Seismic Velocities and Geologic Logs from Borehole Measurements at Seven Strong-Motion Stations That Recorded the 1989 Loma Prieta Earthquake

UNITED STATES DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY

SEISMIC VELOCITIES AND GEOLOGIC LOGS FROM BOREHOLE MEASUREMENTS AT SEVEN STRONG-MOTION STATIONS THAT RECORDED THE 1989 LOMA PRIETA EARTHQUAKE

U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 92-287 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American stratigraphic code). Any use of trade, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Menlo Park, California 1992 Seismic velocities and geologic logs from borehole measurements at seven strong-motion stations that recorded the Loma Prieta earthquake

James F. Gibbs1 , Thomas E. Fumal1 , David M. Boore1 , and William B. Joyner1

U.S. Geological Survey Open-File Report 92 - 287 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American stratigraphic code). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

1 U.S. Geological Survey, MS 977, Menlo Park, CA 94025 TABLE OF CONTENTS Page Introduction ...... 1

Field Measurements ...... 3 Geologic Logs ...... 4 Site Geology ...... 5 Travel-time Data ...... 6

Data Interpretation and Processing ...... 7

Summary of Results ...... 9 S-wave Velocities ...... 9 P-wave Velocities ...... 13

Acknowledgements ...... 16

References ...... 18 Appendices-Detailed Results: Alameda Naval Air Station ...... 20 Gilroy#2 (EPRI) ...... 34 Gilroy#2 (USGS) ...... 59 Oakland Outer Harbor Wharf ...... 72 San Francisco International Airport ...... 87 Treasure Island ...... 102 Palo Alto Veterans Hospital ...... 115 Yerba Buena Island ...... 129 Seismic velocities and geologic logs from borehole measurements at seven strong-motion stations that recorded the 1989 Loma Prieta earthquake by

Gibbs, James F., Thomas E. Fumal, David M. Boore, and William B. Joyner

INTRODUCTION The Loma Prieta earthquake of October 17, 1989 (1704 PST) was recorded at 131 strong-motion stations located through-out the San Francisco Bay area (Maley et al., 1989, Shakal, et al., 1989). This data set has enormous value for engineering and seismologi- cal studies regarding earthquake ground motions. Using shaking-damage to man-made structures from the 1906 San Francisco earthquake, Lawson (1908) recognized that ground motion intensity could be correlated with differences in local site geology. In order to quan tify the effect of local geology (Borcherdt, 1970; Borcherdt and Gibbs, 1976) on ground motions from the 1989 earthquake detailed geologic and geophysical data are needed. To plan the acquisition of these data a meeting was held on July 6, 1990 at the USGS in Memo Park, California. Eighteen scientist and engineers representing thirteen institutions attended the meeting to coordinate drilling and data aquisition plans at strong-motion stations. The USGS agreed to participate in geologic and geophysical data collection at sites drilled by other agencies. This report contains the results of the field effort by the USGS for the following eight boreholes (Figure 1). 1. Alameda Naval Air Station 2. Gilroy #2 (EPRI) 3. Gilroy #2 (USGS) 4. Outer Harbor Wharf 5. San Francisco International Airport 6. Treasure Island 7. Veterans Hospital - Palo Alto 8. Yerba Buena Island 10 O 10 20 3O 5O 70 SO Miles M M M l-l M k- =r~ E=T~

JO____2O____3Q____4O____SO____6O 7O____8O____9O 1OO Kilometers

Figure 1. Generalized map showing the locations of boreholes (triangles) included in this report. FIELD MEASUREMENTS Drilling and Sampling Procedures Drill sites in this study were chosen in order to provide detailed geologic, geophysical and geotechnical data at several "deep soil" sites and at two rock-soil site pairs, namely Yerba Buena Island (rock)- Treasure Island ("soft soil") and Gilroy #1 (rock)- Gilroy #2 ("stiff soil"). Gilroy #1 has been previouly investigated (Fumal et al, 1982) and is not included in this report. At each site a pilot hole approximately 5 inches in diameter was drilled for sampling purposes using rotary wash drilling with bentonite mud. At most sites this pilot hole penetrated about 15 meters into bedrock. At Gilroy #2 (USGS) and at Alameda Naval Air Station drilling was stopped about 1 to 2 meters into rock. At San Francisco International Airport, drilling was stopped 5 meters into rock because the bit twisted off. "Undisturbed" samples were taken inside Shelby tubes (3-inch outside diameter) using either a push sampler, a fixed piston (Osterberg) sampler, or a Pitcher barrel, depending on the stiffness of the sediment. These samples were allowed to drain of free water and sealed with wax plugs and endcaps. Standard penetration tests were carried out in sandy sediments above 30 meters in accordance with ASTM Standards D1586. Below 30 meters, penetration samples were taken with a 340 Ib. hammer and 2-inch inside diameter sampler. Rock cores (NX-size) were taken at Palo Alto Veterans Hospital, Oakland Outer Harbor Wharf and Yerba Buena Island. "Undisturbed" samples collected at Alameda Naval Air Station were taken by Dr. Kyle Rollins of Bringham Young University for testing. All samples taken at Palo Alto Veterans Hospital went to Wood ward-Clyde Consultants for analysis. Portions of penetrometer samples obtained at Treasure Island, Oakland Outer Harbor Wharf and San Francisco International Airport were sent to Professor I.M.'Idriss at the University of California at Davis. All other "undisturbed" samples went to Professor Kenneth Stoke of the University of Texas at Austin for testing. After completion of the pilot holes, the holes were reamed to 8 or 10 inches depending on the size of the casing installed. Gilroy #2 (USGS), Alameda Naval Air Station and Palo Alto Veterans Hospital were cased with 4-inch inside diameter, class 200, poly vinyl- chloride pipe capped at the bottom. The other sites were cased with 5-inch inside diameter polyvinyl-chloride pipe. The annular space around the casing was tremie grouted by pumping a water-cement - bentonite mixture through a 1-inch steel pipe installed next to the casing. This provides good coupling between the casing and the wall of the borehole, and provides a sanitary seal preventing contamination of ground water. Grouting; was done in stages of about 50-60 meters to prevent collapse of the casing. The California Division of Mines and Geology plans to install a strong-motion instrument package g,t the bottom of each 5-inch hole to i supplement surface recordings. Geologic Logs Geologic logs are based on descriptions of drill cuttings, samples, reaction of the drill rig, and inspection of nearby outcrops. Sedimelnt samples are described using the field techniques of the Soil Conservation Service (1951). Descriptions include sediment texture, color, and the amount and size of coarse fragments. Texture refers to the relative proportions of clay, silt, and sand particles less than 2 millimeters in diameter. This is determined visually and by feel without using labonitory tests. As such, this system is easier to use in the field than other classification systems. The dominant color of the sediment and prominent mottles are determined from the Munsell soil color charts. Descriptions of rock samples include rock name, weathering condition, color, grain size, hardness, and fracture spacing. Classifications o:' rock hardness and fracture spacing are those used by Ellen et al., (1972) in describing hillside materials in San Mateo County, California. Most information needed for describing relatively well-sorted soils and such properties of rock as lithology, color, and hardness are readily obtained from cuttings. Inspection of samples and nearby outcrops is necessary for determiijiing the nature of poorly-sorted ma terials and fracture spacing. Reaction of the drill rig ite useful in determining approximate sediment texture and in determining degree of fracturing because the rate of penetration in rock is highest for very closely fractured and crushed materials and drilling roughness generally is at a maximum in closely to moderately fractured rock. In-situ consistency of soil is determined largely from standard penetration measurements and rate of drill penetration. Site Geology The very near-surface geology at four of the sites, Alameda Naval Air Station, Oakland Outer Harbor Wharf, Treasure Island and San Francisco International Airport is similar, consisting of 1 to 13.5 meters of artificial fill overlying 1 to 15.5 meters of soft Holocene Bay mud. At the first three of these sites, these deposits are underlain by 55- to 130- meter thick sections of stiff Pleistocene Bay mud and clayey or sandy alluvial deposits. At San Francisco Airport, however, the Pleistocene Bay mud is only about 3 meters thick and the deposits underlying the Holocene Bay mud are almost entirely dense marine and continental sand. The near surface geology at the two "stiff soil" sites, Palo Alto Veterans Hospital and Gilroy #2 is quite dissimilar. Palo Alto Veterans Hospital is underlain by about 4 meters of Late Pleistocene alluvium overlying 128 meters of poorly sorted alluvium of the Santa Clara Formation. Gilroy #2 is underlain by 13 meters of Holocene alluvium, 8 meters of late Pleistocene alluvium and 18 meters of Pleistocene lacustrine deposits overlying poorly sorted alluvium of the Santa Clara Formation. The Santa Clara Formation at Gilroy #2 is generally coarser-grained than that at Palo Alto Veterans Hospital. Three deep holes have been drilled at Gilroy #2; we present results in this report for two of them. During Fall 1979, the USGS drilled a 182 meter deep hole at Gilroy #2. This hole bottomed 2 meters into hard sandstone, probably graywacke of the Franciscan assemblage similar to that underlying Gilroy #1. This hole was located about 100 meters northeast of the strong-motion recorder. No sampling was attempted in this hole. The Electric Power Research Institute funded a second deep hole (EPRI #1) during Fall 1990. This hole, located about 60 meters northeast of the strong-motion recorder, penetrated about 8 meters of firm sandstone of the Miocene Monterey Formation and 7 meters of sheared serpentinite. A third deep hole (EPRI #2) was drilled during fall 1991 in order to further investigate the bedrock. This hole, about 4 meters north of EPRI #1, penetrated 14 meters of siltstone, 11.5 meters of serpentinite and 50.5 meters of sheared to closely fractured shale and siltstone of the Franciscan assemblage. The serpentinite and sheared shale may be part of a fault zone named the Carnadero Fault by Dibblee and Brabb (1978). The geologic log from EPRI #2 is included for reference but at this time (March 1992) the USGS has not logged EPRI #2 for velocity data. The strong-motion instrument on Yerba Buena Island is located in a small building at the top of the cliffs on the southwest corner of tjie island. This building is founded on slightly weathered to fresh, moderately to widely fractured sandstone and minor shale of the Franciscan assemblage. Because of landscaping, the borehole is located about 160 meters north of the strong-motion instrument. This hole penetrated about 15 meters of deeply to moderately weathered sandstone. The fresh rock below 15 meters was largely very closely to closely fractured shale with some sandsi;one, and may be more characteristic of the material beneath the strong-motion recorder ihan is the weathered rock near the surface at the borehole site. Travel-time Data Shear waves* were generated at the ground surface by an air-powered horizontal ham mer (Liu, et al., 1988) striking anvils attached to the ends of a 2.3-meter-long aluminum channel. The hammer can be driven in both horizontal directions to generate positive and negative shear pulses. The switch that determines zero time is a piezo-electric sensor attached to the shear source. The source is offset from the borehole to prevent the direct arrival from traveling down the grout next to the casing. The source offset is 2 to 5 meters depending on the depth of the borehole. Shallow holes (30 meters or less) are generally offset 2 meters, while boreholes deeper than approximately 100 meters are offset 5 meters. Travel times are corrected (for slant offset) to vertical by the cosine of the angle of ray incidence. P-waves are made by striking a steel plate with a [sledge hammer at the same intervals described above. The recorder is triggered by the sledge hammer making electrical contact with the steel plate. Measurements are made by lowering a three-component geophone into the borehole and clamping it to the casing with an electrically actuated lever arm. A second three- component geophone is placed at the surface approximately 10 centimeters from the shear source and is used as a check of the switch triggering t!ie recorder for zero time. Depending

* In this report shear-wave(s) and S-wave are used interchangeably as well as P-wave and compressional-wave. on geologic information, measurements are repeated at 2.5 or 5.0 meter intervals. The 2.5 meter spacing is used when the layering of the sediments is thin (under 10 meters) and generally from the surface to 30 meters depth. The data are recorded on magnetic tape cassettes in digital form on a twelve channel recording system. DATA INTERPRETATION and PROCESSING The flow-chart, Figure 2, describes the processing and interpretation proceedures. The magnetic tape cassette contains 18 recorded traces from each depth. These include data from the surface three component geophone and the downhole three-component geophone: A total of 6 traces for each source type (positive horizontal, negative horizontal, and vertical). As mentioned previously, the surface geophone is used only to check timing. The orientation of the downhole geophone cannot be controlled when moving from one depth to the next, so that horizontal components are not generally oriented parallel and perpendicular to the source. This causes slight phase shifts, timing differences and amplitude variations. To minimize these effects, when timing shear-wave arrivals, the hor izontal components are combined (rotated) to obtain a single component of motion. The direction of motion is determined by maximizing the integral square amplitude within a time interval containing the shear wave (Boatwright et al., 1986). Rotated traces are plot ted on a 20-inch computer monitor and the first shear-wave arrival is timed for each of the horizontal rotated traces. Two arrival times are obtained from picks of positive and negative shear-wave arrivals. Timing of the arrivals is done to one millisecond precision. The two time-picks are not always identical, due to interfering waves obscuring the first shear-arrival, slight phase shifts, or amplitude differences. If the time difference is greater than about 5 milliseconds a mistake in phase correlation (perhaps due to a reversed trace, noise etc.) can be suspected and a repick may be necessary. The two picks are aver aged for velocity determinations. On clear traces one-millisecond picking accuracy can be maintained; however, because of lower signal-to-noise ratios and interfering waves in the deeper sections of the boreholes, this accuracy cannot always be achieved. The arrivals are weighted by the inverse of an assigned normalized variance. A normalized standard deviation of 1 was assigned to the accurate picks and values ranging up to 5 were assigned f START J

VIT

READ DATA FROM MAG CHOOSE LAYERS TAPE TO PC FROM GEOLOGIC LOG I

COMBINE ASCII \ 1 FILE AND CONTROL FILE LEAST-SQUARES FIT TO DATA PICKS ^ 1

CHANGE LAYERS

PLOT GRAPHS IRECORD SECTIONS) TIME-DEPTH

VELOCITY MODELS VELOCITY TABLES

Figure 2. Flow-chart outlining the data processing and interpretation steps

8 to the others. For determining the final velocity model there are a number of ways to proceed. In previous reports ( e.g., Gibbs et al., 1975) we determined the initial layer boundaries from the travel time plots by eye and then added or subtracted layers based on geologic boundaries consistent with the data. We also required at least three data points in each layer. This requirement limited the velocity determination to layers greater than 7.5 meters in thickness. The problem with this proceedure is that a mismatch (overlap or underlap) of the line segments sometimes occurred at the intersections of the layers, resulting in a discontinuous travel time curve. To address this problem we are now using a least-squares program (Press et al., 1986) that fits the travel time data with line segments hinged at each selected layer boundary from the surface (forced through zero) to the bottom data point. Initial layer boundaries are chosen from the geologic log and are adjusted, if necessary, to reduce residuals and for consistency with the data. The S-wave travel time data are analyzed first; layer boundaries are initially the same for the P-wave model, and are then adjusted, if necessary, by adding a layer for the water table or reducing the number of layers. The velocity plots (e.g. Figure 23) show upper and lower bounds which approximate 68% confidence limits. These bounds are not symmetrical because they are based on the standard deviation of the slope of the least-squares line fit to the travel time plots (the inverse of the velocity). SUMMARY OF RESULTS S-wave velocities Figure 3 summarizes shear-wave velocities obtained at the five sites in the San Fran cisco - Oakland area, four with thick sections of sedimentary deposits including Holocene bay mud and one rock site at Yerba Buena Island. Velocities measured in the present and previous investigations (Gibbs et al., 1976, 1977) suggest a linear increase in shear-wave velocity in Holocene bay mud with increasing thickness of overlying fill. The previous studies indicated shear-wave velocities of 100 meters/second or less for Holocene bay mud overlain by about 1 meter of fill and 145 meters/second for mud overlain by 7 meters of fill. Values obtained for bay mud in the study are: San Francisco Airport shear-wave velocity = 100 meters/second, with 2 meters of fill, Alameda Naval Air Station shear-wave velocity S Velocity (m/sec) 200 400 600 800 1000 <

Yerba Buena Island

San Francisco Airport 50-

E^ 100- xi Treasure Island Q.

Alameda Naval Air Station 150-

Outer Harbor Wharf

200

Artificial fill Holocene bay mud Pleistocene bay mud IH Pleistocene sand (Colma Fm./Merritt Sand) Figure 3. S-wave velocity models superimposed for comparison. The velocity below 15 meters at Yerba Buena Island is determined in fresh rock of the Franciscan assemblage. Velocities were not obtained in fresh Franciscan rock at the other sites. Shading indicates the geologic materials penetrated by the boreholes.

