conduct Rocky Mountain Mule Deer ecological studies. Continuing telemetric and visual monitoring of physiological-behaviorial functions are planned by Turner during the t 1974-1975 fiscal year. N Aw 18 FUTURE NEEDS Several items of repair and improvement for the center's physical plant are included in the request for minor capital improvements for 1975- 1976, now under study with other Riverside campus requests. Where our own limited funds permit we have undertaken some of these improvement with the continued assistance of private donors. The Boyd Center hopes to expand its weather reporting and recording system, both with additional instruments at existing stations and with additional sites. We also require some form of telephonic message recording equipment for use while the station's resident researcher is away from the buildings. This equipment should be capable of transcribing longer messages than most low-cost tape devices on the commercial market. A smaller camera, perhaps 35 mm, would also be useful for field re- search in difficult hiking areas. The station has a splendid Hasselblad camera system but it is bulky as well as delicate. We continue to report a comprehensive need for aerial and ground Nk topographic maps of the entire 14,000-acre center, including the new salamander reserve and other adjoining lands administered by the U.S. Bureau of Land Management. Presently, available topographic maps for the lower, more accessible areas are adequate but detailed large-scale maps for outlying land sections might serve as valuable survey tools for future research, These could be made from precise aerial photographs. Direct financial support for graduate-student research remains one of the most pressing problems for desert biology in general and Deep Canyon in particular. The interest income from the Sperry Memorial Fund is one 19 A possible source of this support. Funds are needed both for long and short term studies , including basic transportation. A more adequate reference library at the station also is a virtual necessity for expanded research. Current studies involving thermoregulation variations among desert rattlesnake species illustrate another need for minor funding. The center has a set of small mammal or reptile temporary holding pens. These are inadequately shaded to protect many species during summer. Insulative walls , movable shades or other heat-reducing devices should be installed. A continuing need for direct acquisition or long-term research permits on privately-owned land interspersing BLM and UC acreage is again reported. Currently, the success of the Natural Land and Water Reserves System fund drive is vital to Deep Canyon's land protection. Private sections in the land ownership checkerboard surrounding Deep Canyon are a problem, both for land security and preservation of habitats-communities for longterm research. JO 4' 20 TABLE 1 TOTAL NUMBER OF PERSONS REGISTERED PER MONTH w July 36 August 31 W. September 35 October 77 November 89 December 32 January 73 February 64 March 64 April 228* May 88 June 37 854 (*-Included 103 students in six classes) F 21 TABLE 2 ORIGIN OF VISITORS TO THE CENTER Universities and research-related institutions: University of California Riverside Los Angeles San Diego Davis Santa Barbara Berkeley Claremont Colleges Pomona Claremont Pitzer Harvey Mudd California State University, Fullerton and Sacramento University of Nevada at Las Vegas Hamilton College, Oswego, N.Y. University of Wyoming Tulane University Phytotron, Paris , France San Diego State University Ae Central Michigan University Portland State University Evergreen State College, Aberdeen, Wash. Australian National University, Canberra University of Tulsa 22 Table 2 continued Museums and conservation organizations Living Desert Association Oregon Museum of Science and Industry Malki Museum Palm Springs Desert Museum Riverside Municipal Museum Southern California Directors of Botanic Gardens and Arboreta Greater San Diego Science Teachers Association Governmental agencies U.S. Bureau of Land Management National Park Service Geological Survey National Weather Service California Departments of Fish and Game, Parks and Recreation Riverside County Departments of Parks and Planning San Bernardino County Parks Department Coachella Valley County Water District Coachella Valley Mosquito Abatement District News media Christian Science Monitor Palm Springs Desert Sun Riverside Press-Enterprise 23 Table 2 continued Commercial organizations: Chalfont Communications General Telephone and Electronics S & L Construction Co. Petrolane White's Custom Electric Anza Electric Cooperative 4. 10 24 TABLE 2A CLASS OR GROUP VISITS TO THE CENTER 1973-1974 University of California, Riverside Vertebrate field biology, April 13-14 Instructor: Wilbur Mayhew, 17 persons. University of California, Riverside Field entomology, four visits , April, May. Instructor: John Pinto. 7 persons. University of California, Santa Barbara Field botany, April 6. Instructor: Robert Haller. 55 persons. University of California, Los Angeles Plant geography, April 21. Instructor: Jonathan Sauer. 4 persons. Pomona College, Claremont Ecology of Vertebrate Communities, April 19-21. Instructor: William Wirtz, 16 persons, California State University, Sacramento Field Biology, May 5, 1974. Instructor: Michael Baad. 14 persons. Oregon Museum of Science and Industry, Portland. The Sonoran Desert, Jan. 10-11. Instructor: Mike Uhtoff, 18 persons. Living Desert Park Interpretive Specialists Conference Seminar, April 8. Leader: Karen Fowler, 12 persons, Greater San Diego Science Teachers Association Desert Field Trip, April 20. Coordinator: William Reich. 38 persons. 1F Natural Land and Water Reserves System Committee Fall conference, October 26, Roger Samuelsen, coordinator. 27 persons. Southern California Botanical Gardens Directors Living Desert seminar, March 29. Coordinator: Paul Shaw. 12 persons. 25 TABLE 3 RESEARCH PROJECTS Wirtz, William 0. Pomona College, Ecology of ground squirrels, Lang, Anna. UCLA. Geographic patterning of desert vegetation, Turner, Jack C. University of Wyoming. Physiology and behavior of desert bighorn sheep. Wainwright, Colin. UCR. Ironwood ecology study, Moore, Robert, UCD, Thermoregulation in three species of desert rattlesnakes. Moore, Beatrice. UCD, Thermoregulation in Bufo punctatus, Zabriskie, Nancy, UCR-Deep Canyon. Plant collection. Fr.ommer, Saul. (and others) UCR. Arthropod faunal survey. (More time is spent working on the collection at UCR.) Ting, Irwin P. , Bruce Sutton and Stanley R. Szarek, UCR. Cactus physiology studies (various), Johnson, Hyrum, UCR. Ecology-physiology of desert plants. Ting, Irwin P. and Barry Osmond. UCR-ANU. Comparative. cactus survey, Arizona and Deep Canyon, Mayhew, Wilbur (Andy Sanders, Phil McNally, Emily McGregor and Toni Gull, students) , UCR. Bird survey of Deep Canyon, Tabet, Ali. UCR . Phenology of beeflies (Dip: Bombyliidae) , Gordon, Susan. UCB. Competition for food between ants and vertebrates, Bernstein, Ruth. UCLA, Behaviorial measurements of ant colonies. Lacey, Lawrence, UCR. Bat nesting sites , simuliid survey. Man kau, R. (and others) , UCR. Biology of nematodes in desert ecosystems, Cowles , Raymond B. , UCSB. Mistletoe vector survey, Fonteyn, Paul. UCSB. Physiological adaptations of ocotillo and creosote bush, 26 Table 3 continued Krout , Douglas. SDSU. Non-symbiotic bacterial nitrogen fixation in desert soils. (completed MS thesis.) Hodson, Robert and Richard Lee. UCSD. Tarantula survey. Schuster, Robert. UCSB. Arthropod survey. Mulla, Mir. UCR . Mosquito survey. McClanahan, Lon. CSUF. Desert toad survey. Brownell, Philip. UCR. Predatory behavior of solpugids and scorpions. Coachella Valley Mosquito Abatement District. Routes, migration and populations of desert mosquitoes. Coachella Valley County Water District. Subsurface hydrology. U.S. Geological Survey. Garden Grove. Stream hydrology. yr 27 TABLE 3A PERSONS AND RESEARCH AT DEEP CANYON FINANCED BY DEEP CANYON RESEARCH FUNDS DURING 1973-1974 FISCAL YEAR Frommer, Saul (and others) Arthropod faunal survey. Continuing from 1963. Preliminary taxonomic list published 1974. Turner, Jack C. Physiology and behavior of desert bighorn sheep. Continuing from 1969. Also supported by Palm Springs Atajo and National Geographic Society. Wainwright, Colin. Ironwood Ecology Survey. Also supported by Ironwood Country Club (Silver Spur Associates) and Philip L. Boyd. Zabriskie, Nancy. Deep Canyon plant collection. Sutton, Bruce. Studies on the carbohydrate metabolism of cactus in a native environment. (ANU postdoctoral fellow) Szarek, Stanley. Physiological mechanisms of drought adaptation in 0 up ntia basilaris Engelm. & Bigel. Completed dissertation and other requirements for Ph.D. degree. Also supported by Desert Biome, International Biological Program (NSF) . ` ` 28 TABLE 4 LIST OF PUBLICATIONS AND DISSERTATIONS , 1972-1974* 1972 Bradshaw, S.D. , V.H. Shoemaker and K.A. Nagy. 1972. The role of adrenal corticosteriods in the regulation of kidney function in the desert lizard Dipsosaurus dorsalis. Comp. Biochem. Physiol. , 1972 43(A): 621-635. Cowles , Raymond B. 1972. Mesquite and mistletoe. Pacific Discovery, 25(3) : 19-24. Lynch, Timothy, Rodolfo Ruibal and Lloyd Tevis. 1972. Birds of cattle feedlots in Riverside County, California, Dept. Biology and Boyd Research Center, UCR. (Mimeographed for distribution and subsequent publication California Agriculture, 1973 27(3): 4-6, and Western Livestock Journal (new title: Birds ingrained in feedlot economics) 1973 52(5). Oechel, W.C. , B.R. Strain and W.R. Odening. 1972. Photosynthetic rates of a desert shrub, Larrea divaricata Cay. , under field conditions. Photosynthetica, 6(2) : 183-188. . 1972. Tissue water potential, photosynthesis , 14C labeled photo- sythate utilization and growth in the desert shrub Larrea divaricata Cay. Ecological Monographs, 42: 127-141. Shoemaker , V.H. , K.A. Nagy and S.D. Bradshaw. 1972. Studies on the `tiff control of electrolyte secretion by the nasal gland of the lizard Dipsosaurus dorsalis. Comp. Biochem. Physiol. , 1972. 42(A) : 749-757. * Not previously in annual reports or publication lists. 29 Table 4 continued 1972 (cont'd) Ting, Irwin P. , Hyrum B. Johnson and Stan R. Szarek. 1972. Net CO2 fixation in crassulacean acid metabolism plants. Net carbon dioxide assimilation in higher plants, a symposium, C.C. Black, editor. Amer. Soc. of Plant Physiologists (So. Sec.). 1972. Proceedings, pp 26-53. Dissertations MacKay, William P. 1972. Home range behavior of the Banded Rock Lizard, Petrosaurus mearnsi. MS thesis , California State University, Fullerton. 1973 Alexander, C.P. 1973. Undescribed species of Nearctic Tipulidae (Diptera). Great Basin Naturalist, 33(3) : 189-196. (Description of Ti ula (Trichotipula) frommeri Alexander, a new species of Tipulidae from Deep Canyon.) Staff. 1973. Floristic list for Deep Canyon watershed. P.L. Boyd Deep Canyon Desert Research Center, University of California, Riverside. October. 28 pp. Steyskal, George C. 1973. The genera of the family Thyreophoridae and the species of the genus Omomyia with one new species (Diptera) . Ann. Ent. Soc. Amer. , 66(4) : 849-852. Szarek, Stan R. , Hyrum B. Johnson and Irwin P. Ting. 1973. Drought adaptation in Opuntia basilaris. Plant Physiol. , 52: 539-541. Ting, I.P. 1973. Carbon metabolism in plants. What 's New in Plant i Physiology, 5(3) : 4 pp. 30 Ting, I.P. , Hyrum Johnson and Stan R. Szarek. 1973. Gas exchange and productivity for 0 up ntia spp. Intl. Bio. Program Conf. (Wales) , Proc. Ting, I.P. 1973. Physiological adaptation to water stress in desert plants. Am. Inst. Bio. Sc. , Physio. Adapt. Symp. Proc. Wheeler, G.C. and Jeanette Wheeler. 1973. Ants of Deep Canyon. P.L. Boyd Deep Canyon Desert Research Center, University of California, Riverside. 162 pp. Dissertations Turner, Jack C. 1973. Water, energy and electrolyte balance in Desert Bighorn Sheep (Ovis canadensis). Ph.D. dissertation, University of California, Riverside. 1974 Staff. 1974. Bird list for Boyd Center and Deep Canyon transect. Philip L. Boyd Deep Canyon Desert Research Center, University of California, Riverside. 13 pp. 1974. Arthropod checklist for Deep Canyon. Philip L. Boyd Deep Canyon Desert Research Center, UCR. 78 pp. Szarek, Stan R. and Irwin P. Ting. 1974. Seasonal patterns of acid metabolism and gas exchange in 0 up ntia basilaris. Plant Physiol, (1974) 54: 76-81. . Respiration and gas exchange in stem tissue of Opuntia basilaris. Plant Physiol. (In Press) . . Physiological responses to rainfall in 0 untia basilaris. American Journal of Botany. (In Press). 31 rr Table 5 continued Dissertations and student papers Krout, D. J. 1974. Non-symbiotic bacterial nitrogen fixation in desert soil. MS thesis , San Diego State University. Merritt , Margaret Faye. 1974. Measurement of utilization of bighorn sheep habitat in the Santa Rosa Mountains. A senior paper reporting on the Turner sheep study. University of California, Riverside. Sanders , Andy, Toni Gull, Emily McGregor and Phil McNally. 1974. Bird transects study in the Deep Canyon area, Santa Rosa Mountains. Extensive class paper used as basis for Deep Canyon bird list. Szarek, Stanley R. 1974. Physiological mechanisms of drought adaptation in Opuntia basilaris , Engelm. & Bigel. Ph.D. dissertation, University of California, Riverside. Tabet, Ali Basher. 1974. A phenology study of the Bombyliidae of Deep Canyon. MS thesis. University of California, Riverside. Wainwright , Colin. 1974. Ironwood ecological study, a preliminary report. Philip L. Boyd Deep Canyon Desert Research Center, University of California, Riverside. 8 pp. 32 77 77 s s^6; o e �r '.. � Ee+ z Y "fe w q 40# P4"A C 1 � ' 7 t t�q a { s w i f DRAFT REPORT City of Palm Desert Seismic Safety Element Technical Report 1 written pcu;h Draft Repor The This i� a ,, ;. �.a�;ess• ry 4 pd to rv:• V41 Cj'%li nod d Vol ei _ i t, r�^-�. ✓ i or suggesbons "i be 4rrrc.� `tNVICOM CORPORATION prepared by ENVICOM CORPORATION September, 1974 I i a This report is copyrighted and cannot be reproduced in .vi,:o;e or in part without the written cons.-nt of UMCOM Corporation. i CONTENTS I INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. Scope of Investigation . . . . . . . . . . . . . . . B. Philosophy of the Analysis . C. Concepts, Methodology and Terminology . . . . . . . . . . . . 1 . General Statement. . . . . . . . . . . . . . . . . . . . . . . . . 2. Types of Hazards . . . . . . . . . . . . . . . . . . . . . . . . . 3. Active Faults — The Source of Earthquakes . . . . . . . . 4. Describing an Earthquake . . . . . . . . . . . . . . . . . . . 5. Occurrence, Recurrence and Risk of Earthquakes . . . 6. Acceleration, Velocity and Displacement. . . . . . . . . . 7. Frequency Content — Fourier and Response Spectra. . . 8. Near-Surface Amplification. . . . . . . . . . . . . . . . . . . D. Responsibility for Seismic/Geologic Hazard Evaluation II ANALYSIS OF SEISMIC HAZARDS . . . . . . . . . . . . . . . . . . . A. Geologic and Seismic Setting . . . . . . . . . . . . . . . . . . . . B. Faulting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. A ctive Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. San Andreas Fault . . . . . . . . . . . . . . . . . . . . . . . . . 3. San Jacinto Fault . . . . . . . . . . . . . . . . . . . . . . . . . 4. RecurrenVIntervals for the San Andreas and jSan Jacinto Faults . . . . . . . . . . . . . . . . . . . . . . . . ( 5. Concealed Faults on the Southwest Side of the Coachella Valley . . . . . . . . . . . . . . . . . . . . . . . . 6. Potential for Sympathetic Movement . . . . . . . . . . . . 7. Summary of Faulting . . . . . . . . . . . . . . . . . . . . . . . C. Earthquake Shaking . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Sources of Expected Shaking . . . . . . . . . . 2. Intensity of Recorded Earthquakes . . . . . . 3. Engineering Characteristics of Expected Earthquakes . ( 4. Comparison of Predicted and Observed Shaking . . . . . ID. Secondary Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Settlement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Liquefaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Landslides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. Tsunamis and Seiches . . . . . . . . . . . . . . . . . . . . . . . . CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LIST OF ILLUSTRATIONS ii t Figure Page 1 Acceleration, velocity and displacement, 1966 Parkfield earthquake . . . . . . . . . . . . . . . . . . 2 Acceleration, velocity and displacement, 1971 San Fernando earthquake . . . . . . . . . . . . . . . 3 Fourier and response spectra, 1952 Kern Countyearthquake . . . . . . . . . . . . . . . . . . . . . . 4 Response spectra, 1966 Parkfield earthquake . . . 5 Response spectra, 1962 Mexico City earthquake 6 Geologic index map of Palm Desert and vicinity . . . . 7 Map showing location of earthquake epicenters, 4, 0 and greater, 1932-1972, Southern California region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Map showing location of earthquake epicenters, 5. 0 and greater, 1932. • • - .1972, Southern California region • 9 Map showing location of earthquake epicenters, 6. 0 and greater, 1932-1972, Southern California region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 10 Geometry and mathematics of computation of the engineering characteristics of an earthquake , . • • . 11 Diagrammatic geologic cross section . . . . . . . . . . . l 12 Amplification spectrum for b.edrock site condition with 25 feet of weathered material over hard rock , 113 Amplification spectrum for 60 feet of alluvium over hard bedrock . . . . . . . . . . . . . . . . . . . . . . . 14 Amplification spectrum for 200 feet of alluvium over hard bedrock . . . . . . . . . . . . . . . . . . . . . . . 1 15 Amplification spectrum for 500 feet of alluvium overhard bedrock . . . . . . . . . . . . . . . . . . . . . . . 16 Amplification spectrum for 1000 feet of alluvium over hard bedrock . . . . . . . . . . . . . . . . . . . . . . . 17 Response spectra of one component of the El Centra record of the 1940 Imperial Valley earthquake , LIST OF ILLUSTRAIONTS (cont) Figure Page 18 Response spectra of one component of the Taft record of the 1952 Kern County earthquake . . . . . . 19 Response spectra, type 1. . . . . . . . . . . . . . . . . . . 20 Response spectra, type 2. . . . . . . . . . . . . . . . . . . 21 Response spectra, type 3. . . . . . . . . . . . . . . . . . . 22 Response spectra, type 4. . . . . . . . . . . . . . . . . . . 23 Response spectra, type 5. . . . . . . . . . . . . . . . . . . 24 Response spectra, type 6. . . . . . . . . . . . . . . . . . . 25 Response spectra, type 7. . . . . . . . . . . . . . . . . . . 26 Response spectra, type 8. . . . . . . . . . . . . . . . . . . 27 Response spectra, type 9. . . . . . . . . . . . . . . . . . . 28 Response spectra, type 10 . . . . . . . . . . . . . . . . . . 29 Response spectra, type 11 . . . . . . . . . . . . . . . . . . 30 Response spectra, type 12 . . . . . . . . . . . . . . . . . . 31 Response spectra, type 13 . . . . . . . . . . . . . . . . . . 32 Response spectra, type 14 . . . . . . . . . . . . . . . . . . 33 Response spectra, type 15 . . . . . . . . . . . . . . . . . . 11 34 Response spectra, type 16 . . . . . . . . . . . . . . . . . . 35 Response spectra, type 17 . . . . . . . . . . . . . . . . . . 36 Response spectra, type 18 . . . . . . . . . . . . . . . . . . 37 Example of a rockfall type' of landslide . . . . . . . . . i i 1 I LIST OF TABLES i I Table Page t. 1 Modified Mercalli Intensity Scale of 1931 . . . . . . . . . 2 Distribution of responsibility for evaluation of seismic/geologic hazards . . . . . . . . . . . . . . . . . . 3 Summary of recent earthquakes of intensity V or greater at Palm Springs . . . . . . . . . . . . . . . . . 4 Generalized characteristics of expected earthquakes 1 i i i t i I INTTRODUCTIO-NT A. SCOPE OF INVESTIG_<1TION I Section 65302 (f) of the Government Code requires a Seismic Safety Element of all city and county general plans as follows: 1 "A seismic safety element consisting of an identification and appraisal of seismic hazards such as susceptibility to surface ruptures from faulting, to ground shaking, to ground failures, or to the effects of seismically induced waves such as tsunamis and seiches. The seismic safety element shall also include an appraisal of mudslides, landslides, and slope stability i as necessary geologic hazards that must be considered simultaneously with other hazards such as possible sur- face ruptures from faulting, groundshaking, ground failure and seismically induced waves. " The Guidelines (California Council on Intergovernmental Rela- tions, 1973) for the preparation of local general plans states that: "The intent is that all seismic hazards are to be con- sidered, even though only ground and water effects are given as specific examples. The basic objective is to reduce loss of life, injuries, damage to property, and economic and social dislocations resulting from future earthquakes. " Based on the interpretation of the intent of the law, the Guidelines define the scope of the Element as including: 1 . A general policy statement. 2. The identification, delineation and evaluation of natural ! seismic hazards. ! 3. The consideration of existing structural hazards. 4. An evaluation of disaster planning program. 5. The determination of specific land use standards related to level of hazard and risk. f The Guidelines indicate that the identification of natural seismic hazards should include the following: " 1. General structural geology and geologic history. 2. Location of all active or potentially active faults, with evaluation regarding past displacement and probability of future movement. 3. Evaluation of slope stability, soils subject to liquefaction and differential subsidence. I4. Assessment of potential for the occurrence and severity of damaging ground shaking and amplifying effects of unconsolidated materials. 5. Identification of areas subject to seiches and tsunamis. 6. Maps identifying location of the above characteristics. " I iThe following technical evaluation is intended to meet or exceed these requirements. B. PHILOSOPHY OF THE ANALYSIS The quantitative study of the strong shaking of earthquakes is a relatively young science. It was begun in California in the early 1930's, but has been limited by the necessity of having the right instruments in the right place when a significant earthquake does occur. Much information has been acquired over the last 40 years, but there are significant gaps and much remains to be Ilearned. With this relatively limited level of basic data, two different approaches to the development of a Seismic Safety Element are available. One can utilize broad generalizations to describe expected events: certainly the inadequacies of the data favor this approach. On the other hand, if the results are to be used by engineers in designing safer structures, then a commitment to mathematical form is necessary. To this end, the analysis is developed in this way, whenever possible, and presented in chart or graph form. Qualitative descriptions of the results are included for the lay reader, and a brief discussion of meth- odology, terminology and concepts is included in Section C.1 A Glossary of Terms for reference purposes is included at the back of the report. The basic philosophy within which this analysis has been i developed is that the intent of the Seismic Safety Element is to plan and prepare for the future based on what we know today rather than waiting until we know all that we would like to know. C. CONICEPTS, METHODOLOGY AND TERMINOLOGY r1. General Statement The Seismic Safety Element is probably the most technically- oriented of all the mandated elements of the General Plan. For this reason, and because of the wider range of backgrounds and experience of expected readers, it is appropriate to include in the Introduction a discussion of concepts, methodology and termi- nology to be used in developing the technical base for this ele- ment. This discussion is intended to supply not only a dictionary- function of technical terms and concepts, but, most important, to establish the systematic cause-and-effect relationships between the several seismic hazards, and the need for a systematic analysis of available information. The topics discussed in the following sections of the intro- duction are arranged in an order that becomes increasingly more difficult for the layman. Sections Z through 4 discuss concepts and terms commonly included in newspaper accounts of earth- quakes, while later sections discuss the concepts necessary in the technical analysis of earthquake hazards. The latter are intended primarily for readers with engineering or scientific backgrounds, but may also be of interest of the lay reader. The text of the report is arranged in a similar order. Each section becomes increasingly more complex, and the later sec- tions are intended to document the analysis for engineers and earth scientists who may wish to expand on or apply the data to the detailed analysis of individual sites. Z. Types of Hazards The several seismic hazards discussed in the C. I. R. Guide- lines can be grouped as a cause-and-effect classification that is the basis for the order of their consideration. Earthquakes originate as the shock wave generated by movement along an active fault. The primary natural hazards are ground shaking and the potential for ground rupture along the surface trace of the fault. Secondary natural hazards result from the interaction L- I i of ground shaking with existing ground instabilities, and include liquefaction, settlement and landslides. In this context, tsu- namis, or "tidal waves", and seiches would be primary natural hazards. The potentially damaging natural events (hazards) discussed above may interact with man-made structures. If the structure is unable to accommodate the natural event, failure will occur. The potential for such failure is termed a structural hazard, and includes not only the structures themselves, but also the potential for damage or injury that could occur as the result of movement of loose or inadequately restrained objects within, on, or adjacent . to a structure. 3. Active Faults — The Source of Earthquakes Earth scientists are generally agreed that earthquakes origi- nate as the result of an abrubt break or movement of the rock in t the relatively brittle crust of the earth. The earthquake is the 1 effect of the shock waves generated by the break, much the same as sound waves (a noise) are generated by breaking a brittle stick. If the area of the break is small and limited to the deeper part of the crust, the resulting earthquake will be small. However, if the break is large and extends to the surface, then the break can result in a major earthquake. These breaks in the earth's crust are called faults. In California, faults are extremely common, and vary from the small breaks of an inch or less that can be seen in almost any road-cut, to the larger faults such as the San Andreas on which movement over many millions of years has amounted to hundreds - of miles. In addition to the size of faults, their "age" is also important. Many large faults have not moved for millions of years; they are considered "dead" or no longer active. They were probably the source of great earthquakes millions of years ago, but are not considered dangerous today. Since faults vary as to the likelihood of their being the source of an earthquake, considerable effort has, and is continuing to be expended by geologists and seismologists to determine and deline- ate the faults likely to generate significant earthquakes. The C. I. R. Guidelines define an active fault as one that "has moved in recent geologic time and which is likely to move again in the relatively near future. Definitions for planning purposes extend I on the order of 10, 000 years or more back and 100 years or i i The above discussion applies directly to Special Studies Zones as required by the Alquist-Priolo Act. To date no such zones have been established within the City of Palm Springs. However, the State Geologist is required to "continually review f new geologic and seismic data" in order to revise established ` zones and to delineate additional zones. In this context, evidence of fault activity in the Palm Springs area will be discussed herein utilizing the framework of evaluation as provided by the State Geologist and the State Mining and Geology Board. Additional comment on the responsibility for evaluation of geologic/seismic hazards is included in Section Dof this Introduction, and also as pertinent in that part of the text covering the, evaluation of active and potentially active faults. 4. Describing an Earthquake q Several terms are used to describe the location, "size", and effects of an earthquake. A clear understanding of the meaning of these terms and their limitations is essential to an understanding of the results of the investigation. The location of an earthquake is generally given as the epicenter of the earthquake. This is a point on the earth's sur- face vertically above the hypocenter or focus of the quake. The latter is the point from which the shock waves first emanate. l However, as discussed above earthquakes originate from faults. These are surfaces not points, so the hypocenter is only one point on the surface that is the source of the earthquake. Magnitude describes the size of the earthquake itself. Tech- nically it is defined as the log of the maximum amplitude as recorded on a standard seismograph at 100 kilometers (62 miles) from the epicenter. The most important part of this definition is that it is a log scale: that is, an increase of 1 on the magnitude scale (e. g. magnitude 5. 0 to 6. 0) represents an increase of 10 in the amplitude of the recorded suave. Intensity describes the degree of shaking in terms of the damage at a particular location. The scale used today is the Modified Mercalli Scale of 1931, and is composed of 12 cate- gories (I to XII) of damage as described in Table 1. The Roman numerals are used to emphasize that the units in the scale are descrete categories rather than a continuous numerical sequence as is the magnitude scale. It is important to remember that intensity is a very general description of the effects of an L more forward. " In this definition, "has moved" would normally IIbe taken to mean demonstrable movement at the surface. I The State Mining and Geology Board (1973), for purposes of the Alquist-Priolo Geologic Hazards Zone Act (Chapter 7. 