10 = 114 meters/second with 5 meters of fill, and Treasure Island shear-wave velocity = 177 meters/second with 13 meters of fill. Well determined velocities obtained for artificial fill ranged from 135 to 250 meter/second. Sedimentary deposits below 20 meters at Oakland Outer Harbor Wharf and about 30 meters at Treasure Island and Alameda Naval Air Station are predominantly Pleistocene estuarine clay, and the velocity profiles at these sites are very similar. Shear wave veloci ties obtained in the Pleistocene bay mud range from 200 meters/second at 27.5 meters to 365 meters/second at 140 meters. In contrast to the sites with large thicknesses of Pleis tocene bay mud (Alameda Naval Air Station, Oakland Outer Harbor Wharf and Treasure Island) sediments below 6.5 meters at San Francisco Airport are largely dense sands of the Colma Formation. Shear-wave velocities in these deposits are significantly higher than the Pleistocene clay at all depths, ranging from 260 meters/second at 6.5 meters to 770 meters/second at 150 meters. Unfortunately, we were unable to measure shear-wave velocity in unweathered rock at either Treasure Island or Oakland Outer Harbor Wharf due to poor transmission of energy across the sediment-bedrock interface and wave interference that obscured the shear wave arrivals. The value at Treasure Island (645 meters/second) is an average value for an interval containing both weathered and fresh rock. At Oakland Outer Harbor Wharf only one or two reliable measurements were obtained in rock so an average value was calculated for the sediments and rock below 131.5 meters. This should not be taken as indicating there is no velocity contrast at the sediment-rock interface, only that we were unable to resolve the contrast with our data. As noted earlier, the rock encountered in the borehole at Yerba Buena Island has a much thicker weathered zone and is more closely fractured than the rock underlying the strong-motion instrument site. Consequently, the velocities measured in the borehole are significantly lower than the expected values for the rock at the instrument site. Figure 4 summarizes the shear-wave velocities obtained at Palo Alto Veterans Hospital and Gilroy #2. Because interfering waves obscured the shear wave arrivals, we were unable to measure shear-wave velocity below 70 meters in the Gilroy #2 EPRI hole. The USGS Gilroy #2 borehole was drilled in 1979, when a preliminary velocity logging was done with

11 S Velocity (m/sec) 200 400 600 800 1000

50- Gilroy (EPRI)

(0 D Gilroy (USGS) 100-

OL 0> Q

150- VA Hospital (Palo Alto)

200

Figure 4. S-wave velocity models superimposed for comparison. The boreholes at Gilroy #2 (EPRI) and Gilroy#2 (USGS) are approkimately 50 meters apart and show some minor differences in velocity perhaps due to small variations in sediment thickness and to different mixtures of fine and coarse grained sediments.

12 measurements made at 20-meter intervals (Joyner, et al., 1981). When it was relogged in 1989 the casing was blocked at 120 meters (Gibbs, 1992). At Gilroy #2, the sedimentary deposits from about 21 to 40 meters consist of late Pleistocene lacustrine clay. Velocities in these deposits (270 to 335 meters/second) are slightly higher than those obtained for Pleistocene bay mud at these depths. Below these deposits and below about 4 meters at Palo Alto Veterans Hospital are poorly sorted fluvial and alluvial fan deposits of the Plio- Pleistocene Santa Clara Formation. Shear-wave velocities in these deposits range from 260 to 980 meters/second. The higher velocities correlate with higher percentages of gravel or a greater degree of cementation (Fumal 1978) in the lower parts of the deposits. P-wave velocities Figures 5 and 6 summarize compressional-wave velocities at the five northern sites and the two southern sites respectively. There is a poorer correlation between P-wave ve locity and lithology than S-wave velocity and lithology because P-wave velocity is strongly affected by degree of saturation. Note that even though saturated, the P-wave velocities measured in the Holocene bay mud are less than the velocity of P-waves in water (« 1500 meters/second). The explanation for this may be the presence of trapped gas (Brandt, 1960) has reduced the P-wave velocity (e.g. air, methane from decaying organic matter). The appendix lists the detailed results, organized alphabetically by borehole. Figures and tables for each site are arranged in the following order: 1. location map 2. geologic log 3. record sections 4. time-depth graph 5. velocity profiles 6. velocity tables

13 P Velocity (m/sec) 500 1000 1500 2000 2500 3000 t Yerba Buena Island

j San Francisco Airport

50-

Alameda Naval Air Station co .2"S E 100- Treasure Island CL

150- Outer Harbor Wharf

200

Figure 5. P-wave velocity models superimposed for comparison.

14 P Velocity (m/sec) 500 1000 1500 2000 2500 3000

VA Hospital (Palo Alto)

Gilroy (USGS) 50- |L

*»»CD

CL (D Q

150-

Gilroy (EPRI) 200

Figure 6. P -wave velocity models superimposed for comparison.

15 ACKNOWLEDGMENTS Funding for permitting, drilling, and casing for the eight borehole of this report was provided directly by seven different agencies and perhaps indirectly by others. Electric \ Power Research Institute (EPRI) provided funding for boreholes at Gilroy #2 and Yerba Buena Island under the sponsorship of Dr. John F. Schneider. The borehole at San Francisco Airport was co-funded by EPKI(Dr. John F. Schneider), University of California at Davis from a grant from several Japanese contracting companies (Professor I.M. Idriss), and the San JFrancisco International Airport Commission (Mr. Jason Yuen). The Treasure Island and Oakland Outer Harbor Wharf borehole? were co-funded by EPRI and the University of California at Davis. The Veterans Hospi tal (Palo Alto) borehole was funded by the U.S. Veterans Administration. The Alameda Naval Air Station borehole was drilled with funding provided by the National Science Foundation (Grant BCS-9011294) under sponsorship of Dr. Kyle M. Rollins and Brigham ifbung University with supplemental support from the University of California at Davis (Professor I.M. Idriss). The initial borehole to bedrock at Gilroy #2 was drilled in 1979 with funding by the USGS. Woodward-Clyde Consultants directed the drilling of all boreholes except the 1979 borehole at Gilroy, under contract with EPRI and the U.S. Veterans Administration. Drilling was arranged and coordinated by Dr. Joseph Sun and Mr. Peter Solberg under the direction of Dr. Lelio H. Mejia of Woodward- Clyde Consultants. Pitcher Drilling Company, Palo Alto, Ca drill :d all borings under contract with Wbodwardf-Ciyde Consultants except for the 1979 bo::ehole. Arrangements for funding of the investigation a San Francisco Airport site and co ordination with the airport were provided by Mr. Robert Darragh of Dames and Moore Consultants and Mr. Eddy T. Lau of Trans Pacific Qeotechnical Consultants, Inc. \ Many individuals contributed to the success of tide project at various stages, they in clude: Mr. John Belleau, Mr. and Mrs. Roger Elissondo (owner and managers of National 9 Inn for Gilroy #2), Mr. Gerald Serventi and Mr. David Herrick (Port of Oakland), Captain Knud Olsen (Maerslc Line, tenant at Port of Oakland), Mr. Vance Hendry (San .Francisco Airport), Mr. Donald Brown and Mr. A.E. Spencer (U.S. Naval Station Trea sure Island) , Chief Michael White (Ireasure Island fire chief), Lt. J.G. Ramires and Mr.

16 Patrick Layne (U.S. Coast Guard at Yerba Buena Island), and Dr. James C DeNiro and Mr. Alvin Seefeldt (Veterans Administration Hospital). In addition, Dr. Robert Darragh (CDMG/SMIP) assisted in locating strong-motion stations. Mr. Mark Barresi (Facilities Management Office, Alameda Naval Air Station), and Mr. Richard Ferris (Naval Facilities Command Western Division, San Bruno) helped with arrangements at Alameda Naval Air Station. We wish to thank Mr. Robert Westerlund of the USGS for building the electrically actuated clamp for the borehole geophone and for help in the field and Dr. Hsi-Ping Liu of the USGS for designing the shear-wave generator. In addition, we were assisted in the field by Mr. Michael Carter, Mr. Allyn Foss, and Mr. Thomas Powers of the USGS. The analysis of the data was facilitated by the graphics software of Scherbaum and Johnson (1990) and CoHort Software.

17 REFERENCES

Boatwright, John, R. Porcella, T. Fumal, and Hsi-Ping Liu, 1986, Direct estimates of shear wave amplification and attenuation from ^ borehole near Coalinga, California: Earthquake Notes, v.57, p.8. Borcherdt, R. D., 1970, Effects of local geology on ground motion near San Francisco Bay: Bull. Seismo. Soc. Am. v.60, pp.29-61. Borcherdt, Roger D., and James F. Gibbs, 1976, Effects of local geological conditions in the San Francisco Bay region on ground motions and the intensities of the 1906 earthquake: Bull. Seismo. Soc. Am. v.66, pp.467-500. Brandt, H., 1960, Factors affecting compressional wate velocity in unconsolidated marine sediments: Acoustical Soc. Am. Jour., v.32, pp^ 171-179. CoPlot, Scientific Graphics Software, CoHort Software, P.O. Box 1149, Berkeley, CA 94701. Dibble, Thomas W., and Earl E. Brabb, 1978, Preliminary geologic map of the Chittenden Quadrangle, Santa Clara, Santa Cruz and Safr Benito counties, California: U.S. Geological Survey Open-file Report 78-453. Ellen, S. D., C. M. Wentworth, E. E. Brabb, and E.i H. Pampeyan, 1972, Description of geologic units, San Mateo County, California: Accompanying U.S. Geological Survey Miscellaneous Field Studies Map, MF-328. Fumal, Thomas E., 1978, Correlations between seism:.c wave velocities and physical prop erties of near-surface geologic materials in the Southern San Francisco Bay region: U.S. Geological Survey Open-file Report 78-1067, 114p. Fumal, Thomas E., James F. Gibbs, and Edward F]. Roth, 1982, In-situ measurements of seismic velocity at 10 strong motion accelerojgraphs stations in central California: U.S. Geological Survey Open-file report 82-407, 76p. Gibbs, James F., 1992, The attenuation of seismic s hear waves in Quaternary alluvium from borehole measurements and local earthquakes, Santa Clara Valley, California: Annual meeting Seismo. Soc. Am., Santa Fe, NM. Gibbs, James F.,Thomas E. Fumal, and Roger D. Borcherdt, 1975, In-situ measurements of seismic velocities at twelve locations in the San Francisco Bay region: U.S. Geological Survey, Open-file report 75- 564, 87p. Gibbs, James F., Thomas E. Fumal, and Roger D. Borcherdt, 1976, In-situ measurements of seismic velocities in the San Francisco Bay Region...Part II, U.S. Geological Survey Open-file report 76-731, 145p. Gibbs, James F., Thomas E. Fumal, Roger D. Borcherdt, and Edward F. Roth, 1977, In-situ measurements of seismic velocities in the!San Francisco Bay Region...Part III, U.S. Geological Survey Open-file report 77-850, 143p.

18 REFERENCES (Continued) Joyner, William B., Richard E. Warrick, and Thomas E. Fumal, 1981, The effects of qua ternary alluvium on strong ground motion in the Coyote Lake, California earthquake of 1979: Bull. Seismo. Soc. Am., v.71, pp. 1333-1349. Lawson, A. C., (chairman), 1908, The California earthquake of April 18, 1906: Report of the State Earthquake Commission, Carnegie Inst. Washington. Liu, Hsi-Ping, Richard E. Warrick, Robert E. Westerlund, Jon B. Fletcher, and Gary L. Maxwell, 1988, An air-powered impulsive shear-wave source with repeatable signals: Bull. Seismo. Soc. Am., v.78, p.355-369. Maley, R., A. Acosta, F. Ellis, E. Etheredge, L. Foote, D. Johnson, R. Porcella, M. Salsman, and J. Switzer, 1989, U.S. Geological Survey strong-motion records from the northern California (Loma Prieta) earthquake of October 17, 1989: U.S. Geological Survey Open-file report 89-568. Press, William H., Brian P. Flannery, Saul A. Teukolsky, and William T. Vetterling, 1986, Numerical Recipes, the art of scientific computing, General Linear Least Squares: Cambridge University Press, Cambridge, p.509-515. Scherbaum, Frank and James Johnson, 1990, Programmable Interactive Toolbox for Seis- mological Analysis (PITSA): in IASPEI software library, Edited by W. H. K. Lee, distributed by Seismo. Soc. Am., El Cerrito, California 94530. Shakal, A., M. Huage, M. Reichle, C. Ventura, T. Cao, R. Sherburne, M. Savage, R. Darragh, and G. Peterson, 1989, CSMIP stong-motion records from the Santa Cruz Mountains (Loma Prieta), California earthquake of 17 October 1989: California De partment of Conservation, Division of Mines and Geology, Report OSMS 89-06. Soil Survey Staff, 1951, U.S. Department of Agriculture Handbook 18: U.S. Government Printing Office, Washington D.C. 20402, 503p. Terzaghi, Karl, and Ralph B. Peck, 1967, Soil mechanics in engineering practice: John Wiley and Sons, New York, 2nd edition.

19 UNITED STATES OAKLAND WEST QUADRANGLE DEPARTMENT OF THE INTERIOR CALIFORNIA GEOLOGICAL SURVEY 7.5 MINUTE SERIES (TOPOGRAPHIC)

OAKLAND OUTER HARBOR WHARF

SCALE 1:24000 o 1 MILE 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET I I I I I I t- -I ' I ' V- i ' \ KILOMETER

CONTOUR INTERVAL 20 FEET

Figure 7. Site location map for borehole at Alameda Naval Air Station and Oakland Outer Harbor Wharf. The borehole is located within 15 meters of the strong motion recorder.

20 Definitions of terms used for descriptions of sedimentary deposits and bedrock materials

Rock hardness: response to hand and geologic Texture:: the relative proportions of clay, silt, and hammer: (Ellen et al., 1972) sand belbw 2mm. Proportions of larger particles are indicated by modifiers of textural class names. hard hammer bounces off with solid sound Determination is made in the field mainly by feeling firm - hammer dents with thud, pick point dents or the moist soil (Soil Survey, Staff, 1951). penetrates slightly soft - pick points penetrates friable material can be crumbled into individual grains by hand.

Fracture spacing: (Ellen et al., 1972) cm in fracture soacina 0-1 0-1/2 v. close

1-5 1/2-2 close 5-30 2-12 moderate

30-100 12-36 wide >100 >36 v. wide

Weathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: Standard Munsell color names are given for discoloration the doninant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of samples structure is preserved. SP - Standard Penetration 1 + 3/8 in in ID sampler) S - Thin-wall push sampler Relative density of sand and consistency of clay is 0 - Osterberg fixed-piston sampler correlated with penetration resistance: (Terzaghi and P - Pitcier Barrel sampler Peck, 1948} CH - Ca ifornia Penetration (2 in ID sampler) DC - Dieimond Core

relative blows/ft. density blows/ft. consistencv

0-4 v. loose <2 v. soft

4-10 loose 2-4 soft

10-30 medium 4-8 medium

30-50 dense 8-15 stiff

>50 v. dense 15-30 v. stiff >30 hard

Figure 8. Explanation of geologic logs. 21 SITE: ALAMEDA NAVAL AIR STATION DATE: 5/20/91

UJ £ - 'Ul £0 . oo HI O DESCRIPTION o SAND, yellowish brown, well sorted, v. fine to fine grained (ARTIFICIAL FILL) _ ...... loose

32 IJSEjIiillJliiiJl olive, dense

5 CLAY, mottled, v.dk. gray and olive, v. son (HOLOCENE BAY MUD) S : r§r§:=:=| dk. greenish gray, abundant shells

?i-i-=-=-d-1 o ^ dk. olive to brown, peaty

v.dk. greenish gray, stiff

SAND TO LOAMY SAND, Oliver brown, v.fine to fine grained (MERRITT SAND) 15 S

507 SE

P~..;,,;..:::....