5, Division 2, Public Resources Code, State of California) "regards faults `which have had surface displacement within Holocene time (about the last 11, 000 years) as active and hense as constituting a potential hazard. " The State Geologist (Slosson, 1973, Explanation of Special Studies Zones Maps, p, 3 & 4) defines a potentially active fault as one "considered to have been active during Quaternary time (last 3, 000, 000 years) -- on the basis of evidence of surface displacement. " The State Geologist notes the contrast with the State Mining and Geology Board, but also states: "An exception is a Quaternary fault which is determined, from direct evidence, to have become inactive before Holocene time (last 11, 000 years). " The definitions above are compatable if taken in the Ifollowing sequence: 1. A potentially active fault is one which exhibits evidence of surface displacement during Quaternary time (last 3, 000, 000 years approximately). 2. A potentially active fault will be considered as an active fault if there is evidence of surface displacement during { Holocene time (last 11, 000 years, approximately). 3. A potentially active fault will be considered as inactive if, - by direct evidence, it can be shown that there has been no displacement during Holocene time. 1 The key to the practical application of the above definitions is the placement .of the burden of proof. The State Geologist will ( consider a fault as potentially active if there is evidence of sur- face displacement during Quaternary time. If a fault is so designated as required by the Alquist-Priolo Act, then the bur- den of proof shifts to the developer to show by "direct evidence" that the fault has not been active (i. e. no surface displacement) during Holocene time. The practical application of this system of evaluation will depend primarily on the interpretation of "direct evidence" in the review and evaluation of the required geologic reports. TABLE 1. MODIFIED IMERCALLI INTENSITY SCALE OF 1931 (from United States Earthquakes) i Intensity Description of Darnage I Not felt except by a very few under specially favorable circumstances. (I Rossi-Forel Scale) II Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing.(I to 11 Rossi-Fore!Scale) I[I Felt quite noticeably indoors, especially on upper floors of buildings,but many people do not recognize it as an earthquake. Standing motorcars may rock slightly. Vibration like passing of truck. Duration estimated. (III Rossi-Fore(Scale) IV During the day, felt indoors by many, outdoors by few. At night, some awakened. Dishes, windows, doors disturbed; walls make creaking sound. t Sensation like heavy truck striking building. Standing motorcars rocked noticeably.(IV to V Rossi-Forel Scale) I V Felt by nearly everyone, many awakened. Some dishes, windows, etc., broken; a few instances of cracked plaster; unstable objects overturned. Disturbances of trees, poles, and other tall objects sometimes noticed. Pendulum clocks may stop.(V to VI Rossi-Forel Scale) l VI Felt by all, many frightened and run outdoors. Some heavy furniture moved; a few instances of fallen plaster or damaged chimneys. Damage j slight. (VI to Vll Rossi-Forel Scale) Vil Everybody runs outdoors. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary strictures; considerably in poorly built or badly designed structures; some chimneys broken. Noticed by persons driving motorcars. (VIll Rossi-Forel Scale) Vill Damage slight in specially designed structures; considerable in ordinary, substantial buildings, with partial collapse;great in poorly built structures. l Panel walls thrown out of frame structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned. Sand and mud ejected in small amounts. Changes in well water. Persons driving motorcars disturbed.(Vlll to IX Rossi-Forel Scale) IX Damage considerable in specially designed structures;well-designed, frame structures thrown out of plumb;great in substantial buildings, with partial collapse. buildings shifted off foundations.Ground cracked conspicuously. Underground pipes broken.(IX Rossi-Forel Scale) X Some well-built wooden structures destroyed; most masonry and frame t structures destroyed with their foundations; ground badly cracked. Rails bent. Landslides considerable from river banks and steep slopes. Shifted sand and mud. Water splashed (slopped)over banks.(X Rossi-Forel Scale) Xi Few, if any, (masonry) structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipelines completely out of service. Earth slumps and land slips in soft ground. Rail, bent greatly. X11 Damage total. Waves seen on ground surfaces. Lines of sight and level distorted. Objects thrown upward into air. 1 earthquake, and depends not only on the size of the quake and the distance to its center but also on the quality of the construction that has been damaged and the nature of local ground conditions. 5. Occurrence, Recurrence and Risk of Earthquakes Earthquakes have had in the past a certain occurrence in space and time. These occurrences may or may not set certain patterns that can form the basis for predicting their occurrence in the future. When such occurrences are analyzed in time, certain characteristics may statistically recur at definite inter- vals. If it can be shown that a particular magnitude earthquake recurrs on a fault on the average of once in a certain time inter- val, then that interval is said to be the recurrence interval for that magnitude. Or, if the interval of time is set (e. g. a 100- year period), then earthquakes of a particular magnitude may recur a certain number of times in the specified period. This number is then the recurrence rate for that magnitude. In California small earthquakes occur much more often than large earthquakes. Also, there is a fairly definite pattern in that the log (base 10) of the number of events of a particular mag- hitude that have occurred in the part is approximately proportional to the magnitude of those events. This relationship appears to apply to larger areas such as California and western Nevada, some smaller areas such as the Los Angeles Basin, the Imperial Valley, etc. , and to some faults. However, this rely tionship does not necessarily apply to all faults, and it should be applied to small areas, such as cities or individual sites, with great care. LRecurrence intervals can be used to' indicate the risk of an earthquake in much the same way that recurrence is used to i describe the risk of flooding (e. g. 100-year flood). There is one important difference, however. Flood is the result of a random combination of meteorological events, whereas current geologic theory indicates that the buildup of the strain released during an earthquake is more likely to be regular. This regu- larity suggests that prediction, to varying degrees, may be j possible depending on the extent of understanding of a particular fault. In some cases this understanding is limited to a statisti- cal regularity in the number and magnitude of earthquakes gen- erated. For others, such as the San Andreas fault, much more is known on which to base an estimate of the risk in- volved. For others, little more is known other than that there is some degree of hazard involved. L 6. Acceleration, Velocity and Displacement The data of seismologists and geologists are, in general, not applicable to the engineering design of earthquake-restraint structures. The seismograph, for example, is a very sensitive: instrument designed to record earthquakes at great distances. A level of shaking that would be meaningful to an engineer in designing a building would put most seismographs completely off-scale. As a result, it has been necessary to design and install special instruments to record the strong motions of earthquakes that are of interest to the engineer in the design of earthquake- restraint structures. The first such instruments, principally accelerographs and seismoscopes, were installed by the U. S. Coast and Geodetic Survey in the late 1920's. Since that time, j the instrumentation and analytical techniques have been i continuously improved, and many excellent records have been obtained of the more recent strong earthquakes. I i The following sections are a brief introduction to the con- cepts, data and application of strong-motion records. The science is relatively young, and is growing in bursts that follow the recording of a damaging earthquake. The accelerograph is a short-period instrument (in contrast ` to the seismograph), and measures the acceleration of the ground ' or the structure on which it is mounted. Figure 1 shows the ground acceleration recorded just a few hundred feet from the slipped fault during the 1966 Parkfield earthquake. The velocity and displacement curves have been derived from it by integration. It is particularly good example of the relationships of these three parameters of motion because of the relatively "clean", single- displacement pulse that corresponds to two velocity peaks and four acceleration peaks. Figure 2 shows the more typically com- plex record of the San Fernando earthquake as recorded at Pacoima Dam. Neither of the two, however, are typical records in terms of accelerations recorded. The Pacoima record shows the largest acceleration recorded to date ( l. 25g), and the Park- field record (0. 5g) was the largest recorded in the United States 1 . before the San Fernando earthquake. It should also be noted that accelerographs normally record three components; two in the horizontal plane at a right angle to each other, and one vertical. Only one component is shown in each of the two examples. �p O{ N 1fl 10 az a vO 'vim" ti�1��� } /1(�V Y (' \ /V `�J �/" V �`� �✓ 4 • . Q-0.2 cz�-O:i .. 40 F � _ V O O J C3,20 _ O (L - _N _ z o� c - -12 - • O z i 6 6 10 IZ 14 TIME.SECZWOS Station 2 N65E Motion. Figure 1. Ground acceleration, velocity and displacement. 1966 Parkfield earthquake. from Housner Trifunac, 1967. I �000 GROUND ACCELERATION N I I{ , It ;} I I � w 1t 1roo t t 1 0 3 10 IS l f00 GROtI?ii) VELOCITY E u - i^ _ 50 100 r 1 1 - 1 t 0 5 10 15 50 - - GRCU?i0 DISPLACE IFNT ,u 50 1 O t 3 10 15 SEMG S' . Figure 2. Acceleration, velocity and displacement in the S16 ° E direction during the main event of the San Fernando earthquake of February 9, 19713, 06:00 (PST). from Trifunac & Hudson, 1971. i Maximum acceleration is one of the basic parameters describing ground shaking, and has been the one most often re- quested by agencies such as FHA in determining the earthquake hazard to residential structures. It is particularly important for "lo­,v-rise" construction (up to 3 to 5 stories) and other structures having natural periods in the range of 0. 3 - 0. 5 seconds or less. 7. Frequency Content - Fourier and Response Spectra The frequency content of the ground motion is particularly important for the intermediate and higher structures. The prob- lem can be compared to pushing a child in a swing. If the pushes are timed to coincide with the natural period of the swing,. then ( each push makes the swing go higher. However, if the timing is not right, then most of the push is lost "flighting" the natural period of the swing. The situation is similar during earthquakes. ( Structures have certain natural periods of vibration. If the pulses of the earthquake match the natural period of the structure, even a moderate earthquake can cause damaging movement. However, if the match is poor, the movement and resulting damage will be much less. Two methods are commonly used to analyze and display the frequency content of an earthquake. A Fourier analysis is a common mathematical method of deriving the significant fre- quency characteristics of a time-signal such as the record of an earthquake. The results of the analysis are an amplitude term and a phase term. The amplitude is normally plotted against the period for the amplitude to give a Fourier amplitude spectrum for the range of frequencies that are of interest. Since the mathematical procedure is basically an integration of accelera- tion with time, the Fourier amplitude has the units of velocity. f A response spectrum is derived by a similar mathematical process, but is slightly different in concept. It represents the maximum response of a series of oscillators, having particular periods and damping, when subjected to the shaking of the earthquake. The result is also expressed in units of velocity with the particular nomenclature depending on the precise method used to derive the spectrum. The Fourier spectrum can be generally described as the energy available to shake structures having various natural frequencies. The response spectrum gives the effect, in maxi- mum velocity, of this available energy on simple structures I having various frequencies and damping. At zero damping the two are very similar. Figure 3 shows a plot of both the Fourier spectrum and the response spectrum with zero damping for the Taft earthquake of 1952. Figure 4 shows the response spectrum for the Parkfield record (Figure 1) for several levels of damping. 8. Near-Surface Amplification The shock waves of an earthquake radiate outward from the source (i. e. the slipped fault) through the deeper and relatively more dense parts of the earth's crust. In this medium, the Iwaves travel at high velocity and with relatively low amplitude. However, as they approach the surface, the velocity of the medium decreases and may become quite variable if layers of different rock types are present. The overall effect is generally an amplification of the wave or of certain frequencies within the spectrum of the wave. The most consistently applicable effect is the increase in wave amplitude that accompanies the decrease in velocity. This j relationship can be compared to laves of mechanics that require the conservation of energy and momentum. In the case of earth- quake waves, the energy of velocity is transferred to energy of wave amplitude when the velocity decreases. I A second effect is the amplification of certain frequencies due to the thickness and velocity of near-surface layers of the earth. The geometry of these layers controls the frequency of shaking just like the geometry of a TV antenna controls the fre- quency it receives best. A striking example is the very high amplification of waves of 2. 5-second period (Figure 5) by the stratification of the old lake beds on which Mexico City has been built. This concentration of the energy in a very narrow fre- quency range could be disastrous for structures with a matching natural period. Just like the child in the swing, they would move more and more with each successive pulse of the quake. Such pronounced amplifications are unusual, but if present, they can be extremely important. D. RESPONSIBILITY FOR SEISMIC/GEOLOGIC I HAZARD EVALUATION The responsibility for the evaluation of seismic and geologic hazards lies with both the public and private sectors. The follo:v- ing are suggested as guidelines in determining the distribution of responsibility of the two sectors; L i tLI ru � c .� LCI l / N H ON I � U ` � o cu I •o�sJ 3 rs;n nc!o� »no-j I Ico PARKF1cLD EARTHQUAKE,JUKE 19&& CHOLAME SH;,ND04-ARRAY STAT ION NO. 2 N65E a� SQL, REL.9FlYE R£SPC�SSE SP'ECffitl4t- \ Sd •p19AtACF %T''I£C'f7K7►f - c t V� SO ul _ 0 1 2 3 4 PERIOD T, SECON1 Figure 4. Response spectra, 1966 Parkfield earthquake. The curves are for 0, 2, 5 and 10/o damping. from Housner & Trifunac, 1967. I i { t . cn ' (an jK ZIP •fj N r v a � v lzi < tt . r} lQ U+ p O 0 � � 31 Is 13 � U 41 Q cy j U LO U = z cyl W •an - _ b ✓: C� f CD U O UN ttJ CQ v U L j 1. The owner or developer of a particular site should be responsible for, and should bear the cost of the evalua- tion of those hazards that can be evaluated on or in the near-vicinity of the site. Z. Those hazards that cannot be adequately evaluated at the site should be considered for evaluation with public funds. The nature of the funding may vary depending on the extent of the impact of the hazard. 3. To facilitate the administration of public safety, it may be desirable to undertake, with public funds, a general evaluation of site-related hazards as they exist within an entire jurisdiction. The application of these guidelines to geologic/seismic hazards depends on the type of hazard and the availability of in- formation that can be used to evaluate the hazard. For example, faults can be located on a particular site by the engineering geologist during the site investigation. However, the rock formations necessary for evaluation of the activity of the fault are normally present only at certain critical locations, and evaluation of activity may require a publicly funded investiga- tion. On the other hand, landslides can normally be evaluated as part of the site investigation funded by the owner or developer. Public agencies may wish to fund a general investigation of land- slide hazards to facilitate the administration of public safety, but the final evaluation must be a part of site evaluation because addi- tional hazard may be introduced by proposed modification of the site. The distribution of emphasis of this Seismic Safety Element is based on these concepts. Those aspects of a particular hazard that cannot be evaluated on a site-basis, or which can more effeciently be evaluated on a regional basis, are emphasized in this analysis. Those hazards that can be effectively evaluated as a part of site investigations are treated in a general way with the intent that the results be used to facilitate the administration I of public safety. It should be emphasized that such generalized evaluations should in no way be considered a substitute for a detailed site investigation which must consider not only existing conditions but also any hazards that may result from proposed modifications of the site. f A key step in hazard evaluation is public involvement, through their elected representatives, in the determination. of acceptable levels of risk. All hazards involve risk. A technical evaluation may determine certain risk parameters, but only the public can determine the acceptable balance between the risk of a hazard and the cost of mitigation. Because of the extreme importance of this step ,p, primary emphasis is placed on the tech- nical evaluation of available information relating to the risk of lseismic hazards. The technical analysis can provide such infor- mation, but only the public sector can make the final determina- tion of the acceptability of those risks. I The relationship between the concepts discussed above and the evaluation of specific seismic/geologic hazards is shown in i Table 2. The primary responsibility for evaluation of each aspect of a hazard is shown by an "XX", and by a "XXX" if a i determination of acceptable risk is involved. Those aspects for which either sector may commonly have a secondary responsi- bility are indicated by an "X". The intent is to show the distri- bution of responsibility for evaluation of a hazard; the overall regulatory responsibility of government is not included. 1 L _ I L I TABLE 2. DISTRIBUTION OF RESPONSIBILITY FOR EVALUATION OF SEISMIC/GEOLOGIC HAZARDS Responsible Sector Hazard Public Private 1. Fault rupture: a. Evaluation of fault XXX b. Location at site XX 2. Earthquake shaking: Ia. Sources of shaking XXX b. General levels of shaking XX X c, Effects on site XX 3. Tsunamic and seiche: a. Risk of occurrence XXX b. Effects on site XX 4, Dam failure: a. Risk of occurrence XXX b. Effects on site XX 5. Landslide: a. Regional evaluation XX X b. Effects on site XX 6. Liquefaction, settlement, &- subsidence: a. Regional evaluation XX(1) b. Effects on site XX X Secondaryresponsibility P Y XX Primary responsibility XXX Primary responsibility including determination of acceptable risk (1) Evaluation requires determination of expected shaking, II ANALYSIS OF SEISMIC HAZARDS ! A. GEOLOGIC AND SEISMIC SETTING Palm Desert is located in the Coachella Valley at the base of the San Jacinto Mountains. The City itself is located on Recent (Holocene) alluvium derived primarily from Dead Indian Creek (Figure 6). The alluvium is composed of unconsolidated boulder and cobble gravel and sand within and near the mouths of the canyons, grading to sand, silt and clay in the lower parts of the Valley. These materials range in thickness from a feather edge near the mountains to a 1000 feet or more in the Valey. The mountains west of the City rise abruptly from an elevation of approximately 200 feet on the Valley floor to 10, 831 feet at San Jacinto peak. The mountains to the immediate south and west of the City rise to elevations of 4000 feet near Haystack Mountain and 5141 feet at Sheep Mountain. They are- underlain by hard, resistant granitic and meta- morphic rocks that form moderately steep to steep ridges and canyons. Several large faults are present in the older granitic and meta- morphic rocks south and west of the City (Figure 6). Available Ievidence, however, indicates that none of these faults are active, and that the Banning and Mission Creek faults to the northeast and the San Jacinto fault to the southwest will be the principal sources of earthquake shaking in the area. 1 The seismicity of the Palm Desert area and its relationship to the seismicity of the Southern California region is shown on Figures 7, 8, and 9. Figure 7 shows the location of epicenters of earthquakes with a Richter magnitude of 4. 0 or greater. Figures 8 and 9 show only the larger earthquakes. It is readily apparent from these regional maps that Palm Desert is located in an area that is relatively "quiet" seismically. However, earthquakes, including those of magnitude 6. 0 and greater, are common to the north and northeast along the main branches of the San Andreas fault (Mission Creek and Banning faults), and to the south and southwest along the various branches of the San Jacinto fault. These faults, or branches thereof, are generally considered active, and are known to be capable of generating earthquakes of at least moderate magnitude (6. 0-7. 0) that could be damaging in the Palm Desert area. L + h l--'� 39 X + + x X 4 x < >1.;Y�xx x x }<Xd X \ x X Y.� I �{ kx' X �\ x x X X Y, X x X ,< x h X h X r.+ 3 + xx— 37 x X x X XX � x XX X x X x X x x x 1 xx \ �. x x xx X< 1X X W xX xx x + x' xX + X % 3r + X r XX X ,XX) x x X. ; X \ t x Wx y X x x >"Z. X X x �Ix X v p<, X ✓ x X X x xx+ x + 35 X X �°; x" ' '� Y. X xx x � ` X- X X X xX x X x x �` x XhX'<x xx X } x X xX xi xx x X x t xx; x x x hh v, X x X x x < >i lei x xX X, x x <.' X xx x \`\ �` X x x x X x t21 i 0 x (\�\ + \\`. + '3 x J \X x X �3t� xX\, J x x 7t 1 l _>E---X—_'-x�i<v X x < x � X X�Y. X .` 1 X X x \ X X xx x x X x + x X�<X Xy x X X S�< x \ + _9 ..X X x x,x- x x X �Y.Y'' > 2 X Xx X X yx X x X x EPiCENTEft S MACLS X X x �� x � ; x l I N < 5 x X ,<�x�c7< xx 4 5 N 6 X x x � 1 X ;< ><XX,,O< x>0OO< 119 117 x iiG x i15 ».�;xY. xx XXXXX x X '°` x xxx x Figure 7. Map showing location of earthquake epicenters, 4, 0 and greater, 1932-1972, Southern California region i_. I I + + M + + t Xx x� + + x x 37 in x I x x< ,ter x x 1 x x x x x x x XX 121 1 -0 X x 33 x t �, x X X XXx I EPTCEWER STMB3LS x x X. \ x x? \� x M < 4 x _ L_ ?GYXX 118 117 iiG i15 -. x X x X yx X Figure 8. Map showing location of earthquake epicenters, 5. 0 and greater, 1932-1972, Southern California region L_ r I + y 1 VV + + JV + + 37 f + '+' 1 XX X + X + 35 i x 121 1 Q + + 33 i + i 9 + f X + 32 iEPICENTER \ X C*� 6 { M < x \X 6xC 118 117 116 11S x X Figure 9. Map showing location of earthquake epicenters, 6. 0 and greater, 1932-197Z, Southern California region { B. FAULTING 1 , A ctive Faults ( The term "active fault" has been used by geologists and geophysicists for many years to describe faults which are known to be the source of earthquakes or which are known to have moved at the surface during historic time. As long as the use of this term was limited to the earth science professions where the limitations of the data are well understood, problems related. to a precise definition were minimal. However, the inclusion of the term in legislation at the State level has resulted in an effort by various State agencies and the several professional societies involved to clearly define "active fault". The definitions of "potentially active fault" by the State Geologist (Slosson, 1973) and "active fault" by the State Mining and Geology Board (1973), discussed in the Introduction, are of considerable help, but the practical aspects of definitive evalua- tion remain to be established. Also, these definitions relate to activity as determined by, and as applied to, the hazard of -fault rupture. Activity as may be suggested by earthquake epicenter !, locations is not defined, and the relationship between evaluations within the Special Studies Zones and the more general hazard of j earthquake shaking is as yet unclear. lWhile a high degree of conservatism may be feasible in the regulation of construction along active or potentially active faults, i, the use of the same criteria in establishing codes relating to hazards from earthquake shaking may have profound economic and social impacts. The activity of a fault is .related to recurrence rate which can be derived in at least three different ways: 1 . The analysis of the seismicity of a fault may reveal k relationships that indicate that, at least statistically, earthquakes of particular magnitudes recur at regular i rates. Data suitable for this type of analysis is avail- able for only about the last 40 years. Z. The measurement of the movement of the earth on either side of a fault, or crustal strain, can sometimes be derived from survey data. This information is available for a longer period of time, but movement is often so i_ small it is not detectable from ordinary data. Very accurate surveys have been conducted in recent years, but across only a few faults. If the rate of accumulation of strain is known, then the amount of time necessary to accumulate the strain necessary for an earthquake of a particular magnitude can be estimated from other relationships. 3. The relationship of unique rock units on either side of a fault may yield the geologic slip rate if the ages of the unique units are known. The principal problem with this method is the assumption that rates obtained for a time span of several million, or several tens of millions of years are valid today. The applicability of any of the above methods depends on the data available. Of the faults pertinent to this investigation, the ISan Andreas and San Jacinto are the best known, and data are available with which to utilize all three methods. Therefore, these faults will be considered first, and to some extent will serve as a icomparison in the analysis of the lesser known faults. 2. San Andreas Fault The San Andreas fault in the Palm Desert area is divided into f two major branches. The Banning fault is the closest, and is approxi- mately 2. 5 miles northeast of the nearest part of the City (Figure 6). The Mission Creek fault is approximately 2. 5 miles further to the I northeast, and is about 5 miles from the City at its nearest point. Neither fault, nor any known branches thereof, is considered suffi- ciently close to cause ground rupture within the City, but either could be significant sources of earthquake shaking in the City. While both faults are considered branches of the San Andreas fault, the evidence for Recent movement is considerably different. i Allen (1957) notes that: "There is little evidence of Recent strike- i slip movement (on the Banning fault) in the San Gorgonio Pass area, but earlier lateral movements are strongly suggested". The Mission Creek fault, on the other hand, "is marked by Recent scarps from Desert Hot Springs to its junction with the Banning fault near Biskra Palms". ' I A significant difference between the two branches is also apparent in physiographic features near Thousand Palms Oasis. Drainage patterns are offset approximately 3000 feet in a right lateral sense i_ i I along the Mission Creek fault. Pushwalla Creek can be considered a "classic" example of offset drainage due to Recent faulting. On the other hand, drainage patterns across the Banning fault in this area show no evidence of offset. Alluvial fans are generally symetrical around the canyons from which they are derived on the opposite side Iof the fault, and locally incised channels cross the fault without offset. This relationship is consistent with that noted by Allen (1957) for the Banning fault in that "the entrenched canyon of Whitewater River should be displaced if this type of Recent movement (lateral offset) had been large'.'. IThe relationships discussed above and the general distribution of seismicity discussed previously strongly suggest that while the Banning branch of the San Andreas was active during Quaternary time (last 2, 000, 000 to 3, 000, 000 years), it is the Mission Creek branch that has been actively moving during Recent time (last 10, 000 to 11, 000 years). Of the two branches the Mission Creek fault in the most likely source of strong shaking at Palm Desert. 3. San Jacinto Fault I The San Jacinto fault extends from Cajon Pass to Mexico as a series of en echelon or branching segments of a relatively continuous fault zone. Geomorphic features indicating Recent movement have been mapped along various segments (Sharp, 1972), and numerous epicenters of earthquakes in the magnitude 6+ range have been located along the fault. The most recent of these, the Borrego Mountain earthquake of April 9, 1968, has been studied in great detail (U. S. Geological Survey, 1972). Ck 4, Recurrenf Intervals for the San Andreas and San Jacinto Faults 1 _ Data available from previous studies (Envicom, 1974) bearing on the recurrence of earthquakes on the San Andreas and San Jacinto faults can be summarized as follows: i i I San Andreas Fault San Jacinto Fault Seismcity (Point recurrence 526 years 200 years interval for magnitude 6. 5 earthquake) Crustal Strain rate 0. 20 ft/yr 0. 08 ft/yr i Theoretical recurrence rate (6 cm/yr) (2. 4 cm/yr) for magnitude 6. 5* 10 years 25 years Recent or Quaternary movement 0. 08 ft/yr 0. 008 ft/yr Theoretical recurrence rate (2. 4 cm/yr) (0. 25 cm/yr) for magnitude 6. 5* 25 years 240 years 'eAssumes 60 cm displacement for magnitude 6. 