25______SAND TO LOAMY SAND, dk. greenish gray, v. fine to medium grained

p ...... with thin beds of SILTY CLAY

~~~ ^ ^ SILTY CLAY, v.dk. greenish gray, v. stiff______(PLEISTOCENE BAY MUD) 30' ~ "

Figure 9. Geologic log for Alameda Naval Air Station borehole.

22 SITE: ALAMEDA NAVAL AIR STATION DATE:

BLOWS/ GRAPHIC *^ SAMPLE I « FOOT TYPE LOG S ? DESCRIPTION ° £ ______I ______

OUon WI^MMM p &SF3

i-yKSii ^w SAND s -35

P&QrB= *»

-40 EW=§i^

^jd=y -45

-50

-55

rTS-^J-^Z i |_~=5!^_2|

DUfin

gure 9. (Continued). 23 SITE: ALAMEDA NAVAL AIR STATION DATE:

oo m

£815-65

dk. olive gray, abundant wood fragments ii-70

GRAVELLY SAND, mostly quartz, dk. gray sandstone, reddish brown chert

FINE SANDY LOAM, dk. greenish gray

GRAVELLY SAND

CLAY LOAM TO SILTY CLAY, v.dk. greenish gray, v. stiff

1-80

-85 u

-90

Figure 9. (Continued). 24 SITE: ALAMEDA NAVAL AIR STATION

DESCRIPTION

CLAY, olive gray, softer

CLAY LOAM to V.FINE SANDY CLAY LOAM, (PLEISTOCENE ALLUVIUM) It. olive brown, v. stiff it. yellowish brown

CLAY, greenish gray

CLAY LOAM, grayish brown

dk. greenish gray to greenis h gray

Figure 9. (Continued). 25 SITE: ALAMEDA NAVAL AIR STATION DATE SAMPE GRAPHIC BLOWS FOOT TYPE G LO £ DESCRIPTION

120-

-1

SAND, dk. gray to v.coarse size

130

SANDY CLAY LOAM, olive, v. stiff

-135

GRAVELLY SAND, olive gray

140

SHALE, black, hard (FRANCISCAN ASSEMBLAGE)

-145

-150

Figure 9. (Continued). 26 T. , x S-WAVfe Time (sec) Time (sec) 0 0.1 0.2 0.3 0.4 0.5 0 0.1 0.2 0.3 0.4 0.5 0.6 0

5 ^1|jf!)i$3pk^^ 7$ ^Xfe-^j^

10 80 15 85 V/I/W! 20 «^-^*^(WS??Kj II 90 -^^^5^ 1AA 25 30 ^ 100

§35 y 105 t=£8- 40 O 8-110 Q 45 \WyV-, 115 "~**s^^ ^ R 50 120 55 125 60 \JW 130 65 135 70 140 14$

Alameda Naval Air Station

Figure 10. Horizontal-component record section from impacts in opposite horizontal directions superimposed for identification of shear arrivals. S-wave arrivals are shown by the accent marks. An early arriving wave-train starts to build in amplitude at about 100 meters and continues to the bottom of the borehole; it is probably a tube wave traveling in the fluid-filled borehole. Identification of S-wave arrivals below 100 meters, although slightly lower in frequency than the earlier arriving energy, is less certain due to interference by the early arriving wave.

27 P-WAVE Time (sec), x Time (sec) 0.1 0.2 0.3 0.4 0 0.1 0.2 0.3 0.4 0

5 75 10 4vVl/l^^ 80 15 -^KV^^ ^ 85

20 -At^Ji^ 90 -~-V|/\/Wv^^

25 95 30 l\j\^\l^^ _ 100 35 /\J\f^\j]j^ ^105 ^i 40 l\jV^fj\f^i^^ g-110 Q Q 45 115 50 120 55 -t\J^\flT^\j^^ ^V 125 60 -^l\I\tf\-*l^^ 130 65 135 70 140 145

Alameda Naval Air Station

Figure 11. Vertical component record section. P-wave arrivals are shown by the solid circles.

28 Time (sec) 0.1 0.2 0.3 0.4 0.5 I

50- co £"5

150-

Alameda Naval Air Station Figure 12. Time-depth graph of P-wave and S-wave picks. Line segments show the hinged-least-squares fit to the data points.

29 S Velocity (m/sec) 100 200 300 400 500 600

(ARTIFICIAL FILL) r (HOLOCENE BAY MUD) SANO TO LOAMY SAND (MERRITT SAND)

LOAMY SAND, with thin beds of SILTY CLAY SILTY CLAY (PLEISTOCENE BAY MUD)

50-

(O .2"o FINE SANDY LOAM GRAVELLY SAND CLAY LOAM TO SILTY CLAY o.

CLAY CLAY LOAM

SAND

SANDY CLAY LOAM

GRAVELLY SAND SHALE (FRANCISCAN ASSEMBLAGE) 150-

Alameda Naval Air Station

Figure 13. S-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

30 P Velocity (m/sec) 500 1000 1500 2000

SAND (ARTIFICIAL FILL)

(HOLOCENE BAY MUD)

SAND TO LOAMY SAND (MERRITT SAND)

LOAMY SAND, with thin beds of SlLTY CLAY

SILTY CLAY (PLEISTOCENE BAY MUD)

50-

FINE SANDY LOAM GRAVELLY SAND E CLAY LOAM TO SILTY CLAY

CLAY CLAY LOAM

SAND

SANDY CLAY LOAM

GRAVELLY SAND (FRANCISCAN ASSEMBLAGE) 150-

Alameda Naval Air Station Figure 14. P-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

31 TABLE 1 . S-wave arrival times and velocity summaries for Alameda Naval Air Station.

d(m) d(ft) t(sec) slg rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0125 1 .0 .0 .0 .000 200 184 219 656 603 719 5.0 16.4 .0315 -.3 2.5 8.2 .012 200 184 219 656 603 719 7.5 24.6 .0541 .3 5.0 16.4 .032 130 121 140 425 396 459 10.0 32.8 .0760 .2 13.5 44.3 .107 114 111 116 373 366 381 12.5 41.0 .0975 -.2 17.5 57.4 .116 431 377 502 1413 1237 1647 15.0 49.2 .1100 .0 27.5 90.2 .145 339 325 353 1112 1068 1159 17.5 57.4 .1149 -.9 40.0 131.2 .206 206 202 210 676 664 689 20.0 65.6 .1237 .5 60.0 196.9 .283 258 254 262 847 833 861 22.5 73.8 .1313 .7 72.0 236.2 .322 310 299 323 1018 980 1059 25.0 82.0 .1388 .8 78.2 256.6 .339 376 343 414 1232 1127 1359 27.5 90.2 .1441 -1.2 98.8 324.1 .398 344 337 352 1130 1104 1156 30.0 98.4 .1574 -.1 140.0 459.3 .511 366 360 373 1202 1181 1224 35.0 114.8 .1822 .5 40.0 131.2 .2054 -.6 45.0 147.6 .2251 -.2 50.0 164.0 .2453 .6 CO 55.0 180.4 .2649 .8 ro a0-0 196.9 .2825 -1.0 1X3 65.0 213.3 .3001 .5 Explanation: 70.0 229.7 .3147 -1.0 75.0 246.1 .3313 1.2 d(m) = depth in meters 80.0 262.5 .3428 -1.1 d(ft) = depth in feet 85.0 278*9^ .3594 1 1.0 90.0 295.3 .3714 -1.5 t(sec) =^nrrvai time in seconds (S-wave~amval times are 95.0 311.7 .3895 2.1 the average of picks from traces obtained from 100.0 328.1 .4055 2 1.9 105.0 344.5 .4135 1 -1.9 hammer blows differing in direction by 180°) 110.0 360.9 .4286 1 -.4 sig = sigma, standard deviation normalized to the 115.0 377.3 .4411 2 -.8 120.0 393.7 .4566 2 .1 standard deviation of best picks 125.0 410.1 .4701 2 .1 rsdl/sig = least-squares residual divided by sigma 130.0 426.5 .4861 2 1.2 135.0 442.9 .4982 3 .3 dtb(m) = depth to bottom of layer in meters 140.0 459.3 .5102 3 -.2 dtb(ft) = depth to bottom of layer in feet ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

ANS.S 2-20-92 2:22p Pag* 1 of 1 TABLE 2. P-wave arrival times and velocity summaries for Alameda Naval Air Station.

d(fli) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0072 2 .2 .0 .0 .000 368 342 397 1207 1123 1303 5.0 16.4 .0099 2 .1 2.5 8.2 .007 368 342 397 1207 1123 1303 7.5 24.6 .0125 2 .0 13.5 44.3 .019 869 829 913 2851 2719 2997 10.0 32.8 .0152 1 -.2 27.5 90.2 .029 1516 1459 1577 4973 4786 5175 12.5 41.0 .0176 1 -.7 40.0 131.2 .037 1552 1485 1625 5092 4873 5331 15.0 49.2 .0209 1 .5 60.0 196.9 .049 1668 1613 1727 5472 5291 5665 17.5 57.4 .0221 .0 72.0 236.2 .057 1467 1410 1528 4812 4625 5014 20.0 65.6 .0243 .6 140.0 459.3 .095 1803 1788 1818 5915 5868 5963 22.5 73.8 .0254 .0 25.0 82.0 .0275 .5 27.5 90.2 .0285 -.2 30.0 98.4 .0296 -.7 35.0 114.8 .0337 .2 40.0 131.2 .0367 .0 45.0 147.6 .0398 .1 50.0 164.0 .0428 .1 CO 55.0 180.4 .0458 .1 CO 60.0 196.9 .0488 .1 65.0 213.3 .0518 -.3 Explanation: 70.0 229.7 .0559 .3 75.0 246.1 .0589 .3 d(m) = depth in meters 80.0 262.5 .0609 -.5 d(ft) = depth in feet 85.0 278.9 .0639 -.2 90.0 295.3 .0669 .0 t(sec) = arrival time in seconds (S-wave arrival times are 95.0 311.7 .0699 .2 the average of picks from traces obtained from 100.0 328.1 .0729 .4 105.0 344.5 .0749 -.3 hammer blows differing in direction by 180°) 110.0 360.9 .0769 -.5 sig = sigma, standard deviation normalized to the 115.0 377.3 .0809 .1 120.0 393.7 .0839 .4 standard deviation of best picks 125.0 410.1 .0859 -.4 rsdl/sig = least-squares residual divided by sigma 130.0 426.5 .0889 -.2 135.0 442.9 .0919 .0 dtb(m) = depth to bottom of layer in meters UO.O 459.3 .0949 .3 dtb(ft) = depth to bottom of layer in feet ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

ANS.P 2-20-92 2:20p Page 1 of 1 WATER STORAGE TANK & WELL PUMP

STOCKPILE

FIELD

WELL PUMP WATER STORAGE TANK "-XV - EPRI 2^ A

BUILDING (ADJOINING PROPERTY) MOTEL ROOMS

LANDSCAPING

PAVEMENT

OFFICE FILTER HOUSE CDMG INSTRUMENT

WONTEREY STREET

Project No. EPRI Fi«ld Exploration 90CQ588A SITE PLAN Wood ward-Clyde Consultants GILOROY NO. 2

Figure 15. Detailed site location of Gilroy #2. Notice the location of EPRI and USGS boreholes relative to strong-motion recorder. 34 UNITED STATES DEPARTMENT OF THE INTERIOR _ GEOLOGICAL SURVEY

Monterey "^ shale U Late Pleistocene /DHII\ i \ \ alluvium \ i \ l s*^^*-i; "^^rvmr serpentinite

GILROY #2

Holocene alluvium

Franciscan sandstone

Franciscan greenstone ted

SCALE 1:24000 o 1 MILE

1000 1000_____2000_____3000 4000 5000 6000_____7000 FEET i -i i i i i i 1 KILOMETER i i I

PIEIIMINAIT CEOIOCIC iAP OF TIE CIITTENDEN QOADIAN61E, SANTA CLAIA, SANTA CIUZ IND SAN IENITO COUNTIES. CHIFOINIA BT Thomas W.^DibW**?" Jr. and Earl E. Brabb 1978

Figure 16. Site location map for Gilroy #2.

35 Definitions of terms used for descriptions of sedimentary deposits and bedrock materials

Rock hardness: response to hand and geologic Texture: the relative proportions of clay, silt, and hammer: (Ellen et al., 1972) sand below 2mm. Proportions of larger particles are indicated by modifiers of textural class names. hard - hammer bounces off with solid sound Determination is made in the field mainly by feeling firm - hammer dents with thud, pick point dents or the moist soil (Soil Survey, Staff, 1951). penetrates slightly soft - pick points penetrates friable material can be crumbled into individual grains by hand.

Fracture spacing: (Ellen et al., 1972) cm in fracture soacina 0-1 0-1/2 v. close

1-5 1/2-2 close 5-30 2-12 moderate 30-100 12-36 wide

>100 >36 v. wide

Weathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: Standard Munsell color names are given for discoloration the dominant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of samples structure is preserved. SP - Standard Penetration 1 + 3/8 in in ID sampler) S - Thin-wall push sampler Relative density of sand and consistency of clay is 0 - Ostcrberg fixed-piston sampler Correlated with penetration resistance: (Terzaghi and P - Pitcher Barrel sampler Peck, 1948) CH - California Penetration (2 in ID sampler) DC - Diarnond Core

relative blows/ft. density blows/ft. consistency

0-4 v. loose <2 v. soft

4-10 loose 2-4 soft 10-30 medium 4-8 medium

30-50 dense 8-15 stiff

>50 v. dense 15-30 v. stiff >30 hard

Figure 17. Explanation of geologic log for Gilroy #2 (EPRI #1).

36 SITE: GILROY *2 EPRI 1 DATE: 9/21/90 BLOWS/ SAMPLE GRAPHIC *^ FOOT i £ TYPE LOG i 5 DESCRIPTION °3 -o SANDY LOAM, dk. yellowish brown (HOLOCENE ALLUVIUM)

_ dk. gray to dk. grayish brown

S BiBl -5 __-____.- "IT i__ __ _ SILTY CLAY LOAM, dk. grayish brown to brown

' '.> :' y.^.v'' S LOAMY FINE SAND, brown, medium to coarse grained :'' ' ' '. ' " t :' -10 . .: :

' /.' / X ' . A*

-' ''. ' '? ' '." .' S SAND, well sorted, v. coarse grained, some gravel ...... " CLAY, pale brown, v.stiff (LATE PLEISTOCENE ALLUVIUM)

_15 SAND P m SANDY FINE GRAVEL, brown, mostly graywacke fragments >&&* MM S®8S £?:<£o> s^o°61 98S&- tt*W °>^ -20 >-$,v.o\' 3S8S? CLAY, yellowish brown (PLEISTOCENE LAKE DEPOSITS) ~P~ M dk. greenish gray, v. stiff

-25

P 7°^^^==

=B:^=^sPs r~P~" ^l=-^=~

on ..,__, \J\J

Figure 18. Geologic log for Gilroy #2 (EPRI #1).

37 SITE: GILROY *2 EPRI 1 DATE: SAMPLE QRAPHIC BLOWS FOOT TYPE LOQ DESCRIPTION

p ...... - <-. FINE SANDY LOAM, dk. greenish gray

SILTY CLAY, v. dk. greenish gfay -35

11^

SANDY LOAM

-40 GRAVELLY SAND, strong bro>jvn, dense PLEISTOCENE ALLUVIUM

P~^,?_''~_

*""'""'"" 45

GRAVEL

GRAVELLY SAND, yellowish bjrown

1-50 GRAVEL - f9&&i£ P , T _ .(

IrSSS" 55 $£&* GRAVELLY SAND, yellowish brown

SANDY CLAY, brown to strong brown

Figure 18. (Continued). 38 SITE: GILROY *2 EPRI 1 DATE:

UJ I- o 00 o. *; DESCRIPTION -I U. oc GO o 60

GRAVEL Kr;.Vfcv.y?L pmr GRAVELLY SAND, yellowish brown -[ ".- ;". ".-, >65 GRAVEL iil_

70^ GRAVELLY SAND

fefl^i^fiJ *' f*M . GRAVEL

SAND CLAY GRAVEL 75 GRAVELLY SANDY CLAY LOAM, olive brown, v.poorly sorted

H. if -/i **i

* » V^.^jV

g^j t ,"4i [ O'

^ KE pfiy; K

v^rIB j^jyr

''» i"- 1'. '.'.'.'.'.' t.i'.'-'.w-'Z?: GRAVEL

^fe^~ GRAVEL

Figure 18. (Continued). 39 SITE: GILROY *2 EPRI 1 DATE:

UJ a.tr *- 00 ui « DESCRIPTION -111. Q E CD $ 90- GRAVEL, dk. yellowish brown, v.poorly sorted, texture of matrix is SANDY CLAY LOAM

SANDY CLAY LOAM

GRAVEL

SANDY CLAY LOAM

-100

105 DH SANDY CLAY, strong brown SANDY CLAY, occasional thinl lenses of gravel