5 earthquake. Of the above rates, seismicity and crustal strain are related in that they are derived from the relatively short sample interval of 40 years or less. Recent movement, on the other hand, is based on time periods on the order of 10, 000 to 302 000 years. The large difference in the recurrence intervals for the San Andreas fault can be explained if it is assumed that approximately 90% of the accumulating strain is being stored for larger earthquakes, and that the observed seismicity represents only about 10%of the strain. Assuming an upper limit of magnitude 7. 5 for these "larger earthquakes" (Greensfelder, 1973) and a fault slip of 3 meters i (Bonilla and Buchanan, 1970) accompanying such an earthquake, ( the recurrence intervals for 90 fo of the two strain or movement rates are as follows: Recurrence Interval i Source Rate 90% of Rate for Magnitude 7. 5 Crustal strain 6 cm/yr 5. 4 cm/yr 55 years Recent movement 2. 4 cm/yr 2. 2 cm/yr 136 years L_ I i f I _ Recurrence rates for the San Jacinto fault are more consistent_ This fault has a well established history of being the source of earth- quakes in the range of magnitude 6. 0-7. 0 at relatively frequent intervals. The recurrence interval of 200 years for a magnitude 6. 5 event is considered reliable. The crustal strain value is based on a relatively short period of measurement. It is corroborated in part by the offsets of entrenched streams, but the historic record f is so consistent, it is deemed the more appropriate. The most probable earthquake is considered the magnitude 6. 5 event, but the jmaximum probable of 7. 5 (Greensfelder, 1973) is considered possible. fThe indicated recurrence interval for such an event, however, is approximately 700 years. I 1 5. Concealed Faults on the Southwest Side of the Coachella Valley Several lines of evidence are noted by Sharp (1972B) as indicating the presence of a fault or faults burried under the alluvium on the southwest side of the Coachella Valley. First, the large difference in elevation between the San Jacinto and Santa Rosa Mountains and the steepness of the slopes suggest uplift along a fault. Second, there is j a pronounced gravity gradient along the line of the proposed fault and third, structure of the exposed rocks suggests that downfolding fcannot account for the gravity gradient. The precise location of the fault is not known, and its location on Plate I is based primarily on i the gravity anomaly. However, the lack of surface expression that precludes a more precise location also indicates that this fault "has been inactive for a relatively long period" (Sharp 1972B). i l I - I_ 6. ( Potential for Sympathetic Movement Relatively small movements are also known to occur along faults - as the result of the shaking generated by movements on other faults. The San Andreas, for example, moved approximately 1. 5 cm at Red Canyon southeast of Indio in response to the shaking generated by the Borrego Mountain earthquake on the San Jacinto fault (Allen et al. , 1972). Known occurrences have generally been limited to active or potentially active faults except in areas of very strong ground shaking. While this possibility cannot be completely discounted, it is not con- sidered a significant hazard on faults in Palm Springs. I 7. Summary of Faulting Major faults located within the City limits of Palm Desert include the faults in those in the granitic and metamorphic rocks in the western and southern part of the City, and the South Pass fault group in the northern part of the City. These faults were probably active during the early Quaternary uplift of the San Jacinto mountains, but there is no evidence to indicate that they are active today. Geologic hazard zones have been established by the State Ceologist as required by the Alquist-Priolo Act (SB 520) along the San Jacinto fault to the southwest and along the several branches of the San Andreas fault (Garnet Hill,- Banning, and Mission Creek) to the northeast. No such zones have been established within the cityllimits of Palm Desert, and none are anticipated on the basis of existing information. ( Information bearing on the recurrence of earthquakes on the San Jacinto and San Andreas faults has been developed in the preceeding sections. This information is pertinent to Palm Desert in that it bears on the risk of earthquake shaking in the City. While the results of analysis using various` types of data are somewhat inconsistent, the following are considered the most important to the risk of earth- quake shaking at Palm Desert 1. The San Jacinto fault is one of, if not the, most active faults in California. It has a well established pattern as the source of numerous moderate sized earthquakes in the range of magnitude 6 to 7 about once every 12 years at some point along the fault and about every 200 years at any given point. Recent activity has centered primarily on the southern segments of the fault, but activity should increase on the northern segments nearer Palm Desert in I the near future. 2. While an earthquake of magnitude 6. 5 is considered the most probable event on the San Jacinto fault, a larger event of y about magnitude 7. 5 should be considered as a possibility, _ particularly in the design of the more important or critical structures. 3. The San Andreas in the Palm Desert area exhibits a relatively low level of seismicity. The recurrence interval for a magnitude 6. 5 earthquake resulting from slip along any particular part of �- the fault is approximately 500 years. I L_ I 4. Crustal strain (regional less San Jacinto movement) and Recent and late Pleistocene movement, however, suggest a much higher level of activity. If these indicated rates of movement are converted to a theoretical recurrence interval for a i magnitude 6. 5 earthquake, it is only 25 years or less or one- tenth or less that from seismicity. 5. Data on movement of the San Andreas fault system along its entire length indicates rates of movement in the range of 5 to 8 cm/yr are likely. Only about one-third of this can be accounted for along the San Jacinto fault, leaving the San Andreas itself about twice as active as the San Jacinto. I6. The San Andreas fault in the Palm Desert I area is generally considered to be part of an "active area" rather than one of the "locked segments" of the fault. A "great" earthquake (magnitude 7. 8 or more) is, therefore, considered unlikely. A "major" earthquake, however, with a magnitude of approxi- mately 7. 5, is considered likely. 1 7. Recurrence data is somewhat conflicting, but "best estimates" for expected earthquakes are as follows: Fault and Earthquake Magnitude Recurrence Interval San Jacinto fault Magnitude 6. 5 200 years Magnitude 7. 5 500 years San Andreas fault Magnitude 7. 5 50-150 years i C. EARTHQUAKE SHAKING 1. Sources of Expected Shaking The main sources of earthquake shaking at Palm Desert : are the San Andreas fault on the northeast and the San Jacinto fault on the southwest. Information bearing on the risk of occurrence of earth- quakes of various magnitudes on these faults has been developed in the preceeding section. The following are recommended for consi- deration as the earthquakes that should be taken into account for various types of facilities is as follows: Magnitude of Earthquake 1 Use San Andreas Fault San Jacinto Fault JCritical Facilities 7. 5 7. 5 Normal Commercial Facilities 7. 0 6. 5 i Normal Residential Facilities 6. 5 6. 5 The engineering characteristics of these earthquakes are developed in the following sections of this report. 2. Intensity of Recorded Earthquakes i The intensity of shaking during past earthquakes is pertinent to the problem of predicting the expected shaking during future earthquakes because: 1) it can serve as a rough check on the more quantitative methodology to be used to develop data useful to engineers; and, 2) variations in shaking experienced at locations on different types of materials can be a rough check on the relative differences in shaking expected in the various microzones. Some information is available on shaking intensities in nearby Palm Springs, but detailed data, suffi- cient to be of use in checking the microzonation, is not available for Palm Desert. The earliest earthquake in the area for which information is available was the May 1868 Dos Palmas earthquake centered near the northeast end of the Salton Sea. Based on a report of Holden, Wood (Wood and Heck, 1966) estimates the maximum intensity at Mexcalli IX or perhaps X. Proctor (Lamar, Merifield and Proctor, 1973) shows the length of rupture as approximately 30 miles along the i northeast shore of the Salton Sea. Based on this length of rupture, the Richter magnitude would have been approximately 7. i The closest earthquake to Palm Desert which was of significant magnitude and for which any detailed data is available is the Desert Hot Springs earthquake of December 4, 1948. The maximum intensity of VII was felt from Cabazan, Morongo Valley, and Twentynine Palms on the north to Indio on the south. Reports (Murphy and Ulrich, 1951) indicating Mercalli intensity of VII at nearby Palm Springs are as follows: I I "Palm Springs — Center Building, a two-story ultra-modern building of steel and concrete with large patios. Two 9 by 12- foot plate glass windows broken, many plaster cracks both inside and outside, cracks seemingly followed steel in concrete. ID Rexall drugstore — One-story building. Large plaster crack in concrete block front, crack showing inside only about 8 feet above ground level. Glass not broken. Plaza theater — Rustic finish with open ceiling of 10 by 12- inch bolted beams, block walls. No damage to structure. Loose colored glass plates in bottoms of several chandeliers fell out injuring patronx. About 50 children in theater left hurriedly. Hotel del Tahquitz — Rather old two-story adobe structure reinforced by addition of a number of columns and beams duplicating the original design. Building has gone through several. local earthquakes. Although a number of cracks developed and f old ones were further widened, there appeared to be no structural damage. Bullocks — Modern two-story steel, concrete, and plaster structure. Outside damage was to plate glass windows were 4 panes 6 by 6 feet were shattered. Larger panes were riot. Interior shows many small plaster cracks especially where one building material joined another as at baseboard and at-partitions butting up against a wall. On the second floor 6 fluorescent hanging fixtures with decorative glass bottoms and slides broke or dropped their glass. No apparent structural damage. Carnell property — Solid concrete two-story structure with tile roof. Small cracks showed in walls and a number of times were loosened, quite a few dropping to street both to south and west. Small antique shop at rear of this building (one-story concrete block about 18-foot square with tile roof) lost its chimney. A number of objects fell from shelves in all directions- Francis Stephens School — A rambling one-story grammar school. Minor stucco cracks. " Recent earthquakes of intensity (Modified Mercalli Scale) V or greater at nearby Palm Springs are summarized in Table 3. The Desert j Hot Springs earthquake discussed above caused the highest intensity I of shaking. Data from this earthquake is pertinent to the shaking analysis; the remaining earthquakes are included primarily for informational purposes. TABLE 3. (SUMMARY OF RECENT EARTHQUAKES OF INTENSITY (MODIFIED MERCALLI SCALE) V OR GREATER AT PALM SPRINGS Distance to Richter Maximum Intensity at Epicenter Date Magnitude Intensity Palm Springs (Miles) March 25, 1937 6. 0 VII VI 33 May 18, 1940 6. 5-7. 1* X V 125 October 21, 1942 6. 5 VII V 87 August 15, 1945 5. 7 VI V 62 December 4, 1948 6. 5 VII VII 12 March 19, 1954 6. 2 VI VI 56 i April 9, 1968 6. 5 VII VI-V 73 1 *The 1940 Imperial Valley earthquake, originally assigned a magnitude j of 7. 1, has recently been dhanged to 6. 5. 3. Engineering Characteristics of Expected Earthquakes (- a. Methodology r The derivation of the engineering characteristics of a particular earthquake at a particular site is normally a two-step process. These steps are the two considerations that have been discussed in idescribing the changes in earthquake.intensity; that is, distance to the source of the earthquake and local conditions. Where the distance factor is treated as the travel path in deep bedrock, the effect of local conditions is the near-surface amplification of the waves as they travel upward through layered rocks. The mathematics and geometry of this calculation are shown in Figure 10. 1 The distance problem is a relatively simple part of the calculation. However, near-surface amplification and the choice of type earthquakes are more complex problems to be discussed in detail in the next two sections. 8 � Site 4, A) •t Poch I The spectrums SVI T Of the earthquake, E7 recorded at site 19 at- distance dy from the source of the earthquake is: SV1 = E Al di where A is the hear—surface lificaticn of the bedrock ,imntion► l dampirt;� in bedrock is neA l iE!ib l e9 and spreading is cylindrical . Likewise7 the spectrum at site 2 is: SV2 = E A 2 d2 Therefore: SV2 = SVI dl A �" d2 A2 Where SVi , SV2t A, , and A2 are comps ex furZctians of frequency. Figure 10. IGeometry and mathematics of computation of the engineering characteristics of an earthquake. i b. Near-Surface Amplification 1) Physical Principles The amplification of earthquake waves traveling through a media of differing physical characteristics (i. e. layered rocks) is based on two physical principles: conservation of energy, and the selective amplification of resonant frequencies. The principle of conservation of energy applies to the transforma- tion of the physical properties of a wave as it travels from the very fast, dense rocks at depth to the much slower, less dense rocks or soils at the surface. In this conversion, the energy of wave velocity is converted to energy of wave amplitude. The mathematical expression for this change as a wave travels from layer 1 to layer 2 is: 1 AR D2V2 = D1 V1 where: AR = amplification ratio (layer 2 to layer 1), D1 = density of layer 1, D2 = density of layer 2, V1 = velocity of layer 1, and t V2 = velocity of layer 2. The above equation involves both velocity and density, but velocity is by far the most important. 1n the overall change from granite at depth to an average soil at the surface, the density will typically change from 2. 7 to about 1. 5; a ratio of less than 2:1. Velocity (shear-wave) on the other hand will typically change from about 11, 000 ft/sec to less than 500 ft/sec; a ratio of more than 20:1, and 10 times the density change. The selective amplification of resonant frequencies is more I complex, but in simple terms, the rock layers act somewhat like a series of organ pipes that amplify waves of particular frequencies. The frequencies that are amplified are those that form a one-quater- wavelength standing wave in the layer, and all higher modes. The dominant periods of a layer are thus: 4 H 4 H 4 H T 1 V' 3 V' 5 V etc. where: T = dominant period, H = layer thickness, and V = layer velocity (shear wave). For most sites, with many layers of varying thickness and a gradual increase of velocity with depth, selective amplification is secondary in importance to the more general amplification due to decreasing velocity and density. However, where there is a very pronounced velocity change at relatively shallow depth, as in the Mexico City area discussed in the Introduction, the con- centration of energy in a narrow frequency range can be very important for structures having a similar natural period of vibration. In addition to the two principles considered above, damping can be important for sites with thick layered sequences. Waves traveling in fast, dense rocks such as granite are almost un- affected by damping, but unconsolidated materials such as soils, soft sands and shales can effectively damp earthquake waves if they are present in sufficient thickness. Overall, the effect is to cancel a part of the wave amplification of the slow, less dense rocks, because rocks with high amplification characteristics generally have high damping factors. For damping to be effec- tive, however, thick layers are required. Thus, lowvelocity materials may be "good" or "bad". If, they are present as a relatively thin layer (15-100 feet), amplification may be very significant. However, if they are present as very thick layers (several thousands of feet), damping can be effective in reducing the amplification normally expected at sites underlain by low velocity rocks. From the discussion above it is apparent that the most important physical characteristic of a site is the velocity or velocities of the layers underlying the site. Density is less important, and it can be estimated from velocity if the rock types are known. Damping is important for thick sections, and it too is closely related to velocity. Thus, if the velocity of the wave type of interest is known, the density and damping can generally be estimated to an acceptable degree of accuracy. �I Earthquake shaking is the result of complex combinations of several types of vibrational waves. The primary components of earthquake waves are the so-called body waves that travel through the deeper parts of the earth's crust. Body waves include Un __`__— —`t"`"o—\ rlission Cre�K -t u�T 1a Ft f ti a 1 e j II n r� cp I c t 1 + •!_1•-- o o10 � .. O'q 10 10 r• a kd 4 p LA pia l•' 1� OnLA I � f m � I (.n - - _ 5,an Jac.1ni"o i n primary P wave r compressional waves and the secondary the z i o com re P Y ( ) y (S-wave) or shear waves. For waves traveling at depth, and i refracted upward to the site (Figure 11), ;the P-waves, vibrating parallel to the propagation direction, dominate the vertical com- ponent of shaking. The S-waves arrive later and vibrate normal to the direction of propagation; they make up the major part of the damage-inducing, horizontal components of shaking. Thus, 1 it is the shear waves that are of primary importance in the analysis of earthquake shaking. 2) Model Analysis The analysis of near-surface amplification at Palm Desert is based on five computer-generated models shown in Figures 12 i through 16. 1 Velocity data is not available for specific locations in Palm Desert, but the rocks and soils are similar to those in other ; parts of Southern California for which good data is available (Duke and Leeds, 1962 and Duke et al, 1971). Shear-wave, density, and damping for materials at Palm Desert ! were estimated from these sources, and layered models were developed for various thicknesses of alluvium over hard bedrock. The amplification spectra were computed and plotted by Mr. J. A. Johnson using the latest computer programs developed at the Earthquake Engineering Research Institute at UCLA. The application of these spectra will be discussed further under Microzonatibn.. C. Type Earthquakes Earthquakes to be considered in the analysis of expected ground shaking include magnitudes 7. 5, 7. 0, and 6. 5 on either the San Andreas or San Jacinto faults. The strong motion of the 1940 Imperial Valley earthquake of magnitude 6. 5 was recorded at a distance of about 5 miles, and is a good, local example of a magnitude 6. 5 earthquake. The response spectrum of one component of this record, and smoothed envelopes of the response curves for both horizontal components for 0, 5, and 10% of critical damping are shown on Figure 17. It is considered conservative for this magnitude because rupture along the fault plane extended to the surface, and because the duration of shaking was longer than most 6. 5-magnitude events. The strong motion for the magnitude 7. 5 event is taken from the 1952 Kern County earthquake (magnitude 7. 7) as recorded at Taft. The distance is larger than desired (28 miles from fault to recording site), but very few records are available for earthquakes of this magnitude. The response spectrum of one component of this record, I i I i L^. ( i I � i t I L � 9 1 I t 1 i . S I 111 � j I - I `E9 T vD 1 Figure 12. Amplification spectrum for bedrock site condition with 25 feet of weathered material over hard rock i �I E{ !E { 16 1 { ` I t � t t - � L-• i.r3 ' ! i ri i I ! Figure 13. (Amplification spectrum for 60 feet of alluvium over hard bedrock i i - t i i I 12 I in t l 2.511 =,r Gii Lhl r Figure 14. 'Amplification spectrum for 200 feet of alluvium over hard bedrock i I , 1 - 1 1 1 I_- - +.-1 j! I 01 "It I L , I f + 1 t i iJ. ID 1 . 20 1 _ 51D T \.. D Figure 15. Amplification spectrum for 500 feet of alluvium over hard bedrock i f i I I CD _' )'Z2 I t;_ -? { 81 31 I 1 Of FER1010 Figure 16. Amplification spectrum for 1000 feet of alluvium over hard bedrock I IMPERIAL VALLEY EARTIHOURKE MAY 18 , 1911-0 - 2037 PST III0001 0,001 .0 EL CENTRO SITE 1MPERISL VHLLEY JRRJGflTIDN DISTRICT CCXP 300t' DRNPING YRLLES RRE 0. 2, 5. 10 RNr 20 PERCENT Or c91flcRL 400 I ` 400 1 I 200 ��d�p 9c ( I - 6'.-O- 2U0 p0 Cl jP t `oce Y°O �r• I .SQ 100 - IOU 80 �9 — I — �i 71 80 O 1 40 1 70. 4U Js A O 20 20 c.) a� 8 ' 1 1 _ 4 8 I ~ 6 I �� `I o�p 6 O 4 J �� 02 W > 2 .O °'p° 2 •o � ° o`er \, •OF p0 I / f' •02 / � � Op`i' � I .8 I O� O —8 •O— O .6 4 , Opp 4 .2 I I 1 1 1 I � I j .04 .06 .03 .1 .2 4 111 6 .8 1 2 4' r '6 8 10 20 PERIOD (secs) Figure 17. !Response spectra of one component of the El Centro record of the 1940 Imperial Valley earthquake. The dashed curves are smoothed envelopes of the two horizontal components for 0, 5, and 10 jo critical ' damping f and smoothed envelopes of the response curves for both horizontal components for 0, 5, and 10% of critical damping are shown on Figure 18. Analysis for the magnitude 7. 0 event is based on a logarithmic average of the results for the 7. 5 and 6. 5 events. d. Microzonation 1 Methodology The spectrum of the ground motion at a site within the City can be computed using the following equation (see also Figure 30): dl A2 SV2 SV1 d2 Al I where: SV2 = velocity spectrum at the site, SV1 = velocity spectrum of the "type earthquake", di = distance, in bedrock, of the "type earthquake" record from the earthquake source, d2 = distance, in bedrock, of the site from the earth- quake source, (- A1 = amplification spectrum of site of the "type J earthquake" record, and A2 = amplification spectrum of the site. In the equation above, the distance factors are simplified from a - more complex equation assuming cylindrical spreading from a line source and negligible damping in bedrock (granite or meta- morphic rocks). The spectral relationships are based on linear system theory (Duke et al, 1970) valid for the Fourier spectra of the ground motion. Their application to the response spectra of the ground motion at values of 0-10% of critical damping is an approximation considered adequate for the generalization necessary in zoning an area the size of Palm Desert. ' - The mathematical expression above is composed of two basic parts: 1) a ratio expressing the effect of differences in distance from the source of the earthquake; and, 2) a ratio expressing the effect of differing site conditions. These two parts of the formula. are also the two basic steps of the zonation process. IV L KERN COUNTY , CALIFORNIA EABTHOUAKE JULY 21 , 1952 — 011-53 PDT IIIR004 52.002.0 TRFT LINCOLN SCHOOL TUNNEL C0M.- S 6 9 E i DAMPING ULUES ARE 0> 2, 5, 10 RNO 20 PERCENT OF CRITICRL 400 OKI 4C0 � 200 KO ��' G-o°° 200 p cc� 00 900 o�• �yQ 100 20—�0� O 110 I 100 1 -�=9 \ $o % so 0 60 \0 \ I ( (600° — 60 40 n,o 20 f ((( \ a l OFF" _ I 4 r �-• 20 10 lo } s �� — I , `� a y I O 4 u 4 / < J W o� ; . 2 ► -O�, opp� 2 I r .. .iT 06` .Op R� •Op ,pp� l r 0i O O r °0 I, ' -4 'off - � .4 .2 1 .04 .06 .08 .1 .2 .4 _6 .8 1 2 4 6 8 10 20 PERIOD (secs) Figure 18. (Response spectra of one component of the Taft record of the 1952 Kern County earthquake. The dashed curves are smoothed envelopes of the two horizontal components for 0, 5, and 10% critical damping. 2) Zone Boundaries Based on Distance The effect of distance is a simple inverse proportionality relationship. That is, for each doubling of distance, the spectral velocities decrease by a factor of two. Two aspects of this rela- tionaship are important to the choice of zone boundaries. First, if a near-constant difference in the range of shaking properties ( across the zones is desired, then the zones will be narrow near the source of the earthquake, and double in width away from the source. Second, the variation due to distance is gradational, and the choice of the particular distances from the fault that is the source of the earthquake is arbitrary. The distance zonation at Palm Desert is based on the following considerations. ( 1. The consideration of two faults as the sources of the expected earthquakes is simplified if the distance zones are symetrical about a line half way between the faults. This medial line, half way between the nearest branch of the San Jacinto fault and the Mission Creek branch of the San Andreas fault, bisects Zone III. 2. Arbitrary divisions of otherwise relatively continuous parts of the City should be avoided if possible. 3. The zones should be broad enough to reflect the assumptions and generalization of the analysis that are the result of a j limited amount of basic data. However, they should not be so broad that the resulting shaking criteria would not Ibe resonably applicable to all parts of the zone. 3) Zone Boundaries Based on Site Conditions Site conditions at Palm Desert can be divided into two basic types: bedrock of metamorphic or granitic rocks, and alluvial areas. The response of the bedrock will vary somewhat depending on the degree of and thickness of weathering, but this will be minor in comparison to the large differences between bedrock and alluvial sites. The response of the alluvium was investigated using the near- surface amplification models discussed previously. Models were computed for 0, 60, 200, 500, and 1000 feet of alluvium over bedrock , (Figures 12 through 36), with the results varying in a logical and regular manner. The thin alluvium is characterized by a strong '1 amplification in the low-period (high frequency) range. Increasing the thickness of alluvium decreases the amount of amplification but also "spreads it out'' over an increasingly high range of periods (lower frequencies). The variations in amplificatiorl between thicknesses of alluvium of about 200 to 1000 feet are considered as within a range that can reasonably be lumped within one zone. At thicknesses of less than 200 feet the condition known as the "edge effect" becomes pronounced, and the amplification approximately doubles in the range of periods that is most significant for the low-rise construction (less than 5 stories) present at Palm Desert. The models can be generalized as follows: Short-Period Transition Long-Period Thickness of Amplification Period Amplification Alluvium (feet) Factor (Seconds) Factor 0 3 0. 1 2 0 (with 9 0. 1 2 25' weathered.layer) 60 16 0. 3 2 I 200 12 0. 5 2, 5 500 10 1. 0 3. 0 1000 8 1 . 8 3. 0 From the above, three zones based on site conditions are defined with amplification characteristics as follows: Short-Period Transition Long-Period Zone Designation Amplification Period Amplification and Characteristic Factor (Seconds) Factor C Bedrock (firm to 3 0. 1 2 hard) B Alluvium, 200' or 15 0. 1-0. 5 2 less A Alluvium, more 10 1. 0 j 3 than 200' i In addition to the basic rock and soil types discussed above, there is an older and firmer alluvial unit in the Cahuilla Hills area. Its characteristics are such as to reduce the near-surface amplification particularly where the unit is thin as it is near Cahuilla Hills. Specific velocity data are not available, but the general physical characteristics of this unit indicate that the near-surface amplification should be reduced by about one-third. Since this coincides approximately with the ampli- fication levels for the "A" zone, the "B" zone (area of thin alluvium) has been deleted in the area of the older alluvium. I 1 i _ i i I 200 F, I All Wok XV 50 cr o 0 ; GG Ln 2 CL v 0 V •� O I 10 0 a� �✓ l 5 r 2 . ` "\4 ., .05 0.1 0.2 0.3 0.5 1.0 2:0 3.0 Period (sec.) Figure 19. 'IResponse spectra, type 1 I 200 100 1 ' ix f A I cZ � 1 - i ..- ACC \ (no 50 2 W _ . C CL c 20 o U > 10 — a 1 I I I j YX 2 I 1 05 0.1 0.2 0,3 0.5 .1.0 2.0 3.0 Period (sec.) Figure 21. Response spectra, type 3 `<4 200'r< K ></\< J Ifl0 h t ` fir G cn �O O 20 0 U / O /. 3 'f � 10 I V Y ! I / - t i r � \ 5 2 �! I I .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) l Figure 22. Response spectra, type 4 I I � � 1 200 100 �� ► ► j � ,, ► �. G CL 20 Ov >, 0 U O > >14 / � 10 c i AN 5 d ► f I 2 1 .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) Figure 23. Response spectra, type 5 I !� 200 � n `� 1 �. I '`� A� c)� I A' � I I I X or. 50 2 U �d I �!� a,o .�� I o• N a \ S 20 � O ! U ' O � v i > W 10 I ! �! V 5 i 2 .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 j Period (sec.) Figure 24. Response spectra, type 6 l i 200 < x 100 tiS ,9c 50 4�. L Cl 20 �\ � O 0 Cv 10 / i v a i 5 N,l_ \ 2 i .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) i Figure 26. Response spectra, type 8 i t /x 200 W O. /o .� 50 O� f M1 U U lv CL i c. 20 O a O I U U � 10 > \ ►= 7Zu- 1 t I 5 2 .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) Figure 27. Response spectra, type 9 i t v 200 \ / 1�v AA �j 50 Qr GQ `� U n v 20 f U D� o AV > 10' 1 D � 2 r F `) ► .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) Figure 28. Response spectra, type 10 1 i f � I I I 200 t I" 100 50 .- GG UCn �d � � 2 C I a. 20 `` q 41 U � O O O ,Q , V 5 L 2 V i .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) Figure 29. Response spectra, type 11 i 200� N < >< KX Iflo , 50 />G L O n 20 I zi v 0� �f i O N > 10 ✓ i i - a 5 �- 2 i \< .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 i Period (ssc.) Figure 30. Response spectra, type 12 i „ N A \nA 200 100 � Ix IXV 50 J OL 120 I O I4 U iO 10. I I O I i I I 5 L 2 r I + 1 I .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 i Period (sec.) Figure 31. Response spectra, type 13 s 200 100 50X�Z a) 20 CL Z o v NJ (0 a� 17 5 XZ 1 i 2 I .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) i Figure 20. Response spectra, type 2 i 200 l l oo rQr. i CL - L v 20 0' V > O� Q� 10 � n) 0 a> i 5 le IVV / > 2 I , .05 0.1 0.2 0.3 0.5 I.0 2.0 3.0 Period (sec.) Figure 32. Response spectra, type 14 L A A 200 ' I 100 1 1 I �co i i Q,. Q /J IU dG Q` I N O c 20 .� I U O cll 10 a � v I 5 ` i I, . 2 J .05 0.1 0.2 03 0.5 1.0 2.0 3.0 Period (sec.) l Figure 33. Response spectra, type 15 i i 200 w<< l 100 I 2' I 50 Qj r U �d N QJ ICl 20 �\ .- D� U i O 10 ' v ( a -�, a� _ CC � 5 � 2 I I A .