SANDY CLAY LOAM, v. dense, v. poorly sorted GRAVEL SANDY CLAY _ t GRAVELLY SANDY CLAY LOAM, brown, v. dense 3* ' ^ 120

Figure 18. (Continued). 40 SITE: GILROY *2 EPRI 1 DATE: BLOWS/ SAMPLE QRAPHIC z * FOOT TYPE LOQ i | DESCRIPTION

120 ::y.^v>. f.\'t!.'^''. ' ' :.

tftifat. *j'fr'.'' .' .'> a-'-£ife -125 &&: % I'...'.? ££'.''%

L>H ft P

I** -1 ^n

&! '. !';'.'!.'".- '!

M?K^-; y!1.'..'1. .'' : .'' '' - * >'!.:' .. '.' T'V ^^- ^ '

r^-r'ft:.1: -1 ^*5 * ". *"*^- * * - .". * j * | " -* '/ Y.-J'*?"Cr '«': * *" /.'! ' ' . >" 'I Vi .'i

' . v** - ; ! .;.". '. 1 ' l'«"',f^" ',-'

-140 jOy.>.-^'.-' '.'.'.' Mt''1 ".^. . '-.' '. . . .' . '..:. ._ ', ' _»?' * - * ' .^-

O'CS'-r-'^ - GRAVEL

-145

p l%«

i * " "^' * 1' ' i _ . . . ; . . ^ ." < .^. . '. ''.i :-^vi;

Figure 18. (Continued). 41 BLOWS/ FOOT CO 00 SAMPLE H TYPE m O GRAPHIC I5* LOG DEPTH gr- 03 N O) O> Ol (meters) o 01 01 O CO o CO 3D m 3D CO TJ o m * m z z m < a- m Z I O m o m 10 o <>> CO Q. ~o I (D (Q 0.

(D W o CO H Z o O m H m o 30 m

CO in S-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 0.4 0.5 0 0.1 0.2 0.3 0.4 0.5 o 5 95 10 100 15 105 20 110 >^)!^ 25 115 ^^^^^^ 30 120 35

80 170 ^y^/W-vv 85 175 AA^^^^^^ 90 180

Gilroy #2, EPRI Borehole Figure 19. Horizontal-component record section from impacts in opposite horizontal directions superimposed for identification of shear arrivals. S-wave arrivals are shown by the accent marks. An early arriving wave-train starts to build in amplitude at about 70 meters and continues to the bottom of the borehole. Interference to S-wave arrivals below 70 meters made picks too uncertain for velocity determinations .

43 P-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 0 .4 0 0.1 0.2 0.3 0.4 0 5 95 10 100 15 105 f^ yM/\jW\*/^s^s^^ -^^^^^^. 20 110 25 115 30 120 -p- ^/vl/l/\Ayv/\/y~>/wv-.*^^ - - 35 125 E 4° P* 130 r 45 ^ 135 fvx 'vJ\ly\f(J\/*f^^^ 8- 50 /\jjw%iii/^./Vv/v'v/^ ^"^ 0.140 Q 55 Q 145 60 150 65 155 70 160 75 165 80 170 85 175 90 180

Gilroy #2, EPRI Borehole

Figure 20. Vertical-component record section. P-waves are shown by the solid circles.

44 Time (sec) 0.05 0.1 0.15 0.2 0.25 0.3 I

50-

100 J

150 H

200

Gilroy (EPRI Hole)

Figure 21. Time-depth graph of P-wave and S-wave picks. Line segments show the hinged-least-squares fit to the data points.

45 S Velocity (m/sec) 200 400 600 800

SANDY LOAM (HOLOCENE ALLLUVIUMI

SILTY CLAY LOAM

LOAMY SANO

(LATE PLEISTOCENE ALLUVIUM) ANOY FINE GRAVEL

(PLEISTOCENE LAKE DEPOSITS]

FINE SANDY LOAM SILTY CLAY SANDY LOAM GRAVELLY SAND PLEISTOCENE ALLUVIUM 50- 23C GRAVEL 5^2 GRAVEL

GRAVELL SANDY C

GRAVELLY SAND

(O GRAVELLY SANDY CLAY LOAM

SANDY CLAY LOAM GRAVEL 100- SANDY CLAY LDAM

GRAVELLY SANDY CLAY LOAM

150-

(MONTEREY SHALE)

Gilroy (EPRI Hole)

Figure 22. S-wave velocity profiles with dashed 1 nes representing plus and minus one standard deviation. The statistics are done on the sl

46 P Velocity (m/sec) 1000 2000 3000

(HOLOCENE ALLLUVIUM!

SILTY CLAY LOAM

LOAMY SAND

CLAY (LATE PLEISTOCENE ALLUVIUM! *$?.*SANDY FINE GRAVEL

(PLEISTOCENE LAKE DEPOSITS!

I FINE SANDY LOAM 5- SILTY CLAY ' SANDY LOAM GRAVELLY SAND PLEISTOCENE ALLUVIUM 50- SjCTcRAVEL

1 GRAVELLY SAND m. co GRAVELLY SANDY CLAY LOAM .2"55

SANDY CLAY LOAM E .GRAVEL 100- SANDY CLAY LOAM

CL GRAVELLY SANDY CLAY LOAM

150-

(MONTEREY SHALE!

SERPENTINITE

Gilroy (EPRI Hole)

Figure 23. P-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope of the line segments (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

47 TABLE 3. S-wave arrival times and velocity summaries for Gilroy #2 (EPRI #1).

d(m) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0143 -.1 .0 .0 .000 173 166 182 569 544 596 5.0 16.4 .0237 .6 2.5 8.2 .014 173 166 182 569 544 596 7.5 24.6 .0333 -.8 5.6 18.4 .025 288 265 316 946 869 1038 10.0 32.8 .0465 .5 13.0 42.7 .060 212 206 217 694 677 712 12.5 41.0 .0566 -1.2 21.4 70.2 .076 517 494 542 1697 1621 1780 15.0 49.2 .0645 .5 32.5 106.6 .118 267 263 272 878 862 893 17.5 57.4 .0702 1.3 39.4 129.3 .140 318 303 334 1042 993 1095 20.0 65.6 .0738 .1 50.0 164.0 .162 468 443 496 1536 1453 1629 22.5 73.8 .0795 -1.0 70.0 229.7 .194 630 591 674 2066 . 1938 2213 25.0 82.0 .0892 -.7 27.5 90.2 .0999 .7 30.0 98.4 .1090 .5 4* 32.5 106.6 .1176 -.3 00 35.0 114.8 .1257 1 -.1 37.5 123.0 .1323 2 -.7 Explanation: 40.0 131.2 .1414 2 .3 42.5 139.4 .1470 2 .4 d(m) = depth in meters 45.0 147.6 .1516 2 .0 d(ft) = depth in feet 47.5 155.8 .1571 2 .1 50.0 164.0 .1622 2 .0 t(sec) =:^MTivai time in seconds {S-wave arrival times are 52.5 172.2 .1662 2 .0 the average of picks from traces obtained from 55.0 180.4 .1698 2 -.2 57.5 188.6 .1738 2 -.2 hammer blows differing in direction by 180°) 60.0 196.9 .1784 2 .1 sig = sigma, standard deviation normalized to the 65.0 213.3 .1869 3 .3 70.0 229.7 .1930 5 -.2 standard deviation of best picks rsdl/sig = least-squares residual divided by sigma dtb(m) = depth to bottom of layer in meters dtb(ft) = depth to bottom of layer in feet ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

GIL.S 2-20-92 2:36p Pa0« 1 of 1 TABLE 4. P-wave arrival times and velocity summaries for Gilroy #2 (EPRI #1).

d(m) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0080 1 .0 .0 .0 .000 312 298 327 1023 976 1074 5.0 16.4 .0134 1 .1 2.5 8.2 .008 312 298 327 1023 976 1074 7.5 24.6 .0166 1 -.1 5.6 18.4 .015 474 437 517 1554 1432 1697 10.0 32.8 .0197 1 .1 13.0 42.7 .023 872 822 929 2862 2697 3048 12.5 41.0 .0223 1 -.2 21.4 70.2 .035 725 699 754 2380 2293 2474 15.0 49.2 .0256 1 -.2 32.5 106.6 .041 1673 1573 1787 5488 5159 5863 17.5 57.4 .0298 1 .5 39.4 129.3 .045 2095 1865 2391 6874 6118 7844 20.0 65.6 .0330 .3 50.0 164.0 .050 2137 1991 2307 7013 6532 7570 22.5 73.8 .0351 -.2 73.0 239.5 .061 1955 1908 2003 6413 6261 6572 25.0 82.0 .0363 -.5 155.0 508.5 .101 2083 2067 2099 6833 6781 6886 27.5 90.2 .0384 .1 166.7 546.9 .107 1752 1623 1905 5749 5324 6248 30.0 98.4 .0395 -.3 180.0 590.6 .113 2291 2000 2682 7517 6562 8799 32.5 106.6 .0415 .2 35.0 114.8 .0426 .1 37.5 123.0 .0436 .0 40. 0 131.2 .0447 -.1 42. 5 139.4 .0457 -.3 45. 0 147.6 .0477 .5 47.5 155.8 .0487 .4 50.0 164.0 .0498 .3 52.5 172.2 .0508 .0 55.0 180.4 .0518 -.3 57.5 188.6 .0528 -.6 60.0 196.9 .0548 .2 4*fc 65.0 213.3 .0568 -.4 CD 70.0 229.7 .0589 -.8 75.0 246.1 .0629 .7 Explanation: 80.0 262.5 .0649 .3 85.0 278.9 .0669 1 -.1 d(m) = depth in meters 90.0 295.3 .0699 1 .5 d(ft) = depth in feet 95.0 311.7 .0719 1 .1 100.0 328.1 .0739 1 -.3 t(sec) = arrival time in seconds (S-wave arrival times are 105.0 344.5 .0769 1 .3 the average of picks from traces obtained from 110.0 360.9 .0789 1 -.1 115.0 377.3 .0809 1 -.5 hammer blows differing in direction by 180°) 120.0 393.7 .0839 .1 sig = sigma, standard deviation normalized to the 125.0 410.1 .0869 .7 130.0 426.5 .0889 .3 standard deviation of best picks 135.0 442.9 .0919 .9 rsdl/sig = least-squares residual divided by sigma 140.0 459.3 .0929 -.6 145.0 475.7 .0959 .0 dtb(m) = depth to bottom of layer in meters 150.0 492.1 .0979 -.4 dtb(ft) = depth to bottom of layer in feet 155.0 508.5 .0999 2 -.4 160.0 524.9 .1029 2 -.3 ttb(s) = arrival time in seconds to bottom of layer 165.0 541.3 .1060 2 -.2 v(m/s) = velocity in meters per second 167.5 549.5 .1080 2 .2 170.0 557.7 .1090 2 .1 vl(m/s) = lower limit of velocity in meters per second * 172.5 565.9 .1100 2 .1 vu(m/s) = upper limit of velocity in meters per second 175.0 574.1 .1110 2 .0 177.5 582.3 .1120 2 .0 v(ft/s) = velocity in feet per second 180.0 590.6 .1130 2 -.1 vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

G1L.P 2-20-92 2:23p Pago 1 of 1 Definitions of terms used for descriptions of sedimentary deposits and bedrock materials

Rock hardness: response to hand and geologic Texture: the relative proportions of clay, silt, and hammer: (Ellen et at. 1972) sand below 2mm. Proportions of larger particles are indicated by modifiers of textural class names. hard - hammer bounces off with solid sound Determination is made in the field mainly by feeling firm - hammer dents with thud, pick point dents or the moisi: soil (Soil Survey, Staff, 1951). penetrates slightly soft - pick points penetrates friable material can be crumbled into individual grains by hand.

Fracture spacing: (Ellen et al.f 1972) cm ID fracture soacino 0-1 0-1/2 v. close

1-5 1/2-2 close 5-30 2-12 moderate 30-1 OO 12-36 wide

>100 >36 v. wide % * PfftCfNT SAND V\ feathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: Standard Munsell color names are given for discoloration the dominant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of samples structure is preserved. SP - Standard Penetration 1 + 3/8 in in ID sampler) S - Thin wall push sampler Relative density of sand and consistency of clay is 0 - Ostorberg fixed-piston sampler correlated with penetration resistance: (Terzaghi and P - Pitcher Barrel sampler Peck, 1948} CH - California Penetration (2 in ID sampler) DC - Diamond Core

relative blows/ft. density blows/ft. consistency

0-4 v. loose <2 v. soft 4-10 loose 2-4 soft

10-30 medium 4-8 medium

30-5O dense 8-15 stiff

>50 v. dense 15-30 v. stiff

>30 hard

Figure 24. Explanation of geologic log.

50 SITE: GILROY *2 EPRI 2 DATE: 10/16/91 BLOWS/ GRAPHIC ^ SAMPLE I « FOOT TYPE LOG £ 1 DESCRIPTION oj -0 SANDY LOAM, dk. yellowish brown (HOLOCENE ALLLUVIUM)

- dk. gray to dk. grayish brown !!i8B

".' !-".-'.v-'.'A: ; ; -i':'.:

'". »' _' ."/>",. »'-«9 - 5 GRAVELLY SAND

rinr-jrjr. SILTY CLAY LOAM, dk. grayish brown to brown ^r=r=nr=^ z"ir"-T"ir'ir"i

ii-£i HHEi- LOAMY SAND, brown, medium to coarse grained -10 ffiij&'J - SANDY FINE GRAVEL :8*91*%-?>Av»

?v>T%2r.-/> .iXKlSLY _ CLAY, pale brown, v. stiff (LATE PLEISTOCENE ALLUVIUM)

-1i \j5

SANDY FINE GRAVEL, brown, mostly graywacke fragments

P&5Mx JtS&W. Pp$ -20 ^^'^

* ^ "^ CLAY, yellowish brown (PLEISTOCENE LAKE DEPOSITS) dk. greenish gray, v. stiff -JjT ^s*"S^^

-25

: ^^^^ \j\jon

Figure 25. Geologic log for Gilroy #2 (EPRI #2).

SITE: GILROY #2 EPRI 2 DATE SAMPE BLOWS FOOT TYPE GRAPH LOG Si 5 DESCRIPTION 0 E 60-

GRAVEL

GRAVELLY SAND, yellowish brown 65 GRAVEL

ft"?.*:*.*'

-70 GRAVELLY SAND

GRAVEL

SANDY __.. GRAVEL gfrg>;.tt|-7 5 GRAVELLY SANDY CLAY LOAM, olive grown, v. poorly sorted

-80

GRAVEL

Figure 25. (Continued). 53 SITE: GILROY ^2 EPRI 2 DATE SAMPLE GRAPHIC BLOWS FOOT TYPE LOG DESCRIPTION

90- GRAVEL, dk. yellowish brown, v. poorly sorted, texture of matrix is SANDY CLAY LOAM

GRAVEL SANDY CLAY LOAM

it-100

-105

GRAVEL - SANDY CLAY LOAM, v. dense, v. pjoorly sorted GRAVEL I

110 GRAVEL

.' t.' .' "" GRAVEL

- GRAVEL

120

Figure 25. (Continued). 54 SITE: GILROY #2 EPRI 2 DATE: «-» BLOWS/ SAMPLE GRAPHIC FOOT TYPE LOG 2S 0S^J J DESCRIPTION 120 ...,.,__, ;.':ft.. ' ! /. ;; < GRAVELLY SANDY CLAY LOAM, brown, v. dense

. f ^Sf- *L/. ?'v'r:Pfe :tf-)';.*.'-.:.' *.."* '. . .".* <.' . &.&." ' ' . !/ *....v ; -.. p... . -1 P*5 'f&itt, yg-ViY v;^'' 1;-.'.?!-

"'.l*'& .* .' . ..;;;i«f'V^v : :-y<»;';v'

'.'M..'. '!'.; .. .'. . i-'.--fl--.-^J V^'iV»'v ^ ^ ^ -130 *&& mw& .v^V:\V; '.: '.^JJSij;a.-woftw %Rfe rfe^ -135 *^fe, _ GRAVEL ^^ifr.:-»-^:: ^r^g ^v;.;/;- ^'' :V

:/» - r- "41 e^fe -140 ^fes »v^:>:-^: : '»: . . ;:.' >" . ».:-:.'ii .'^i ^^? :.:wja?-.:' r'!.v.\'5tt.v! «: .>: > ;' .' . -145 j^^ :ife;.y/tf.^^-;-yJ ;-;y TI.".;;I :^.W' [feTOJi!1 ? ,';.'.';'.'.'.'.'.',.' 1 ^n

Figure 25. (Continued). 55 SITE: GILROY #2 EPRI 2 DATE: BLOWS/ SAMPLE GRAPHIC FOOT z * TYPE LOG 1 1 DESCRIPTION

1 SO *' tV" f'*fl' ' i':':'.'O""-.< fr/i?-'-'". H';V.'.':'''d.'i'

t*^37*W K'.'fffti-;

?/ #.- --''A'' -155 .".:^*". ' I'"-'.1 ""*' ^ ." * . ' w'- '.* . . - . * '* " -tr * v

^^TTT -':. .' ?.*' *. tf " " *'*'rfl ' " -:.-". IT-. .£ :^ :j

."!ryf";'; 'V-* " .".*vr* .** A1 DUp n ' * ' '"*« " * *-"- * * *' . -^:» " ' -"-I " ' * 'r ' . - "O" - y.-,';-.;y,.;i-.'f. ?S% :T^^

"-' "*" ill -"-* '!'' . .".' ' -165 .' '.'.' '.'V.'tf-:^

- SILTSTONE, brown, deeply weathei ed, (MONTEREY SHALE) v. close to close fractut e spacing

-170

-175

~ i -180

Figure 25. (Continued). 56 SITE: GILROY #2 EPRI 2 DATE: £" .* : £o oo ui DESCRIPTION u. O E CD -180

~ SERPENTINITE, v. dk. greenish gray, sheared, texture is SANDY CLAY Some hard, closely fractured blocks