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) Figure 34. Response spectra, type 16 L i 200 \ /<><I ><x lO0 ' I \i i oy. 50 i �z \>< ! U \a 2 Cn u � O a - c 20 �\ O_ 10 a) i 5 I � i 2 l .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) Figure 35. Response spectra, type 17 j I i R 200 �a�l I � ~Qi 50 a 20 o� > > 10 i I 5 K�l Ni&W/ 2N AI 1 I 3 .05 0.1 0.2 0.3 0.5 1.0 2.0 3.0 Period (sec.) Figure 36. Response spectra, type 18 f i t 4) Shaking Characteristics for Zones i I The 4 distance zones and the 3 zones based on site characteristics combine for a total of 12 possible microzones. However, the thick alluvial zone is not present in Zone IV, and 11 microzones, based on both distance and site conditions are present. The zones are designated using a combination of Roman numerals for distance and letters for site type. Their areal distribution is shown on Plate I. The generalized characteristics (maximum ground acceleration, predominant period, and duration of "strong" shaking) of expected ground shaking are shown in Table 4 for each category of use in each of the eleven microzones. Response spectra have been derived ( for each of the three earthquakes (magnitudes 6. 5, 7. 0 and 7. 5) in I the "A" and "C" zones. These are included on Figures 19 through 36, and are also referenced as to zone and use category in Table 4. Spectral values for the "B" zones can be obtained as indicated at the bottom of Table 4. 4. Comparison of Predicted and Observed Shaking I The highest intensity of ground shaking reported in the Palm Desert area is the Mercalli VII experienced during the 1948 Desert Hot Springs earthquake of magnitude 6. 5. While the relationship between ground acceleration and intensity is rather general, the range of acceleration that generally corresponds to an intensity of VII is about 0. 1 -0. 1 5g. This is somewhat less than the 0. 22g predicted for an alluvial site in downtown Palm Desert during a magnitude 6. 5 earthquake on the San Andreas fault (Table 4). The most probable explanation is that the "type earthquake" used to derive the 0. 22g involved the rupture of the fault at the surface, while the Desert Hot Springs earthquake did not involve surface rupture. The accelerations from the latter would be expected to be lover for the same distances from the epi- center or surface trace of the fault. The predicted shaking charac- teristics for the magnitude 6. 5 earthquake are therefore somewhat conservative in comparison to the 1948 event. D. SECONDARY HAZARDS 1. Settlement Settlement may occur in poorly consolidated soils during earth- quake shaking as the result of a more efficient rearrangement of the individual grains. Settlement of sufficient magnitude to cause significant structural damage is normally associated with rapidly deposited alluvial soils, or improperly founded or poorly compacted i_ 4 Co �O Ln 41 U] 1 o O Ln CD CD Ln CD Ln Ln W U N rI N N f N u () N N "� N t I t I [.� '`'' Ln Ln O LA Ln Oi Ln L.n Cl o H -4 � 0 Cy bZocn 4N o x U Cd O F 1 M M 1-�-1 E I O cd O O O O O O O O O O P, U) CA � `F-I L, 1 1 I 1 1 1 1 1 1 1 Q) O Q' a) N N C N N M N N M N N M rl M -4 0 , o 0 0 0 0 o u co U rn W U Ln N 00 N M Ill �o Ln! o y E I O M Ln CD MC -+ N CDO jbZ N W O O O O O O O O O Oj w a O oo 0- 1 O N Ln O U fd O O Lfl O O Ln O O Ln Lfl w U U] fWf_d� r` U] M M N M M N M M N i 1 U � i I 1 i I I 1 1 I 1 fd ,� H Fi 'd �'+ Ln Ln o LA Ln o Ln Lf) O O E 1 4 fd O � N N N N N N N N N j UJ . 1 J ,+,I Lr) ,� -0 O j H cd U f1 w j o an fd D `�' �r .o d+ .D Ln Ln Ln rd Q ° w (d N IV O rl CJ . , to 4r' 0 o O o o O o 0 0 o fd o O-, cd rd U G' d �+ I I 1 I 1 I 1 I 1 I U 41 Q o F � U M M M M M M M M M M U ,Q '1 u ti o 0 0 0 0 0 0 0 o a � ° r�rrra� Cd :j fd W 0 Id O -0 w � Ln 00 00 M O M -J G, O Ln U O M Ln --IN M .-a O 0 OU U U Q Z 0 O O O O O O O O O O c3 N Ln 0 u41 +'' O O O O O O O O O O w � C� j z ,U cn d d' cn d' d' M M N cd _ Lh W 1 ti CD O O O j 0 CD CD O CDCDN U) O w J +' 0M M N M M N M M N N U o _ O O `-1 U U�0 O In f d O bi �, P t4 ( rl 4 N � -t' d' �t1 -,t -t1 -,I, ct' d' -t1 -d O +U w 43 x d r, fo U W 0 4d o 0 0 0 0 0 0 0 0 o a U) w cz i r-fU � N N N N N N N N N N >+ - Exa) O O o o O o o O o o o o E I U fn r} g '-4 ul N Ln N rn Ln N -14 I` Ln N r -,H } o 0 F i k �. Ln co N d N M Lf) --Ibn N I d fd U U U O O O O O O O O O O td U U P I Q R; U �L � li a II n u H H H F-i F-i ~{ H I I L fills. The former are generally limited to active stream channels in which the risk of flooding is far greater than settlement. The problem of poorly compacted or improperly founded fills is only indirectly related to seismic hazards in that strong ground-shaking may "trigger" an already existing instability. Such instabilities are just as likely, and often are more likely, to be "triggered" by other events such as heavy rainfall. The proper solution to such problems is to require that fills be placed under the supervision of a soils engineer, and, where hillside terrain is involved, also under the supervision of an engineering geologist. In so doing, the engineer and geologist should take into account forces resulting from ground- shaking as specified herein or as developed from more detailed studies of site conditions. Soils in the Palm Desert area consist of the alluvium under- lying the City and thinner residual and locally derived soils in the mountainous areas. The alluvial soils are granular to coarsely granular. The upper few feet is often loose and poorly compacted, and may require some removal and recompaction for heavy structures. Differential settlement, however, should not be a problem provided normal soils engineering precautions are taken. The soils in the mountainous area of the City are primarily residual (derived in place) soils with some locally derived alluvium. They are relatively thin, and should not be a problem with respect to differential settlement. Regional settlement may occur as the result of groundwater withdrawal and the lowering of the ,water table. Such settlement is not normally a hazard to structures because it does not result in differential movement that would cause damage. Aqueducts or other structures that require a precise maintenance of grade may be affected, but most are not. 2. Liquefaction Liquefaction involves a sudden loss in strength of a saturated, j cohesionless soil (predominantly sand) which is caused by shock or strain, such as an earthquake, and results in temporary transforma- tion of the soil to a fluid mass. If the liquefying layer is near the f surface the effects are much like that of quicksand on any structure located on it. If the layer is in the subsurface, it may provide a sliding surface for the material above it. Liquefaction typically occurs in areas where the groundwater is less than 30 feet from the surface, and where_ the soils are composed predominantly of poorly consolidated fine sand. 1 - I Review of water-well records of the Coachella Valley County Water District and maps of the California Department of Water Resources (1964) indicates that groundwater levels in the study are and have been at or below 100 feet for several tens of years.. Considering the demand for water in the area, it is unlikely that water levels will rise to a depth that liquefaction vould become a potential hazard at Palm Desert. 3. Landslides Landslides should be considered a basic geologic hazard rather than one having an unusual association with earthquakes. The shaking of an earthquake only provides the triggering force to initiate down- slope movement of a previously unstable earthmass. The prime factor I is the unstable condition itself. Movement could just as easily be triggered by heavy rains, or by grading on a construction project. The bedrock underlying slopes steep enough to be involved in landsliding at Palm Desert is limited to relatively hard igneous and metamorphic types that are not generally prone to landsliding. The softer sedimentary rocks of the coastal sections of Southern California, in which landslides are common, are not present at Palm Desert. This dominance of relatively strong rock and the low annual rainfall make Ithe Palm Desert area one relatively free of landslides. Of the several types of landslides normally encountered in Southern California, only rockfalls (Figure 37) are present to any significant degree. They are common on the steeper slopes of the rocky terrain to the west and south of the City. A more detailed assessment of the landslide hazard at any particular site requires detailed knowledge of the site and the nature of any proposed modifications of the terrain. For this reason, engi- neering geologic and soils engineering investigations should be required for developments in hilly or mountainous terrains. It is only through detailed evaluation of existing conditions and proposed modifications that a high level of safety can be assured. E. TSUNAMIS AND SEICHES 1 Tsunamis are seismic sea waves, and do not present a hazard at Palm Desert. Seiches are standing waves produced in a body of water by the passage of seismic waves from an earthquake. Seiches are not a hazard because of the absence of lakes or reservoirs of significant size within the City. i i i` Jk Figure 37. Example of a rockfall type of landslide I 1 , L CONCLUSIONS AND RECOMMENDATIONS 1 . On the basis of existing information none of the faults within the City of Palm Desert can be considered "active" or "potentially I active" as presently defined by the State Mining and Geology Board and the State Geologist. 2. No Special Studies zones as required by the Alquist-Priolo Geologic Hazards Act have been delineated within the City by the State Geologist, and, based on the information developed in this study, none are expected. 3. The primary geologic hazard at Palm Springs is severe ground shaking as the result of major earthquakes on the Mission Creek branch of the San Andreas fault or the San Jacinto fault. 4. Information bearing on the risk of occurrence of earthquakes of various magnitudes on the San Andreas and San Jacinto faults are included in the text of the report. It is our recommendation Qe-- �l that planning and design of facilities for certain uses should take i into account the following earthquakes: Magnitude of Earthquake ! Use San Andreas Fault San Jacinto Fault I Critical Facilities 7. 5 7. 5 Normal Commercial Facilities 7. 0 6. 5 Normal Residential Facilities 6. 5 6. 5 5. Microzonation of the City is based on the distance to the earthquake- generating fault and the type of earth material present. The latter include bedrock, thick (200'+) alluvium; and thin (0-2001) alluvium. The generalized characteristics of expected shaking to be applied to each use in each of the eleven zones in the City are summarized i in Table 41of the text. The 18 response spectra are included as Figures 19 through 36. j 6. Settlement and liquefaction as a result of seismic shaking are not considered significant hazards in Palm Desert, provided soils engi- neering investigations are conducted by competent professionals on sites considered for structures. L_ 7. Soft sedimentary rocks, prone to landsliding in many other parts of California, are not present at Palm Desert, and this hazard is limited primarily to the rockfall types of landslide in the mountainous terrain in the western and southern part of the City. 8. Tsunamis and seiches are not a hazard at Palm Desert. I i i i l REFERENCES l Alford, J. L. , G. W. Housner & R. R. Martel, 1964, Spectrum analyses of strong-motion earthquakes: Earthquake Engineering Research Laboratory Report. Allen, C. R. , 1957 San Andreas fault zone in San Gorgonio Pass, Southern California: Geol. Soc. Amer. Bull. , v. 68, p. 315-350. 1 Allen, C. R. 1968, The tectonic environments of seismically active faults along the San Andreas fault system: in Proceedings of conference on geologic problems of the San Andreas fault system, Stanford Univ. , Pub, in the Geological Sciencer, x. XI, p. 70-82. Allen, C. R. , P. St. Amand, C. F. Richter, and J. M. Nordquist, 1965, Relationship between seismicity and geologic structure in the Southern California region: Seis. Soc. Am. , Bull. , v. 55, p. 753-797. I Allen, C. R. Max Wyss, J. N. Brune, A. Grantz and R. E. Wallace, 1972, Displacements on the Imperial Superstition Hills, and San Andreas i faults triggered by the Bonego Mountain earthquake; in in the Borrego Mountain earthquake, U. S. Geol. Survey Prof. Paper 787, p. 87-104. Bonilla, M. G. , 1970, Surface faulting and related effects: in Earthquake Engineering, R. L. Weigel, editor, Prentice-Hall, p. 47-74. Bonilla, M. G. , & J. M. Buchanan, 1970, Interim report on worldwide historic surface faulting: U. S. Geological Survey open-file report 32 p. California Council on'Intergovernmental Relations, 1973, General Plan Guidelines, September 20, 1973. -- California Department of Water Resources, 1964, Coachella Valley Investigation, Bulletin 108, 112 p. California Department of Water Resources, 1964, Crustal strain and fault movement investigation: Bulletin 116-2. I California Division of Mines & Geology, 1972 b, Preliminary earthquake epicenter map of California, 1934-June 30, 1971: Seismic Safety Information, 72-3, map scale, 1:1, 000, 000. i_ Clark, M. M. , A. Grantz, and M. Rubin, 1972, Holocene activity of. the Coyote Creek fault as recorded in sediments of Lake Cahuilla: U. S. Geol. Survey Prof. Paper 787, p. 112-130. Dickinson, W. R. , D. S. Cowan, and R.A. Schweickert, 1972, Test of new global tectonics: Discussion: Amer. Assoc. of Pet. Geol. , Bull. , v. 56, n. 2, p. 375-384. Duke, C. M. & D. J. Leeds, 1962, Site characteristics of Southern California strong-motion earthquake stations: U. C. L.A. Dept. of Engr. Rept. No. 62-55. Duke, C. M. , J. E. Luco, A. R. Carrivean, P. J. Hradilek, R. Lastnco and D. Ostrom, 1970, Strong earthquake motions and site conditions: Hollywood: Seis. Soc. Amer. Bull. , v. 60, n. 4, p. 1271 -1289. Duke, C. M. J.A. Johnson, Y Kharraz, K. W. Campbell, and. N.A. Malpiede, 1971, Subsurface site conditions and geology in the San Fernando earthquake area: School of Engr. & Spp. Sci. , Univ. of Calif. at Los Angeles, Report 7206, December, 1971, 118 p. Envicom Corporation, 1974, Seismic Safety Element, City of Palm Springs, California. i Frazier, D. M. 1931-, Geology of San Jacinto quadrangle south of San Gorgonio Pass, California: Calif. Div, of Mines Dept. 27, p. 494-540. Greensfelder, R. W. , 1972, Crustal movement investigations in California: their history, data and significance: Calif. Div. of Mines & Geology, Special Publication 37, 25 p. , map scale, 1:500, 000. Greensfelder, R. W. , 1973, A map of maximum bedrock acceleration from earthquakes in California: Calif. Div. of Mines & Geology. (Map and text are presently "Preliminary, subject to revision"). Hileman, J.A. , C. R. Allen, J. N. Brune, and Max Wyss, 1971, Measure- ment of active slip on faults in the Imperial Valley region, California, (abs. ): Program of the Cordilleran Section, Geol. Soc. America, 67th Ann. Meet. , Riverside, California. , p. 136. Hileman, J.A. , C. R. Allen, and J. M. Nordquist, 1973, Seismicity of the Southern California Region, 1 January, 1932 to 31 December, 1972: Calif. Inst, of Tech. Seis. Lab. , Pasadena, Calif. i Housner, G. W. , 1970, Strong ground motion: in Earthquake Engineering, R. L. Wiegel, editor, Prentice-Hall, p. 75-91 . Housner, G. W. , & M. D. Trifunac, 