-185

190

_ SHALE, gray, sheared to v. closely fractured

195

200

205

210

Figure 25. (Continued).

57 SITE: QILROY #2 EPRI 2 DATE: Ul £ I «

£0 ^a* " I ^£g O is-CL *-« oo 2 >. I < j Jui « -i u. DESCRIPTION 00 S °3 210

215 SHALE, black, closely to v. closely fractured

220

H225

230

'235

Figure 25. (Continued). 58 WATER STORAGE TANK WELL PUMP

STOCKPILE

FIELD

WELL PUMP WATER STORAGE TANK

G O ^STOCKPILE **vww BUILDING (ADJOINING PROPERTY) MOTEL ROOMS

LANDSCAPING

PAVEMENT

OFFICE FILTER HOUSE COMG INSTRUMENT

NONTEREY STREET

Protect No. EPRI Field Exploration 90C0586A SITE PLAN Woodward-Clyde Consultants GILOROY NO. 2

Figuxe26. Detailed map showing location of Gilroy #2 (USGS) relative to strong- motion instrument. 59 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY

Monterey Late Pleistocene

serpentmite Qreek ,***?

GILROY #2

Holocene alluvium *<&>,' y

Franciscan sandstone

16Q Franciscan greenstone.. - --od

SCALE 1:24000 o 1 MILE

1000 1000 2000 3000 4000 5000 6000 7000 FEET I i I ' I I I I C 1 KILOMETER

PRELIMINIIT CtOlOCIC MP «F TIE CRITTENDEN QMDMN6LE, SINTI CUM, SINTI CRUZ IND SIN ICNITO COONTICS. C«LIFOIIII - BV Thomas W.^Dibbl**. Jr. and Ecrt E. Brabb isn

Figure2 7. Site location map for Gilroy #2 (USGS).

60 1Definitions of terms used for descriptions of sedimentary deposits ar d bedrock materials

Rock hardness: response to hand and geologic Texture: the relative proportions of clay, silt, and hammer: (Bten et al.. 1972) sand belo w 2mm. Proportions of larger particles are indicated by modifiers of textural class names, hard - hammer bounces off with solid sound Determin ation is made in the field mainly by feeling firm - hammer dents with thud, pick point dents or the moistt soil (Soil Survey, Staff, 1951). penetrates slightly soft - pick points penetrates tOO* friable material can be crumbled into individual grains by hand.

TO/ J? Fracture spacing: (Ellen et al., 1972) 7 CLAY \ cm in fracture spacing */' AT /A W ^> 0-1 0-1/2 v close " / \ /SILTY\ ' » / / \ / CL *V \ o 4 1-5 1/2-2 close I I»L * T \ \ »v\ J \ CLAY LOAM V LOAM \«P 5-30 2-12 moderate r LOAM c / V \ LOAM / \ 30-100 12-36 wide \ /SILT LOAM _ \ o XN .SANDY UOAM\ ____ / / \ /Ni.OAM1 >100 >36 V wide /SAND\SA «R . j . . y v % * * i>i* ttit PEKCINT iAND Weathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: S tandard Munsell color names are given for discoloration the dom inant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of samples structure is preserved. SP - Star idard Penetration 1 + 3/8 in in ID sampler) S - Thin- wall push sampler Relative density of sand and consistency of clay is 0 - Oste rberg fixed-piston sampler correlated with penetration resistance: (Terzaghi and P - Pitch er Barrel sampler Peck. 1948) CH - Cali fornia Penetration (2 in ID sampler) DC - Oiainond Core

relative blows/ft. density blows/ft. consistencv

O-4 v. loose <2 v. soft 4-10 loose 2-4 soft 10-30 medium 4-8 medium 30-50 dense 8-15 stiff

>50 v. dense 15-30 v. stiff

>30 hard

Figure 28. Explanation of geologic logs.

61 GILROY #2 USGS 9/26/79 SANDY LOAM, dk. brown, mostly fine to medium grained sand, with lenses of coarse sand and gravel.

SANDY GRAVEL, mostly <30 mm 10 SAND, poorly sorted to v. coarse size. SANDY T:LAY and SILT LOAM, yellowish brown mottled It. grey______SANDY FINE GRAVEL, dk. greyish brown, 20 mostly <10 mm, well sorted SILTY CLAY, greyish brown to grey

.30 dk. grey

SILT LOAM, dk. grey FINE SANDY LOAM, yellowish brown SAND, yellowish brown-strong brown 40 SANDY GRAVEL, yellowish brown lenses of coarse sandy clay loam

50 m GRAVELLY SAND 60

Figure 29. Geologic log of Gilroy #2 (USGS) borehole.

62 GILROY USGS 9/26/79 60 SANDY CLAY, yellowish brown SANDY TINE GRAVEL, yellowish brown poor'y sorted to 10 mm.

70 SANDY CLAY, yellowish red poorly sorted with lenses of SANDY GRAVEL

SANDY LAY, yellowish brown 80

Intertedded GRAVELLY COARSE SAND and SANDY CLAY LOAM poorly sorted 100

lense$ of SANDY CLAY, greyish brown

^-120

Figure 29. (Continued).

63 GILROY *2 USGS 9/26/79 120

°5-U'.

130 Interbedded SANDY GRAVEL and SANDY LOAM, poorly sorted

-140

150

160 SANDY CLAY, reddish brown to greyish brown, v. firm, some lenses of sandy loam

-170

grading coarser

180 SANDSTONE, greyish brown to grey, medium to coarse grained

Figure 29. (Continued).

64 S-WAVE Time (milliseconds) Time (milliseconds) 0 500 0 500

2.5 45

10 60

15 70

20 80

a o 0

25 90

30 100

35 110

40 120

Gilroy #2 CUSGS3

Figure 30. Horizontal-component record section from impacts in opposite horizontal directions superimposed for identification of shear arrivals. Two set of picks are shown, S wave onset (solid circles) and first trough (filled). S-wave onset picks are used for velocity determinations. 65 Time (sec) P-WAVE Tjme (sec) 0 0.1 0.2 0.3 0.4 0 0.1 0.2 0.3 0.4 0

5 65

10 70

15 75

20 80

25 85

30 90

45 105

50 110

55 115

60 120

GILROY#2 (USGS)

Figure 31. Vertical-component record section. P-wave arrivals are shown by the solid circles. Intermediate traces at 2.5 meter intervals are excluded for clarity.

66 Time (sec) 0.05 0.1 0.15 0.2 0.25 0.3

50-

co £"5 100-J

CL 0> Q

150-

200

Gilroy (USGS Hole)

Figure 32. Time-depth graph of P-wave and S-wave picks. Line segments show the hinged-least-squares fit to the data points.

67 S Velocity (m/sec) 200 400 600 800

SANDY LOAM IHDLOCENE ALLUVIUM)

SAND H-AT PLEISTOCENE ALLUVIUM)

SANDY CLAY SANDY FINE GRAVEL SILTY CLAY (PLEISTOCENE LAKE DEPOSITS]

GRAVEL 50- SANDY LOAM sat

SANDY CLAY GRAVEL co m ESS SANDY CLAY LOAM 5"S E GRAVEL

100- GRAVELLY SANDY CLAY LOAM GRAVEL QL

Q GRAVEL

150-

Gilroy (USGS Hole)

Figure 33. S-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplifiec I geologic log is shown for correlation with velocities.

68 P Velocity (m/sec) 1000 2000 3000

SANDY LOAM WOLOCENE ALLUVIUM)

GRAVEL SAND 0-ATE PLEISTOCENE ALLUVIUM)

SANDY CLAY . SANDY FINE GRAVEL

SILTY CLAY (PLEISTOCENE LAKE DEPOSITS!

FINE SANDY LOAM (PLEISTOCENE ALLUVIUM)

GRAVEL 50- SANDY LOAM

SANDY CLAY GRAVEL co SANDY CLAY LOAM CD-» o

GRAVEL

100- GRAVELLY SANDY CLAY LOAM if! CL o Q SRAVEL GRAVELLY SANDY CLAY LOAM

150-

Gilroy (USGS Hole) Figure 34. P-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

69 TABLE 5. S-wave arrival times and velocity summaries for Gilroy #2 (USGS).

d(m) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0134 1 -.2 .0 .0 .000 184 178 190 603 585 622 5.0 16.4 .0233 1 .4 2.5 8.2 .014 184 178 190 603 585 622 7.5 24.6 .0320 1 -.2 8.2 26.9 .035 269 261 277 883 857 910 10.0 32.8 .0402 1 .2 15.0 49.2 .055 343 334 354 1127 1094 1161 12.5 41.0 .0469 1 -.4 21.6 70.9 .070 433 418 449 1421 1371 1475 15.0 49.2 .0551 1 .5 30.0 98.4 .101 270 265 275 886 870 902 17.5 57.4 .0601 1 -.3 36.5 119.8 .120 335 326 344 1099 1070 1128 20.0 65.6 .0655 1 -.6 50.0 164.0 .147 509 500 519 1671 1640 1704 22.5 73.8 .0737 1 .5 71.2 233.6 .176 725 708 743 2379 2323 2438 25.0 82.0 .0829 1 .5 95.0 311.7 .221 532 523 543 1747 1714 1780 27.5 90.2 .0910 1 -.7 120.0 393.7 .256 713 694 734 2340 2277 2407 30.0 98.4 .1011 1 .2 32.5 106.6 .1087 1 .3 35.0 114.8 .1153 1 -.6 37.5 123.0 .1224 1 .1 >| 40.0 131.2 .1275 1 .3 o 45-° 147.6 .1371 1 .1 50.0 164.0 .1473 1 .5 Explanation: 55.0 180.4 .1529 1 -.8 60.0 196.9 .1609 1 .3 d(m) = depth in meters 65.0 213.3 .1665 2 -.5 d(ft) = depth in feet 70*v~»~v 0 229.7 .1746 2 .1 75.0 246.1 .1836 2 .2 t(sec) = arrival time in seconds (S-wave arrival times are 80.0 262.5 .1936 2 .5 the average of picks from traces obtained from 85.0 278.9 .2017 2 -.2 90.0 295.3 .2117 2 .2 hammer blows differing in direction by 180°) 95.0 311.7 .2202 2 -.3 sig = sigma, standard deviation normalized to the 100.0 328.1 .2272 2 -.3 105.0 344.5 .2352 2 .2 standard deviation of best picks 110.0 360.9 .2427 2 .4 rsdl/sig = least-squares residual divided by sigma 115.0 377.3 .2488 2 .0 120.0 393.7 .2553 2 -.3 dtb(m) = depth to bottom of layer in meters dtb(ft) = depth to bottom of layer in feet ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

N9N.S 2-20-92 2:39p Page 1 of 1 TABLE 6. P-wave arrival times and velocity summaries for Gilroy #2 (USGS).

d(m) d(ft) t(sec) ..T rsdl/sig Itb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0094 '.6 .0 .0 .000 259 250 268 849 820 880 5.0 16.4 .0148 1 2.5 8.2 .010 259 250 268 849 820 880 7.5 24.6 .0183 1 -.5 8.2 26.9 .020 548 522 577 1798 1712 1894 10.0 32.8 .0215 1 .2 15.0 49.2 .025 1426 1285 1601 4677 4217 5251 12.5 41.0 .0232 1 .1 21.6 70.9 .032 936 844 1051 3072 2771 3448 15.0 49.2 .0247 1 -.1 30.0 98.4 .035 2417 1912 3285 7930 6273 10777 17.5 57.4 .0279 5 .1 36.5 119.8 .039 2019 1702 2482 6624 5583 8143 20.0 65.6 .0301 5 .0 50.0 164.0 .047 1570 1497 1652 5152 4910 5419 22.5 73.8 .0322 2 .0 71.2 233.6 .056 2308 2205 2422 7573 7234 7946 25.0 82.0 .0333 2 .0 95.0 311.7 .068 2031 1959 2109 6663 6426 6918 27.5 90.2 .0344 2 .0 120.0 393.7 .080 2046 1974 2124 6714 6477 6970 30.0 98.4 .0355 2 .1 32.5 106.6 .0366 1 .0 35.0 114.8 .0376 1 -.2 37.5 123.0 .0396 1 .4 40.0 131.2 .0407 1 -.1 45.0 147.6 .0437 1 -.3 50.0 164.0 .0468 1 -.4 Explanation: 55.0 180.4 .0498 1 .5 60.0 196.9 .0518 1 .3 d(m) = depth in meters 65.0 213.3 .0538 1 .1 d(ft) = depth in feet 70.0 229.7 .0559 1 .1 75.0 246.1 .0569 2 -.7 t(sec) = arrival time in seconds (S-wave arrival times are 80.0 262.5 .0609 1 .2 the average of picks from traces obtained from 85.0 278.9 .0629 1 -.3 90.0 295.3 .0649 1 -.7 hammer blows differing in direction by 180°) 95.0 311.7 .0689 2 .4 sig = sigma, standard deviation normalized to the 100.0 328.1 .0709 1 .4 105.0 344.5 .0729 1 -.1 standard deviation of best picks 110.0 360.9 .0759 1 .5 115.0 377.3 .0779 1 .1 rsdl/sig = least-squares residual divided by sigma 120.0 393.7 .0799 1 -.4 dtb(m) = depth to bottom of layer in meters dtb(ft) = depth to bottom of layer in feet ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

N9N.P 2-20-92 2:38p Page 1 of 1 UNITED STATES OAKLAND WEST QUADRANGLE DEPARTMENT OF THE INTERIOR CALIFORNIA GEOLOGICAL SURVEY 7.5 MINUTE SERIES (TOPOGRAPHIC)

OAKLAND OUTER HARBOR WHARF

f.v

SCALE 1:24000 o 1 MILE i " ' ' ' 1000 1000 2000 3000 4000 5000 6000 7000 FEET ' ' ' ' 0 1 KILOMETER

CONTOUR INTERVAL 20 FEET

Figure 35. Site location map for Oakland Outer Harbor Wharf (this is the same as Figure 7). The borehole is within 15 meters of the strong-motion recorder. 72 Definitions of terms used for descriptions of sedimentary deposits and bedrock materials

Rock hardness: response to hand and geologic Texture: the relative proportions of clay, silt, and hammer: (EWenetal.. 1972) sand below 2mm. Proportions of larger particles are indicated by modifiers of textural class names. hard - hammer bounces off with solid sound Determination is made in the field mainly by feeling firm - hammer dents with thud, pick point dents or the moist soil (Soil Survey, Staff, 1951). penetrates slightly soft - pick points penetrates friable material can be crumbled into individual grains by hand.

Fracture spacing: (Ellen et al., 1972) cm in fracture soacino 0-1 0-1/2 v. close

1-5 1/2-2 close

5-30 2-12 moderate 30-100 12-36 wide

>100 >36 v. wide

Weathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: Standard Munsell color names are given for discoloration the dominant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of samples structure is preserved. SP - Standard Penetration 1 +3/8 in in ID sampler) S - Thinfwall push sampler Relative density of sand and consistency of clay is 0 - Osterberg fixed-piston sampler correlated with penetration resistance: (Terzaghi and P - Pitcher Barrel sampler Peck. 1948) CH - California Penetration (2 in ID sampler) DC - Diamond Core

relative blows/ft. density blows/ft. consistency

0-4 v. loose <2 v. soft

4-10 loose 2-4 soft

10-30 medium 4-8 medium

30-50 dense 8-15 stiff

>50 v. dense 15-30 v. stiff

>30 hard

Figure 36. Explanation of geologic logs. SITE: OAKLAND OUTER HARBOR WHARF DATE: 12/10/90 BLOWS/ SAMPLE GRAPHIC FOOT DEPTH (meters) TYPE LOG DESCRIPTION

-0 GRAVELLY SANDY LOAM, brown (ARTIFICIAL FILL)

Sand, olive brown, well sorted, fine to medium grained, loose S 7 W v.dk. greenish gray S s -5

s r - CLAY, v.dk. greenish gray, some shells, v. soft (HOLOCENE BAY MUD) 0 5F "5F"S SAND, olive gray to olive, well sorted (MERRITT SAND) 15 fine to medium grained, medium dense 11 SP 32 SP yellowish brown, medium dense to dense -10 11 SP s LOAMY SAND to FINE SANDY LOAM, yellowish brown 13 ££. 31 W

i:-\ ' " ?." %" -15 s SAND, brown to dk. grayish brown, well sorted, fine grained

'v:'"^:'-''-' ." *"'

SO/ HP : ' ' " ' ' * '. -.I 4* .":'* ". * '.'; ".'."' -20 CLAY, v.dk. greenish gray, stiff (PLEISTOCENE BAY MUD) S SAND, v.dk.greenish gray, well sorted, very fine to fine grained CLAY, v.dk. greenish gray

::-i<-'-:-:'\\".i SAND, v.dk. greenish gray, well sorted, very fine to fine grained

CLAY, v.dk. greenish gray, stiff 31 H »30

Figure 37. Geologic log for Oakland Outer Harbor Wharf. 74 SITE: OAKLAND OUTER HARBOI^ WHARF DATE: BLOWS/ SAMPLE GRAPHIC FOOT DEPTH (meters) TYPE LOG DESCRIPTION

0 W

-35

S Las^H!^ -40 ) r==:.=F==

SAND, v.dk. greenish gray

-4^ *T \J

-50 GRAVELLY SAND, v. dense

CLAY to SANDY CLAY LOAM, v.dk. greenish gray

-55 38SC

f*r\OU --1 -1 ' ' '

Figure 37. (Continued). 75 SITE: OAKLAND OUTER HARBOR WHARF DATE: BLOWS/ SAMPLE GRAPHIC ^ FOOT TYPE LOG J 2 £ 5 DESCRIPTION o 5 p>n i . . _.r-j ~ -:- t/U S

M»

V^/'Svv/ SAND

-65 HI

'' ' '"'. : . ' :. '.j:. 7 Q SAND, fine to medium grained S Ctei^i SILTY CLAY, v.dk. greenish gray, v. stiff

gjtg'v^: SAND

' .:. . ' . : .* SAND

-75

:^V>: "/* " :.' SAND M - CLAY, v.dk. greenish gray, v. stiff

-80 S

^» -85 ^^^P^ ii.-^g_S=|

B^SoS no

Figure 37. (Continued). 76 SITE: OAKLAND OUTER HARBOR WHARF DATE:

UJ 50 ti oo in DESCRIPTION u. c O E OQ 0 90-

SAND, dk. greenish gray, v. fine to fine grained, v. dense

-95

SANDY CLAY LOAM, yellowish brown GRAVEL, pale brown to brown, siliceous shale fragments CLAY, dk. grayish brown, hard 1 00 dk. greenish gray |

" FINE GRAVELLY SANDY LOAM, |brown, v. noorly sorted, 'i ._.., pale brown siliceous shale, dense

l SILTY CLAY, olive gray

LOAMY SAND to SAND, brownish yellow, some fine gravel

115

CLAY, dk. greenish gray, mottled greenish gray

120

Figure 37. (Continued). 77 SITE: OAKLAND OUTER HARBOR WHARF DATE: BLOWS/ SAMPLE GRAPHIC ^ FOOT i S TYPE LOQ £5 DESCRIPTION °S 120 pggjif

.V'-'.v;:'.-'.^ FINE GRAVELLY SAND ^'£v£?R?*;-!:V. SANDY LOAM to SANDY CLAY LOAM, yellowish brown, v. poorly sorted, occasional pebbles

-125

:£:^:yi£S£ -130 P ::V*:i':*:*.--':--:&: Ssfc&s GRAVEL

-135

V-'-;:i:;::?;/':V.'.O;:?fl ^m :.-.:.v;-.;.;V^v;-.vr>-V-'

.;. '.' '.'.' -I :" .' -' -. ' : ' ?'' *' ' ' '?' ' '. '-'.-." "-'. '" -140

P olive

!.';" " ".* :>; ". "''V-* " v : "» "* '. *.* ."" -145 '.* b * *.'. GRAVELLY SAND .& v«V fc

**. ii:*>>. ;':<". >>:: .-. SANDY LOAM

- -150

Figure 37. (Continued). 78 SITE: OAKLAND OUTER HARBOI^ WHARF DATE: BLOWS/ SAMPLE GRAPHIC FOOT DEPTH (meters) TYPE LOG DESCRIPTION

1 Oc fr» ' ' SHALE, dk. grayish brown, mbderatley weathered (FRANCISCAN ASSEMBLAGE) » black, fresh

V.V.V, ^8§ -155 SANDSTONE, dk. gray, hard, some black SHALE IvX'X*

'®mmmam xxm -160 .V.V.V.V i >*:*x*: >:*:*:*:.... . *

>:*: :*:* :*:*: :*: -165

*: :*:*:' DC

-170

-175

-180

Figure 37. (Continued). 79 S-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 0.4 0 0.1 0.2 0.3 0.4 0.5 o 5 -«^y]fr>ft^^ 85 ^^^^^ 10 90 '^^^^^ 15 > V Vv 95 ^~<*^^^ 20 ^fao^^ 100 ^^^tx?-^^ 25 105 30 110 ^AK^^ 35 ^-^^^^ 40 f £ 120 45 (§"125 0 50 **>-^<}($^^ \sJ 130 ^^^^^^ 55 135 ^*~&^^^^ 60 A >^^^^^^^^ 65 <=*'"*>sw~x^/^^ 140 70 145 ^^^^^ 75 j&ZSbsSr****^^ 150 vxv 80 ">>y^^^ 155 ^^«^^^^ 160

Outer Harbor Wharf

Figure 38. Horizontal-component record section from impacts in opposite horizontal directions superimposed for identification of shear arrivals. S-wave arrivals are shown by the accent marks.

80 P-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 0.4 0 0.1 0.2 0.3 0.4

85 - lAv*w>*~N/w* o^^\/\/^A/WA«A~^>^v ^^x 90 ^Jys^/\^-v^^-^Wyy^^\^^ 95 100 105 110 - T^WJ *~~ V^\A/W(yN/VN^Vs/^

120 o_ ^ 0 Q 130 135 140 145 150 155 160

Outer Harbor Wharf

Figure 39. Vertical-component record section. P-wave arrivals are shown by the solid circles.

81 Time (sec) 0.1 0.2 0.3 0.4 0.5 I

50-

(0 "55JD E

150-

Outer Harbor Wharf Figure 40. Time-depth graph of P-wave and S-wave picks. Line segments show the hinged-least-squares fit to the data points.

82 S Velocity (m/sec) 200 400 600 800

GRAVELLY SANDY LOAM (ARTIFICIAL FILL) I SAND IHBLOCENE BAY MUOi (MERRITT SAND)

£21 ci (PLEISTOCENE BAY MUD)

50-

co 5"S E

SAND 100- SANDY CLAY LQATCT

FINE GRAVELLY SANDY LOAM

LOAMY SAND TO SAND

SANDY LOAM to SANDY CLAY LOAM

150- GRAVELLY SAND (FRANCISCAN ASSEMBLAGE) weathered SANDSTONE, fresh

Oakland Outer Harbor Wharf

Figure 41. S-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

83 P Velocity (m/sec) 500 1000 1500 2000 2500

GRAVELLY SANDY LOAM (ARTIFICIAL FILL) SAND IHOLQCENE BAY MUDI (MERRITT SAND)

(PLEISTOCENE BAY MUD)

SAND CLAY

50-

100- SANDY CLAY LOAM FINE GRAVELLY SANDY LOAM

LOAMY SAND TO SAND

SANDY LOAM to SANDY CLAY LOAM

150- GRAVELLY SAND SHALE, (FRANCISCAN ASSEMBLAGE) moderately weathered & SANDSTONE, fresh

Oakland Outer Harbor Wharf

Figure 42. P-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

84 TABLE 7. S-wave arrival times and velocity summaries for Oakland Outer Harbor Wharf.

dCm) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vlOn/s) vu(m/s) v(ft/s) vt(ft/s) vu(ft/s) 2.5 8.2 .0129 1 J .0 .0 .000 198 190 207 650 622 680 5.0 16.4 .0251 -.1 5.0 16.4 .025 198 190 207 650 622 680 7.5 24.6 .0395 -.4 6.7 22.0 .037 147 127 173 482 418 569 10.0 32.8 .0501 .7 12.5 41.0 .059 263 242 287 862 795 943 12.5 41.0 .0585 -.4 20.0 65.6 .079 367 345 392 1203 1131 1286 15.0 49.2 .0650 -.7 40.0 131.2 .162 242 238 246 795 782 808 17.5 57.4 .0740 1.5 50.0 164.0 .199 271 262 280 888 860 918 20.0 65.6 .0795 .2 91.5 300.2 .330 316 314 319 1038 1029 1047 22.5 73.8 .0888 -.9 121.5 398.6 .393 475 465 484 1557 1527 1589 25.0 82.0 .0995 -.5 131.5 431.4 .422 345 321 372 1132 1055 1220 27.5 90.2 .1112 .9 155.0 508.5 .453 771 698 860 2529 2291 2823 30.0 98.4 .1194 -1.2 35.0 114.8 .1421 .9 40.0 131.2 .1617 -.2 45.0 147.6 .1804 .0 50.0 164.0 .1995 .7 55.0 180.4 .2131 -1.5 00 60.0 196.9 .2292 -1.2 S 65.0 213.3 .2483 2.1 w 70.0 229.7 .2618 -.2 Explanation: 75.0 246.1 .2789 1.1 d(m) = depth in meters 80.0 262.5 .2934 -.2 85.0 278.9 .3100 .6 d(ft) = depth in feet 90.0 295.3 .3230 -2.2 t( g**\r-\ *» »» mral tim/* in Of*/* fin ft a ( ^_Ufai/4> tti»i*iiral iiTnf*a &ff* 95.0 311.7 .3400 2.7 111 oCC 1 35 cfcfriVcU wili It? ift CK?V»UI i us t»j*w<>vc ojttivoi miico cm? 100.0 328.1 .3461 -1.8 the average of picks from traces obtained from 105.0 344.5 .3566 2 -.9 110.0 360.9 .3701 1 1.2 hammer blows differing in direction by 180°) 115.0 377.3 .3781 1 -1.4 sig = sigma, standard deviation normalized to the 120.0 393.7 .3902 1 .2 125.0 410.1 .4067 2 1.7 standard deviation of best picks 130.0 426.5 .4182 2 .2 rsdl/sig = least-squares residual divided by sigma 135.0 442.9 .4267 2 .0 140.0 459.3 .4327 2 -.2 dtb(m) = depth to bottom of layer in meters 145.0 475.7 .4367 2 -1.5 dtb(fb) = depth to bottom of layer in feet 150.0 492.1 .4468 3 .2 155.0 508.5 .4543 2 .8 ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

ONU.S 2-20-92 2:41p Page 1 of 1 TABLE 8. P-wave arrival times and velocity summaries for Oakland Outer Harbor Wharf.

d(m) d(ft> t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2. 5 8 .2 .0058 1 .0 .0 .0 .000 431 398 470 1414 1307 1541 5. 0 16 .4 .0092 1 -.1 2.5 8.2 .006 431 398 470 1414 1307 1541 7. 5 24 .6 .0108 1 .3 5.0 16.4 .009 713 607 866 2341 1990 2842 10. 0 32 .8 .0116 1 -.2 12.5 41.0 .013 2010 1738 2382 6594 5703 7816 12. 5 41 .0 .0130 1 .0 20.0 65.6 .017 1867 1670 2116 6124 5478 6943 15. 0 49 .2 .0142 1 -.2 40.0 131.2 .030 1546 1488 1608 5072 4884 5277 17. 5 57 .4 .0163 1 .6 50.0 164.0 .036 1716 1592 1861 5631 5224 6106 20. 0 65 .6 .0175 1 .4 91.5 300.2 .061 1680 1651 1709 5510 5417 5606 22. 5 73 .8 .0185 1 -.2 121.5 398.6 .076 1888 1836 1943 6196 6025 6376 25. 0 82 .0 .0196 1 -.7 131.5 431.4 .082 1741 1601 1908 5712 5251 6261 27. 5 90 .2 .0216 1 -.3 155.0 508.5 .094 1976 1885 2077 6484 6183 6815 30. 0 98 .4 .0237 1 .2 35. 0 114 .8 .0267 1 -.1 40. 0 131 .2 .0298 1 -.2 45. 0 147 .6 .0338 1 .9 50. 0 164 .0 .0358 1 .0 55. 0 180 .4 .0388 1 .0 00 60. 0 196 .9 .0419 1 .1 £ 65- 0 213 .3 .0449 1 .2 w 70. 0 229 .7 .0469 1 -.8 Explanation: 75. 0 246 .1 .0499 1 -.8 80. 0 262 .5 .0539 1 .2 d(m) = depth in meters 85. 0 278 .9 .0569 1 .2 d(ft) = depth in feet 90. 0 295 .3 .0599 1 .3 95. 0 311 .7 .0629 1 .5 t(sec) = arrival time in seconds (S-wave arrival times are 100. 0 328 .1 .0649 1 -.1 the average of picks from traces obtained from 105. 0 344 .5 .0669 1 -.8 110. 0 360 .9 .0709 1 .6 hammer blows differing in direction by 180°) 115. 0 377.3 .0729 1 -.1 sig = sigma, standard deviation normalized to the 120. 0 393 .7 .0759 1 .3 125. 0 410 .1 .0779 1 -.5 standard deviation of best picks 130. ooo 426.5 .0819 1 .6 rsdl/sig = least-squares residual divided by sigma 135. 442.9 .0839 1 .0 140. 459.3 .0859 1 -.6 dtb(m) = depth to bottom of layer in meters 145. ooo 475 .7 .0889 1 -.1 dtb(ft) = depth to bottom of layer in feet 150. 492 .1 .0919 1 .4 155. 508 .5 .0940 1 .0 ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

OHW.P 2-20-92 2:40p Pag* 1 of 1 UNITED STATES MONTARA MOUNTAIN QUADRANGLE DEPARTMENT OF THE INTERIOR CALIFORNIA-SAN MATEO CO. GEOLOGICAL SURVEY 7.5 MINUTE SERIES (TOPOGRAPHIC)

FRANCISCO INTERNATIONAL AIRPORT

FRAN

INIERNATIONAT AIRP

SCALE 1:24000 1 MILE

1000 0 1000 2000 3000 4000 5000 6000 7000 FEET t i i i t i i i i i ~

1 KILOMETER

Figure 43. Location map for San Francisco International Airport. The borehole is located within 15 meters of the strong-motion recorder.

87 definitions of terms used for descriptions of sedimentary deposits and bedrock materials

Rock hardness: response to hand and geologic Texture: the relative proportions of clay, silt, and hammer; (Ellen etal., 1972) sand below 2mm. Proportions of larger particles are indicated by modifiers of textural class names. hard - hammer bounces off with solid sound Determination is made in the field mainly by feeling firm - hammer dents with thud, pick point dents or the moist soil (Soil Survey, Staff, 1951). penetrates slightly soft - pick points penetrates friable material can be crumbled into individual grains by hand.

Fracture spacing: (Ellen et at., 1972) cm In fracture soacino 0-1 0-1/2 v. close

1-5 1/2-2 close

5-30 2-12 moderate

30-1 OO 12-36 wide

>100 >36 v. wide

Weathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: Standard Munsell color names are given for discoloration the domiinant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of samples structure is preserved. SP - Staridard Penetration 1 + 3/8 in in ID sampler) S - Thin-wall push sampler Relative density of sand and consistency of clay is 0 - Osterberg fixed-piston sampler correlated with penetration resistance: (Terzaghi and P - Pitcher Barrel sampler Peck, 1948) CH - California Penetration (2 in ID sampler) DC - Diamond Core

relative blows/ft. density blows/ft. consistencv

0-4 v. loose <2 v. soft

4-10 loose 2-4 soft

10-30 medium 4-8 medium

30-50 dense 8-15 stiff

>50 v. dense 15-30 v. stiff >30 hard

Figure 44. Explanation of geologic log.

88 SITE: S.F.INTERNATIONAL AIRPORT DATE: 2/21/91 SAMPLE GRAPHIC BLOWS FOOT TYPE LOG DESCRIPTION o .,....._.... SANDY CLAY LOAM, mottled dk. grayish brown and olive, poorly sorted SJL ^::^£ ~ occasional pebbles 5E ££££?; - FINE SANDY CLAY LOAM, v.dk. greenish gray I] _ SILTY CLAY, black, stiff (HOLOCENE BAY MUD) O EI-EJ ri.-i.-: _ H~-^KE v.dk. greenish gray, soft S II'll S_E===Bi:=i-5 S^ s S iiill:" V.FINE SANDY LOAM to LOAM, olive to pale olive IT s^ s 1 0 LOAMY SAND, v.dk. grayish brown, moderately well sorted

SAND, v.dk. greenish gray, well sorted, v.fine to fine grained SE

ZTT L SILTY CLAY« Greenish gray, v. stiff (PLEISTOCENE BAY MUD)

S -^^