1967, Analysis of accelerograms - Parkfield earthquake: Seis. Soc. Amer. Bull. , v. 57, n. 6, p. 1193-1220. I Jennings, P. C. G. W. Housner, and N. C. Tsai, 1968, Simulated earthquake motions: Earthquake Engr. Res. Lab. Report, April 1968. Lamar, D. L. , P. M. Merifield & R. J. Proctor, 1973, Earthquake recur- rence intervals on major faults in Southern California: in Geology, Seismicity and Environmental Impact, Assoc. Engineering Geologists Spec. Pub. , Oct. 1973, D. E. Moran, J. E. Slosson, R. O. Stone & C.A. Yelverton, editors. Lastrico, R. M. 1970, Effects of site and propagation path on recorded strong earthquake motions: Unpub. Ph. D. dissertation, School of Engr, and App. Sci. , Univ. of Calif. at Los Angeles, 205 p. Matthiesen, R. B. , C. M. Duke, D. J. Leeds, & J. C. Fraser, 1964, Site characteristics of Southern California strong-motion earthquake stations, Part II: U. C. L.A. Dept. of Engr. Rept. No. 64-15. Miller, W. J. , 1944, Geology of the Palm Springs-Blythe strip, Riverside County, California: Calif. Jour. of Mines and Geology, vol. 40, p. 11-72. Murphy, L. M. and F. P. Ulrich, 1951, United States Earthquakes, 1948: U. S. Department of Commerce, 49 p. i Proctor, R. J. , 1968, Geology of the Desert Hot Springs-Upper Coachella Valley area, California: Calif. Div.. of Mines and Geology Spec. Dept. 94, 50 p. i Rodgers, T.H. , 1969, Geologic Map of California, Santa Ana Sheet: California Div. of Mines and Geology, 1:250, 000. Schnabel, P. , H. B. Seed and J. Lysmer, 1972, Modification of seismograph records for effects of local conditions: Seis. Soc. Amer. , Bull. , v. 62, n. 6, n. 1649-16 64. Schnabel, P. , and H. B. Seed, 1973, Accelerations in rock for earthquakes in the western United States: Seis. Soc. Amer. , Bull. , v. 63, n. 2, p. 501 -516. Seed, H. B. and I. M. Idriss, 1971, Simplified Procedure for evaluating soil liquefaction potential: Proceedings Amer. Soc. Civil Engineers, Jour. Soil Mechanics & Foundations Div. , v. 97, sm 9. i Sharp, R. V. , 1967, San Jacinto fault zone in the peninsular ranges of Southern California: Geol. Soc. Amer. Bull. , v. 78, p. 705-730. Sharp, R. V. , 1972, Map showing recently active breaks along the San Jacinto fault zone between the San Bernardino area and Borrego Valley, California: U. S. Geol. Survey Miscel. Geol. Invest. Map I-675, scale 1:24, 000. Sharp, R. V. , 1972 B, Tectonic setting of the Salton trough: in the Borrego Mountain earthquake of April 9, 1968, U. S. Geol. Survey Prof. Paper 787, p. 3-15. Sims, S. J. , 1961, Geology of part of the Santa Rose Mountains, Riverside County, California: unpublished Ph. D. dissertation, Stanford Univ. , . Stanford, California. Slosson, J. E. , 1973, Review of Special Studies Zones maps that delineate zones encompassing potentially active faults: Letter to Concerned Cities and Counties from the State Geologist, California Division of Mines and Geology, December 26, 1973. State Mining and Geology Board, 1973, Policies and Criteria of the State Mining and Geology Board with reference to the Alquist-Priolo Geologic Hazards Zones Act (Chapter 7. 5, Division 2, Public Resources Code, State of California): Adopted November 21, 1973, 3 p. Trifunac, M. D. , & J. N. Brune, 1970, Complexity of energy release during 4 the Imperial Valley, California, earthquake of 1940: Seis. Soc. Amer. Bull. , v. 60, p. 137-160. ` Trifunac, M. D. and D. E. Hudson, 1971, Strong motion records from the San Fernando earthquake; B. Analysis of the Pacoima Danz accelerograrn: in Engineering features of the San Fernando earthquake, February 9, 1971, Earthquake Engineering Research Laboratory Report 71 -02, P. C. Jennings, ed. , p. 110-139. U. S. Geological Survey, 1972, The Borrego Mountain earthquake of April 9, 1968: U. S. Geological Survey Prof. Paper 787, 207 p. Wood, H. O. & N. H. Heck (rev, by R.A Eppley), 1966, Earthquake history of the United States — Part II, Stronger earthquakes of California and western Nevada: U. S. Dept. of Commerce, 48 p. i f _ GLOSSARY OF TERMS 1 . 1 _ I i i Active Fault — One that has moved in recent geologic time and which is likely to move again in the relatively near future. Definitions for planning purposes extend on the order of 10, 000 years or more back and 100 years or more forward. IAlluvial — Pertaining or composed osed of alluvium or deposited b p � P Y a stream or running water. (AGI, 1972) Alluvium — A general term for clay, silt, sand, gravel or similar uncon- solidated detrital material deposited during comparatively recent geologic time by a stream or other body of running water as a sorted or semisorted sediment in the bed of the stream or on its flood plain or delta, or as a cone or fan at the base of a mountain slope. (AGI, 1972) Amplification — Elaboration;I augmentation; addition (Webster). As used herein, near-surface amplification is the augmentation of wave amplitude resulting from the change in physical properties in near-surface layers (see Introduction). Amplitude — The extent of the swing of a vibrating body on each side of the mean position. (Webster) Block Glide — A translational landslide in which the slide mass remains essentially intact, moving outward and downward as a unit, most often along a pre-existing plane of weakness such as bedding, foliation, joints, faults, etc. (AGI, 1972) Cohesion — Shear strength in a sediment not related to interparticle friction. (AGI, 1972) - Colluvium — (a) A general term applied to any loose, heterogenous, and incoherent mass of soil, material or rock fragments deposited chiefly by mass-wasting, usually at the base of a steep slope or cliff. (b) Alluvium deposited by unconcentrated surface runoff or sheet erosion, usually at the base of a slope. (AGI, 19 7 2) I_ Compaction — Reduction in bulk volume or thickness of, or the pore space within, a body of fine-grained sediments in response ' to the increasing weight of overlying material that is contin- ually being deposited, or to the pressure resulting from earth I movements within the crust. It is expressed as a decrease in porosity brought about by a tighter packing of the sediment — -- - particles. (AGI, 1972) i i Consolidated Material — Soil or rocks that have become firm as a result of compaction. Damping — The resistance to vibration that causes a decay of motion with 1 time or distance, e. g. the diminishing amplitude of an oscillation. I (AGI, 1972) IDifferential Settlement — Nonuniform settlement; the uneven lowering of different parts of an engineering structure, often resulting in damage to the structure. (AGI, 1972) Displacement (Geological) — The relative movement of the two sides of a fault, measured in any chosen direction; also, the specific amount of such movement. Displacement in an apparently lateral direc- tion includes strike-slip and strike separation; displacement in an apparently vertical direction includes dip-slip and dip separation. (AGI, 1972) Displacement (Engineering) — The geometrical relation between the position of a moving object at any time and its original position. (Webster) Epicenter — That point on the Earth' s surface which is directly above the focus of an earthquake. (AGI, 1972) Fault — A surface or zone of rock fracture along which there has been a displacement, from. a few centimeters to a few kilometers in scale. (AGI, 1972) IFault Surface — In a fault, the surface along which displacement has occurred. (AGI, 1972) Fault System — Two or more interconnecting fault sets, (AGI, 1972) Fault Zone — A fault zone is expressed as a zone of numerous small fractures or by breccia or fault zouge. A fault zone may be as wide as hundreds of meters. (AGI, 1972) Focus (Seism) — That point within the Earth which is the center of an earthquake and the origin of its elastic waves. Syn: hypocenter; seismic focus; centrum (see Introduction). (AGI, 1972) Ground Response —A general term referring to the response of earth materials to the passage of earthquake vibration. It may be expressed in general terms (maximum acceleration, dominant ----- - period, etc. ), or as a ground-motion spectrum. 4 I Hypocenter — See focus. Intensity (earthquake) — A measure of the effects of an earthquake at a particular place on humans and/or structures. The intensity at a point depends not only upon the strength of the earthquake, or the earthquake magnitude, but also upon the distance from the point to the epicenter and the local geology at the point. I (AGI, 1972) Isoseismal line — A line connecting points on the Earth's surface at which Iearthquake intensity is the same. It is usually a closed curve around the epicenter. 5yn: isoseism; isoseism.ic line; isoseismal. (AGI, 1972) g Liquefaction — A sudden large decrease in the shearing resistance of a q cohesionless soil, caused by a collapse of the structure by shock or strain, and associated with-a sudden but temporary increase of the pore fluid pressure. (AGI, 1972) i Macroseismic data — Used herein to describe instrumentally recorded earthquakes generally in the range of Richter magnitude 3. 0 or more. (This use differs from the AGI definition of "macro- seismic observations"). Magnitude (earthquake) — A measure of,the strength of an earthquake or the strain energy released by it, ,as determined by seismographic observations. As defined by Richter, it is the logarithm, to the base 10, of the amplitude in microns of the largest trade deflection that would be observed on a standard tortion seismograph (static magnification = 2800; period = 018 sec; damping constant = 0. 8) at a distance of 100 kilometers from the epicenter. (AGI, 1972) I Microseismic data — Used herein to describe instrumentally recorded earthquakes generally in the range of Richter magnitude 3. 0 or less. (This use is consistent with the AGI definition of microseism and microseismometer, but is more restricted than their definition of microseismic data). I Natural period — The period at which maximum response of a system. occurs. The inverse of resonant frequency. i Normal fault — A fault in which the hanging wall appears to have moved downward relative to the footwall. The angle of the fault is usually 45-90 degrees. This is dip-separation, but there may — - - or may not be sip-slip. (AGI, 1972) L I Predominant period — The period of the acceleration, velocity or displacement which predominates in a complex vibratory motion. In the analysis of earthquake vibrations, predom- inant period is normally the period of the maximum amplitude of the acceleration spectrum. Response spectrum — An array of the response characteristics of a structure or structures ordered according to period or frequency. The structures are normally single-degree-of- freedom oscillators, and the characteristics may be displace- ment, velocity or acceleration (see Introduction). Seiche — All standing waves on any body of water whose period is deter- mined by resonant characteristics of the containing basin as controlled by its physical dimensions. (U. S. Geol. Survey Prof. Paper 544-E) Seismic Seiche — Standing waves set up on rivers, reservoirs, ponds and lakes at the time of passage of seismic waves from an earthquake. (U. S. Geol. Survey Prof. Paper 544-E) I Shear — A strain resulting from stresses that cause or tend to cause contiguous parts of a body to slide relatively to each other in a direction parallel to their plane of contact; specifically, the ratio of the relative displacement of these parts to the dis- tance between them. (AGI, 1972) Shear-wave or S-wave — That type of seismic body wave which is propagated by a shearing motion of material so that there is oscillation perpendicular to the direction of propagation. It does not travel through liquids. (AGI, 1972) Slip — On a fault, the actual relative displacement along the fault plane of two formerly adjacent points on either side of the fault. Slip is three dimensional, whereas separation is two dimensional. (AGI, 1972) Strike-slip fault — A fault, the actual movement of which is parallel to P 1 the strike (trend) of the fault. (AGI, 1972) Subsidence — A local mass movement that involves principally the gradual downward settling or sinking of the solid Earth' s surface with little or no horizontal motion and that does not occur along a free surface (not the -result of a landslide or failure of a slope. --- (AGI, 1972) I Tectonic — Of or pertaining to the forces involved in, or the resulting structures or features of the upper part of the Earth' s crust. (mod. from AGI, 1972) Tsunami — A gravitational sea wave produced by any large-scale, short- duration disturbance of the ocean floor, principally by a shallow submarine earthquake, but also by submarine earth movement, 1 subsidence, or volcanic eruption, characterized by great speed of propgation (up to 950 km/hr.), long wavelength (up to 200 km.), f long period (5 min. to a few hours, generally 10 - 60 min. ), and ti low observable amplitude on the open sea, although it may pile up to great heights (30 m, or more) and cause considerable damage on entering shallow water along an exposed coast, often thousands of kilometers from the source. (AGI, 1972) + Unconsolidated material — A sediment that is loosely arranged or I unstratified or whose particles are not cemented together, occurring either at the surface or at depth. (AGI, 1972) Water table — The surface between the zone of saturation and the zone of aeration; that surface of a body of unconfined ground water at which the pressure is equal to that of the atmosphere. (AGI, 1972) I L I . TABLE A HAZARD COMPARISON OF NON-EARTHQUAKE-RESISTIVE BUILDINGS Relative Dar ageability Simplified Description (in order of increasing of Structural "..yp,2: wood-frame structures C Small w 1 i. e. dwellings 1 Inot over 3, 000 sq. ft. and not over 3 stories Single or multistory steel-frame buildings 1. 5 with concrete exterior walls, concrete floors, and concrete roof. Moderate wall openings Single or multistory reinforced-concrete 2 buildings with concrete exterior walls, con- crete walls) and concrete roof. Moderate wall openings ILarge area wood-frame buildings and other 3 to 4 wood frame buildings i Single or multistory steel-frame buildings 4 with unreinforced masonry exterior wall panels; concrete floors and concrete roof Single or multistory reinforced-concrete 5 I frame buildings with unreinforced masonry exterior wall panels, concrete floors and concrete roof Reinforced concrete bearing walls with 5 supported floors and roof of any material (usually wood) Buildings with unreinforced brick masonry 7 up having sand-line mortar; and with supported floors and roof of any material (usually wood) Colla sf h izard Bearing walls of unreinforced adobe, unrein- forced hollow concrete bloock, or unreinforced in mad- hollow clay tile sh�c{•' This table is intended for buildings not containing earthquake I and in general, is applicable to most older construction. U^:a•rc foundation conditions and/or dangerous roof tanks can increa5{: F::" earthquake hazard greatly. i I " I a •� E,-v_ o ..=S- th pass ! autt :. .. ....... �1 A r ' EXPLANATION T Zone boundary and zone designation ' TT based on distance. Zone boundary and zone designation �g C based on rock or soil type. A \ g "�`�• Fault; dashed where approximate; �JK dotted where buried. N. �\ TV- NNI 4 1 A 71.1. Cal :. j Z: aN /fj i