V.FINE SANDY CLAY LOAM, greenish gray (COLMA FORMATION?) o :::*«* V.FINE SANDY LOAM, olive gray O v&&&:'-/i -20 r * SANDY LOAM GRAVELLY SAND S ill!!? - SILTY CLAY LOAM, dk. greenish gray

SAND S _iiiili-25 SAND

SAND c"i - » : LOAM, v.dk. greenish gray & _ jfeS&viV/^i "

LOAMY SAND, olive gray, poorly sorted to v.coarse size 30

Figure 45. Geologic log for San Francisco International Airport.

89 SITE: S.F. INTERNATIONAL lRPORT DATE SAMPLE BLOWS FOOT TYPE GRAPH G LO Si DESCRIPTION

p - SIBI? ~ V.FINE SANDY LOAM, v.dk. greenish gray

V:^« ^

SAND, yellowish brown

FINE GRAVELLY SAND

_ _ | CLAY, pale olive, v. stiff P ::.:>:--::v::f- 40 V. FINE LOAMY SAND, grayish brown

SAND

LOAM, olive, sand is v.fine dk. greenish gray

:,.,,-^,.|~45 p - n^IL

" "" SILTY CLAY, dk. greenish gray

-50 LOAM» dk- 9reenish gray, sanld is v.fine

-^^!«:

SAND, It. yellowish brown (COLMA FORMATION)

FINE GRAVEL LOAMY FINE SAND to V.FINE SANDY CLAY LOAM, It. yellowish brown, v.dense

Figure 45. (Continued). 90 S!TE: S.IF. INTERNATIONAL AIRPORT DATE: BLOWS/ SAMPLE GRAPHIC ^* FOOT x £ TYPE LOG S; 5 DESCRIPTION °!

fiO ' i ' ? ;' } './' t)L) -- ' P ; .' '/ ; ' ': ^ ' ' . / vV

££':v£.VA* v;v::v.: ;Vv:

-65 %'/A?/:|'-'.V:

FINE SANDY CLAY LOAM, yellowish brown, paleo sol? Bill SANDY LOAM, strong brown, sand to medium size

P &%$$&£ -70

-75

'?A""!.Vi':v:v'-v.v''-": ^ :ft'::'tt'i'"'-:':'-::-:::

^v:@'^^ yellowish brown P _onou ^ iVv-^^-i^X-'V/ - FINE GRAVELLY SAND, yellowish brown, v.dense £$:££

- :K:i:-S'i:

0 _ FINE SANDY LOAM, yellowish brown -85

.;i:-''V:^' ;; . . .;;:;'-: <£ : ; V'. '. i'S'' _ SAND, dk. yellowish brown, well sorted, v.fine to medium grained, v.dense (?Cs":7iSV}

>v^^- noo \j

Figure 45. (Continued). 91 SITE: S.F. INTERNATIONAL AIRPORT DATE; UJ i 2 £0 oo DESCRIPTION 0 6 CO o 90-

1-95

SANDY LOAM, yellowish brown

SAND, strong brown, well sorted, v.fine to medium grained, v.dense

100

M10

brownish yellow

...... -115

120

Figure 45. (Continued). 92 SITE: S.F. INTERNATIONAL AIRPORT DATE: BLOWS/ SAMPLE GRAPHIC ^ FOOT I * TYPE LOG £ 2 DESCRIPTION Qj 120 .ti^i^lVs" KC':iVl*V.\;

!^>£yj::V:; -125 &$&

%;':/&&':

-130

'" '. *.V "?; " *. ." . . .". ' '. ..' ;: . ;/; .'

:V--.:.v.:.v.;: MUDSTONE, v.dk. greenish gray, soft (MERCED FORMATION) -135

-140 P i _ .- »

-145

-150

Figure 45. (Continued). 93 SITE: S.F. INTERNATIONAL AIRPORT DATE: BLOWS/ SAMPLE GRAPHIC *-*, FOOT TYPE LOG H 2 S 1 DESCRIPTION 0 3

1 SO ilii SANDSTONE, It. gray to medium gray, (FRANCISCAN ASSEMBLAGE) $888 fresh, hard si*;:;*;: : : : : : : 8888 mm8888 -155

-160

-165

-170

-175

-180

Figure 45. (Continued). 94 S-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 0.1 0.2 0.3 0.4

°?<*--~^

Q_ CD Q

San Francisco Airport

Figure 46. Horizontal-component record section from impacts in opposite horizontal directions superimposed for identification of shear arrivals. S-wave arrivals are shown by the accent marks.

95 P-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 0.1 0.2 0.3 0.4

-SjIWfy^^

Q_ ^ O

San Francisco Airport

Figure 47. Vertical-component record section. P-wave arrivals are shown by the solid circles.

96 Time (sec) 0.1 0.2 0.3 0.4 0.5

50-

«to »

150-

San Francisco Airport

Figure 48. Time-depth graph of P-wave and S-wave picks. Line segments show the hinged-least-squares fit to the data points.

97 S Velocity (m/sec) 200 400 600 800

SANDY CLAY LOAM (ARTIFICIAL FILL) SILTY CLAY (HOLOCENE BAY MUD)

V. FINE SANDY LDAM TO LOAM SAND

SILTY CLAY (PLEISTOCENE BAY MUD) V. FINE SANDY LOAM (COLMA FORMATION?)

SAND

LOAM 50- SILTY CLAY LDAM (CDLMA FORMATION) co FINE SANDY CLAY LOAM "SJD SANDY LDAM E FINE GRAVELLY SAND

FINE SANDY LOAM CL SAND (D Q SANDY LDAM 100- SAND

(MERCED FORMATION)

150- Jiggi; SANDSTONE (FRANCISCAN ASSEMBLAGE)

San Francisco Airport

Figure 49. S-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

98 P Velocity (m/sec) 500 1000 1500 2000 2500

f~*f SANDY CLAY LOAM (ARTIFICIAL TILL) gg: SILTY CLAY (HOLDCENE BAY MUD)

V. FINE SANDY LOAM TO LOAM ^i' 'SAND

pH^i SILTY CLAY (PLEISTOCENE BAY MUD) V. FINE SANDY LOAM (COLMA FORMATION?!

#£: SAND

%.%. SAND

' LOAM 50- LOAM 3&g; SAND (COLMA FORMATION) co DAM "S£ SANDY LOAM E _;:.. FINE GRAVELLY SAND

FINE SANDY LOAM Q. ::|| _SAND

MUDSTONE (MERCED FORMATION)

150- X SANDSTONE (FRANCISCAN ASSEMBLAGE) :i :

San Francisco Airport

Figure 50. P-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

99 TABLE 9. S-wave arrival times and velocity summaries for San Francisco International Airport.

d(m) d(ft) t(sec) sfg rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0082 1 -.2 .0 .0 .000 298 271 330 977 889 1084 5.0 16.4 .0336 1 .5 2.5 8.2 .008 298 271 330 977 889 1084 7.5 24.6 .0508 1 -1.4 6.5 21.3 .048 101 98 105 332 322 343 10.0 32.8 .0644 1.5 14.0 45.9 .080 233 225 242 766 739 794 12.5 41.0 .0738 .2 22.5 73.8 .111 272 264 281 893 867 921 15.0 49.2 .0835 -.2 35.0 114.8 .148 341 333 349 1119 1093 1145 17.5 57.4 .0923 -.6 65.0 213.3 .220 417 412 422 1368 1352 1384 20.0 65.6 .1014 -.7 87.2 286.1 .258 576 565 588 1890 1852 1930 22.5 73.8 .1113 .1 115.0 377.3 .308 564 554 573 1849 1818 1881 25.0 82.0 .1182 -.4 133.2 437.0 .337 614 595 635 2015 1953 2082 27.5 90.2 .1269 1.0 145.0 475.7 .355 682 641 730 2239 2102 2395 30.0 98.4 .1341 .9 35.0 114.8 .1475 -.4 40.0 131.2 .1588 -1.1 45.0 147.6 .1719 .0 _». 50.0 164.0 .1836 -.3 0 55.0 180.4 .1972 1.3 2 ^.0 196.9 .2088 .9 0 65.0 213.3 .2189 -1.0 Explanation: 70.0 229.7 .2284 -.1 75.0 246.1 .2365 -.7 d(m) = depth in meters 80.0 262.5 .2460 .1 d(ft) = depth in feet 1.0 90.0 295.3 .2631 -.3 t(sec) = arrival time in seconds (S-wave arrival times are 95.0 311.7 .2721 -.1 the average of picks from traces obtained from 100.0 328.1 .2801 -1.0 105.0 344.5 .2907 .7 hammer blows differing in direction by 180°) 110.0 360.9 .2987 -.1 sig = sigma, standard deviation normalized to the 115.0 377.3 .3087 1.0 120.0 393.7 .3147 -1.2 standard deviation of best picks 125.0 410.1 .3242 .2 rsdl/sig = least-squares residual divided by sigma 130.0 426.5 .3318 -.3 135.0 442.9 .3408 .8 dtb(m) = depth to bottom of layer in meters 140.0 459.3 .3468 -.5 dtb(ft) = depth to bottom of layer in feet 145.0 475.7 .3548 .2 ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

8F0.8 2-20-92 2:43p Page 1 of 1 TABLE 10. P-wave arrival times and velocity summaries for San Francisco Interna- tional Airport.

d(m) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0036 u 0 .0 .0 .000 692 623 777 2269 2044 2551 5.0 16.4 .0064 m 0 2.5 8.2 .004 692 623 777 2269 2044 2551 7.5 24.6 .0083 -, 4 6.5 21.3 .008 910 802 1052 2985 2630 3450 10.0 32.8 .0107 m 4 14.0 45.9 .013 1557 1396 1760 5108 4581 5773 12.5 41.0 .0121 m 2 22.5 73.8 .017 1901 1725 2117 6238 5661 6945 15.0 49.2 .0133 -. 1 35.0 114.8 .024 1958 1840 2091 6423 6038 6862 17.5 57.4 .0144 -. 3 65.0 213.3 .041 1725 1686 1765 5658 5530 5792 20.0 65.6 .0155 - m 5 87.2 286.1 .053 1905 1844 1969 6249 6050 6461 22.5 73.8 .0176 m 3 115.0 377.3 .068 1831 1783 1881 6007 5851 6172 25.0 82.0 .0186 m 0 133.2 437.0 .077 1900 1814 1995 6235 5952 6546 27.5 90.2 .0197 1 2 145.0 475.7 .084 1875 1727 2052 6153 5665 6732 30.0 98.4 .0217 i 6 35.0 114.8 .0238 1 1 40.0 131.2 .0258 1 8 45.0 147.6 .0298 1 3 50.0 164.0 .0328 1 4 -L 55.0 180.4 .0349 i 4 O 60.0 196.9 .0379 1 3 _i 65.0 213.3 .0409 1 2 Explanation: 70.0 229.7 .0439 1 2 d(m) = depth in meters 75.0 246.1 .0469 1 6 80.0 262.5 .0489 1 1 d(fb) = depth in feet 85.0 278.9 .0519 1 3 90.0 295.3 .0539 1 4 t(sec) = arrival time in seconds (S-wave arrival times are 95.0 311.7 .0569 1 1 the average of picks from traces obtained from 100.0 328.1 .0599 1 2 105.0 344.5 .0619 1 6 hammer blows differing in direction by 180°) 110.0 360.9 .0649 1 3 sig = sigma, standard deviation normalized to the 115.0 377.3 .0679 i 0 120.0 393.7 .0709 1 4 standard deviation of best picks 125.0 410.1 .0739 i 7 rsdl/sig = least-squares residual divided by sigma 130.0 426.5 .0759 1 1 135.0 442.9 .0779 1 6 dtb(m) = depth to bottom of layer in meters 140.0 459.3 .0809 i 2 dtb(fb) = depth to bottom of layer in feet 145.0 475.7 .0840 1 2 ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

SFO.P 2-20-92 2:42p Page 1 of 1 UNITED STATES OAKLAND WEST QUADRANGLE DEPARTMENT OF THE INTERIOR CALIFORNIA GEOLOGICAL SURVEY 7.5 MINUTE SERIES (TOPOGRAPHIC)

C **» «*t*-;g!S ^~^ x ^^r / 47.^..

SCALE 1:24000 o 1 MILE

1000 1000 2000 3000 4000 5000 6000 7000 FEET

1 KILOMETER

CONTOUR INTERVAL 20 FEET

Figure 51. Site location map for Treasure Island and Yerba Buena Island. For Treasure Island, the borehole is located within 15 meters of the strong-motion recorder. 102 Definitions of terms used for descriptions of sedimentary deposits and bedrock materials

Rock hardness: response to hand and geologic Texture: the relative proportions of clay, silt, and hammer: (Elten et a!., 1972) sand below 2mm. Proportions of larger particles are indicated by modifiers of textural class names. hard - hammer bounces off with solid sound Determination is made in the field mainly by feeling firm - hammer dents with thud, pick point dents or the moist soil (Soil Survey, Staff, 1951). penetrates slightly soft - pick points penetrates friable material can be crumbled into individual grains by hand.

Fracture spacing: (Ellen et al., 1972) cm in fracture soacina ^ 0-1/2 v. close 1-5 1/2-2 close

5-30 2-12 moderate

30-100 12-36 wide

>100 >36 v. wide

Weathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: Standard Munsell color names are given for discoloration the dominant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of samples structure is preserved. SP - Standard Penetration 1 + 3/8 in in ID sampler) S - Thin-wall push sampler Relative density of sand and consistency of clay is 0 - Osterberg fixed-piston sampler correlated with penetration resistance: (Terzaghi and P - Pitcher Barrel sampler Peck. 1948} CH - California Penetration (2 in ID sampler) DC - Diamond Core

relative blows/ft. density blows/ft. consistency

0-4 v. loose <2 v. soft

4-10 loose 2-4 soft

10-30 medium 4-8 medium

30-50 dense 8-15 stiff

>50 v. dense 15-30 v. stiff >30 hard

Figure 52. Explanation of geologic log.

103 SITE: TREASURE ISLAND DATE: 11/19/90 til >UJ Jo £0 Q. * 00 oc«2 -1 in ® DESCRIPTION -j u. O 6 m o

° GRAVELLY SAND (ARTIFICIAL FILL) "~ Sand, It. olive brown, well sorted, fine to medium *"- %P\\#£l! SAND, olive gray, well-sorted, very fine to fine, loose S 7 r5Pi 6 6 p^s 2 SP HilllHlllllllli very loose IT" SIS ~ Clay 5 t__ !Zrr^ O £:%:£ #* _ SAND, v. dk. greenish gray, well-sorted, fine to medium grained

7 _SE...... FINE SANDY LOAM, v. dk. greenish gray, loose 0 "5P" !!!!!!! " very loose

- CLAY, v. dk. greenish gray, soft (HOLOCENE BAY MUD)

------"1 5

O^~_~_~_~^_

Q " Z-E-E-^-C-- with shells

~O ______

SHELLS, 10-50% dk. greenish gray SAND 30

Figure 53. Geologic log for Treasure Island. 104 SITE: TREASURE ISLAND DATE: tu 'tu E 2 00 -I -JU. DESCRIPTION 00 0 -30-

SANDY LOAM, v. dk. greenish gray, some shells and gravel

-35

. CLAY

LOAMY FINE SAND, v. dk. greenish gray to olive gray

CLAY, dk. greenish gray, stiff to v. stiff (PLEISTOCENE BAY MUD)

[ "^T^^-^ -45

SAND

Figure 53. (Continued). 105 SITE: TREASURE ISLAND DATE:

UJ Q.-, ~ 00 in 0) DESCRIPTION -i u. l! O 6 CD CO O 60- SILTY CLAY, v. dk. greenish gray, stiff to v. stiff

SAND

75 FINE GRAVELLY SAND, dk. greenish gray

Pr .-:.//»»_ « .'. ; "80 " " SILTY CLAY, v. dk greenish gray

j-85

WOOD

SHALE, pale olive, deeply weathered, (FRANCISCAN ASSEMBLAGE) texture is SANDY CLAY 90

Figure 53. (Continued). 106 BLOWS/ FOOT CO o SAMPLE H CO TYPE m %vX*XvXvX*XvXvX*! £*i GRAPHIC 75 xx-J gggg:^^ LOG H i *«* %* * * * * * * * * * * * * * * * * *< %%*»*jl 1 1 1 1 1 j^ 1 1 1 1 1 1 1 1 1 j^ 1 I i i i i i DEPTH 30 (0 (O m I ro -* -* o o 01 O (motors) o 01 o 01 0 co i CO CO CO «C z > > >> o c CO ^ o IF n1 3D " O H * ? m z m i ~ - CO Q. 'm 5. g 1- CL 3 ?T < ,, (0 r O ^ 3 s & «s m z < tf> 01 - CD -< CO o K CD i5 "i, 5 o CO 0^7 ; 0) 5 r CD 5' CD r Q. Q. P- | H >'» CD ^ O CO r 31 Z 0> <

i' o H m S-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 0.4 0.5 0.1 0.2 0.3 0.4 0.5 .... i.... i.... i.... i....

Treasure Island

Figure 54. Horizontal-component record section from impacts in opposite horizontal directions superimposed for identification of shear arrivals. S-wave arrivals are shown by the accent marks.

108 P-WAVE Time (sec) Time (sec) 0.1 0.2 0.3 0 0.1 0.2

Treasure Island

Figure 55. Vertical-component record section. P-wave arrivals are shown by the solid circles.

109 Time (sec) 0.1 0.2 0.3 0.4 I I

20-

40 H

CD i »

80-

100-

Treasure Island

Figure 56. Time-depth graph of P-wave and S-wave picks. Line segments show the hinged-least-squares fit to the data points.

110 S Velocity (m/sec) 200 400 600 800 GRAVELLY SAND (ARTIFICIAL FILL)

SAND FINE SANDY LOAM CLAY (HOLOCENE BAY MUD) 20-

SHELLS SANDY LOAM

CLAY LOAMY FINE SAND ft CLAY PLEISTOCENE BAY MUD) 5"5 *,BI.Hi SAND £ £60 CD Q

so FINE GRAVELLY SAND

(FRANCISCAN ASSEMBLAGE)

SHALE j^jj^iU

SANDSTONE

Treasure Island

Figure 57. S-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the sloper^ (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

111 P Velocity (m/sec) o- 500 1000 1500 2000 2500 ;[; GRAVELLY SAND (ARTIFICIAL FILL)

. SAND FINE SANDY LOAM CLAY (HOLOCENE BAY MUD) 20- -

1?r»?.j' SHELLS SANDY LOAM .

^:;;l;;!:; 40- _ LOAMY FINE SAND *v> CLAY PLEISTOCENE BAY MUD)

+-» I SAND SS°~ - rtsr* 'ZS*f-£ H m £60- m Q m

9 &y* FINE GRAVELLY SAND 80-

(FRANCISCAN ASSEMBLAGE) ^^f "SHALE 'I'X'.'J

100- _ ::i!i:: _SANDSTONE

1 1 1 1 1 ' 111 1

Treasure Island

Figure 58. P-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

112 TABLE 11. S-wave arrival times and velocity summaries for Treasure Island.

d(m) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu

TRI.8 2-20-92 2:45p Paye 1 of 1 TABLE 12. P-wave arrival times and velocity summaries for Treasure Island.

d(m) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0069 1 -.5 .0 .0 .000 339 319 361 1111 1047 1183 5.0 16.4 .0086 -.4 2.5 8.2 .007 339 319 361 1111 1047 1183 7.5 24.6 .0115 .9 13.3 43.6 .014 1562 1428 1725 5126 4684 5659 10.0 32.8 .0130 .8 28.8 94.5 .027 1236 1182 1294 4054 3879 4245 12.5 41.0 .0143 .5 41.2 135.2 .036 1365 1297 1440 4477 4254 4725 15.0 49.2 .0155 -.2 75.0 246.1 .057 1583 1551 1617 5195 5088 5306 17.5 57.4 .0175 -.2 88.0 288.7 .064 1822 1704 1956 5976 5592 6417 20.0 65.6 .0186 -1.1 100.0 328.1 .070 2187 1957 2477 7174 6421 8127 22.5 73.8 .0207 -1.0 25.0 82.0 .0237 -.1 27.5 90.2 .0257 -.1 30.0 98.4 .0278 .1 32.5 106.6 .0308 1.2 35.0 114.8 .0318 .4 37.5 123.0 .0338 .6 40.0 131.2 .0348 -.2 42.5 139.4 .0368 .1 45.0 147.6 .0388 .5 _A 47.5 155.8 .0399 .0 . 50.0 164.0 .0419 .4 "T 52.5 172.2 .0429 -.2 * 55.0 180.4 .0439 -.7 Explanation: 57.5 188.6 .0459 -.3 60.0 196.9 .0469 -.9 d(m) = depth in meters 62.5 205.1 .0489 -.5 d(fl) = depth in feet 65.0 213.3 .0499 -1.1 67.5 221.5 .0529 .4 t(sec) = arrival time in seconds (S-wave arrival times are 70.0 229.7 .0539 -.2 the average of picks from traces obtained from 72.5 237.9 .0559 .2 75.0 246.1 .0579 .6 hammer blows differing in direction by 180°) 77.5 254.3 .0589 .3 sig = sigma, standard deviation normalized to the 80.0 262.5 .0609 .9 82.5 270.7 .0619 .5 standard deviation of best picks 85.0 278.9 .0629 .1 rsdl/sig = least-squares residual divided by sigma 87.5 287.1 .0639 -.2 90.0 295.3 .0649 -.4 dtb(m) = depth to bottom of layer in meters 92.5 303.5 .0659 -.6 dtb(ft) = depth to bottom of layer in feet 95.0 311.7 .0679 .3 97.5 319.9 .0689 .1 ttb(s) = arrival time in seconds to bottom of layer 100.0 328.1 .0699 1 .0 v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

TRI.P 2-20-92 2:44p Page 1 of 1 UNITED STATES PALO ALTO QUADRANGLE DEPARTMENT OF THE INTERIOR CALIFORNIA GEOLOGICAL SURVEY 7.5 MINUTE SERIES (TOPOGRAPHIC)

PALO ALTO VETERANS " HOSPITAL

SCALE 1:24000 o 1 MILE

1000 0 1000 2000_____3000 4000 5000 6000 7000 FEET F=r~E ' ' I ' ' ' ' ' '' I 1 KILOMETER

Figure 59. Site location map for Palo Alto Veterans Hospital. The borehole is located within 15 meters of the strong-motion recorder. 115 initions of terms used for descriptions of sedimentary deposits and bedrock materials

Rock hardness: response to hand and geologic Texture: the relative proportions of clay, silt, and hammer: (Ellen et al.( 1972) sand below 2mm. Proportions of larger particles are indicated ', by modifiers of textural class names. hard - hammer bounces off with solid sound Determination is made in the field mainly by feeling firm - hammer dents with thud, pick point dents or the moist soil (Soil Survey, Staff, 1951). penetrates slightly Sfjyft - pick points penetrates friable material can be crumbled into individual grains by hand.

Fracture spacing: (Ellen et al., 1972) cm in fracture soacina 0-1 0-1/2 v. close 1-5 1/2-2 close 5-30 2-12 moderate 30-100 12-36 wide >100 >36 v. wide

tAND Weathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: Standard Munsell color names are given for discoloration the dominant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of samples structure is preserved. i SP - Standard Penetration 1 + 3/8 in in ID sampler) S - Thin-wall push sampler Relative density of sand and consistency of clay is 0 - Osterberg fixed-piston sampler correlated with penetration resistance: (Terzaghi and P - Pitcher Barrel sampler Peck. 1948) CH - California Penetration (2 in ID sampler) DC - Diamond Core

relative blows/ft. density blows/ft. consistency

0-4 v. loose <2 v. soft 4-10 loose 2-4 soft

10-30 medium 4-8 medium

30-50 dense 8-15 stiff

>50 v. dense 15-30 v. stiff >30 hard

Figure 60. Explanation of geologic log.

116 SITE: PALO ALTO VETERANS HOSPITAL DATE: 8/29/90 SAMPE GRAPHIC BLOWS FOOT DEPTH TYPE LOQ (meters DESCRIPTION

CLAY, dk. grayish brown, v. stiff (LATE PLEISTOCENE ALLUVIUM)

24 C mottled brown and yellowish brown

SANDY CLAY LOAM, yellowish brown, (SANTA CLARA FORMATION) VV ^^" - 5 some fine gravel j*5j?.$ - FINE GRAVEL 52 £5. ;;;;;;; SANDY CLAY, pale brown

31 JJE 10 FINE GRAVEL SANDY CLAY LOAM, yellowish brown, up to 40% fine gravel 507 4* ,..,

1 5

507 ££ ;? '«£$ SANDY GRAVEL, dk. yellowish brown, poorly sorted 3* '^ o ^^ 20

P '.'.'.'.'.'.'.' SANDY CLAY LOAM, mottled pale brown and yellowish brown ^O

SANDY GRAVEL

strong brown 30

Figure 61. Geologic log for Palo Alto Veterans Hospital.

117 SITE: PALO ALTO VETERANS HOSPITAL DATE

UJ X « so 00 m DESCRIPTION -i u. oc Q E 0 O ___, 30 73 CA

yellowish brown

100 CA^ '.'.'.'.'.'.'. - strong brown

p ;;;;;;; yellowish brown

3-45

LOAM to SILTY CLAY LOAM, yellowish brown

FINE GRAVEL

SANDY CLAY LOAM, poorly sorted, 10-20% fine gravei -55

P -^'-C^v'

j/-;;^^ ~ K'»'riQ.".;'.?.v 60

Figure 61. (Continued). 118 SITE: PALO ALTO VETERANS HOSPITAL DATE: BLOWS/ SAMPLE GRAPHIC ^* FOOT x £ TYPE LOG **6 5 DESCRIPTION

ounn SANDY CLAY LOAM

y£ .??. ."?r oo FINE GRAVELLY SANDY CLAY LOAM, yellowish brown, v.dense

>3fe :i«>i/:>/V i't.'.'.'i>...'.''''.i: 60/ CA ^#£"W 6" > <.'' j'i fffffovy- .i.'V.-oO''"- -70 ^?ft ' t'^u-'-3 " #### " "t^vv-V'P

^^ P ^S^? -75 ':.^Wffy tf&te

:»;yg''»;.^'. g*>^^l^«"Prj FINE GRAVEL !'/ ;; ;'i>.V* ^.-^' !>w:;-yi' : . »? -80 507 I»A ' . V-'i'r- A 5* t-'>:'^'."''.tff; - ',- -;;'^-^ * U1'' ''* : '" i^iVvylJZ

^SS ^ ;-(Vv? oo ^^

^S% P .jri:*:::"? $^* SS^ .tl»,'."-''lAr' ^0

Figure 61. (Continued). 119 SITE: PALO ALTO VETERANS HOSPITAL DATE: BLOWS/ SAMPLE GRAPHIC <^s FOOT TYPE LOG £S Si? DESCRI PTION °3 on E-'VvV'fr sffiliffi Ci.'.»rAvj :X\*-.VAJ :; .#£' -.«] '. ;tVi.'.'i"'..'!'' '.'. ., '.'.^ ifo'''?''';'.'"'/.''? -95 ^y^i.ir-n5£*d CA" 507 ip%& 4* ***** » fiV^jliPi-- £.-.;: i^^1 -100

*£*& . 'liV.-.'.' .' ' ': £j£^> ;'-'-.'^'.^-'.

l!/;:^:-:?^;: --.g.-|f''if"i- ... .--.lii--,^ 1i n*>\j \j

'!' ( 'f'.'l'1 "..' .'.'.v;*V::?,. ,:f.'::P ? f ''; '.'.' '.' '! '' :'.' : .'»:; * : : : K->.;:..^.:1 i^^ - « »

»V. '« * ?". ; *- GRAVELLY SAND

.-»'«*. !*/*. " ; ** / .« »' ** *.**"-"* «-*.\ ." i-*" * * ; V '*-°** */. *.V: ";i:> * " *-*"/ "* "

" , o * * "-. " *

'' W&-J SANDY CLAY LOAM, strong brown ^ ^»

t^..'. > -vy.-i :.g:'V'-j?'!.- Ion£.\J

Figure 61. (Continued). 120 SITE: PALO ALTO VETERANS HOSPITAL DATE: BLOWS/ GRAPHIC *^, SAMPLE i S FOOT TYPE LOG S 1 DESCRIPTION « J ion *' # '» "»?.;v,;-: P ;/ ;' # #; ': '." .' : .'. ' .'»-g ; ' - ; <> ..' ! -ft-: ttt:-& '.g.-.' :; * .': i ^Io . . ; >.;. »-v"i0.v-. '. . ^- .' : *3*±& '-' I"'

' ^'. : '^?/.' v; :»: '/:.'; <>'.. ' ; ; ' rlT^i -130 L'^I.'-. ^/*.% SILTSTONE, greenish gray, firm (MERCED FORMATION?)

-135

P -140 GRAVELLY

M»

-145

-150

Figure 61. (Continued). 121 S-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 0.1 0.2 0.3 0.4 0

.*%.H '.^^ f \^\ ^.^*"V"X'V^ti

Q_ CD O v v^ 2C2e&~*$}i^^

^^<^^^^

Veterans Hospntal - Palo Alto

Figure 62. Horizontal-component record sectiori from impacts in opposite horizontal directions superimposed for identification of shear arrivals. S-wave arrivals are shown by the accent marks.

122 P-WAVE Time (sec) Time (sec) 0 0.1 0.2 0.3 4 0 0.1 0.2 0.3 0.4 o -mN v^Ww-^ i ^j^^^f^^^^

JZ H ' Q_ CD Q

l^l\j\^^

Veterans Hospital - Palo Alto

Figure 63. Vertical-component record section. P-wave arrivals are shown by the solid circles.

123 Time (sec) 0.05 0.1 0.15 0.2 0.25 0.3 i

50-

150-

VA Hospital (Palo Alto)

Figure 64. Time-depth graph of P-wave and S-wave picks. Line segments show the hinged-least-squares fit to the data points.

124 S Velocity (m/sec) 200 400 600 800 1000

(LATE PLEISTOCENE ALLUVIUM)

SANDY CLAY LOAM (SANTA CLARA FORMATION) SANDY CLAY GRAVELLY SANDY CLAY LOAM

SANDY GRAVEL

SANDY CLAY LOAM

50- FINE GRAVEL

SANDY CLAY LOAM

GRAVELLY SANDY CLAY LOAM *-«

GRAVELLY SAND

1MERCED FORMATION?)

150-

VA Hospital (Palo Alto)

Figure 65. S-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the £lope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities. i

125 P Velocity (m/sec) 500 1000 1500 2000 2500 3000

(LATE PLEISTOCENE ALLUVIUM)

SANDY CLAY LOAM (SANTA CLARA FORMATION) SANDY CLAY

GRAVELLY SANOY CLAY LOAM

. SANDY GRAVEL

SANDY CLAY LOAM

50- m FINE GRAVEL SANDY CLAY LOAM co GRAVELLY SANDY CLAY LOAM JD"S E

GRAVELLY SAND

(MERCED FORMATION?)

150-

VA Hospital (Palo Alto)

Figure 66. P-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

126 TABLE 13. S-wave arrival times and velocity summaries for Palo Alto Veterans Hos pital.

d(m) d(ft) t(sec) si*9 rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0180 1 .5 .0 .0 .000 143 139 146 468 456 480 5.0 16.4 .0250 1 -.6 3.0 9.8 .021 143 139 146 468 456 480 7.5 24.6 .0313 1 -.1 12.5 41.0 .043 437 421 453 1432 1381 1487 10.0 32.8 .0376 1 .5 19.0 62.3 .067 273 264 282 895 866 926 12.5 41.0 .0433 1 .5 24.2 79.4 .077 512 474 556 1680 1556 1825 15.0 49.2 .0507 1 -1.3 35.0 114.8 .092 705 673 739 2313 2210 2426 17.5 57.4 .0614 1 .3 60.0 196.9 .138 544 536 552 1785 1759 1811 20.0 65.6 .0686 1 .0 80.0 262.5 .170 624 610 640 2048 2000 2099 22.5 73.8 .0743 1 .8 115.0 377.3 .237 520 512 527 1705 1681 1730 25.0 82.0 .0770 1 -.9 147.4 483.6 .275 854 818 894 2802 2683 2932 27.5 90.2 .0821 1 .6 30.0 98.4 .0847 1 -.3 35.0 114.8 .0919 1 -.2 40.0 131.2 .1010 1 -.3 45.0 147.6 .1116 1 1.1 50.0 164.0 .1196 1 -.1 55.0 180.4 .1282 1 -.7 60.0 196.9 .1387 1 .6 65.0 213.3 .1457 1 -.4 Explanation: 70.0 229.7 .1537 1 -.4 d(m) = depth in meters 75.0 246.1 .1623 1 .2 80.0 262.5 .f708 2 .3 d(ft) = depth in feet 85.0 278.9 .1808 c t(sec) = arrival time in seconds fS-wave arrival time»are 90.0 295.3 .1888 2 -.3 95.0 311.7 .1978 2 -.6 the average of picks from traces obtained from 100.0 328.1 .2078 2 -.4 hammer blows differing in direction by 180°) 105.0 344 **T"? 5^ .2193 2 .5 110.0 360.9 .2278 2 .0 sig = sigma, standard deviation normalized to the 115.0 377.3 .2374 2 .0 120.0 393.7 .2439 2 .3 standard deviation of best picks 125.0 410.1 .2499 2 .4 rsdl/sig = least-squares residual divided by sigma 130.0 426.5 .2549 2 -.1 135.0 442.9 .2589 2 -1.0 dtb(m) = depth to bottom of layer in meters 142.5 467.5 .2699 4 .1 dtb(ft) = depth to bottom of layer in feet 147.4 483.6 .2789 4 .9 ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

VAH.S 2-20-92 2:47p Pag* 1 of 1 TABLE 14. P-wave arrival times and velocity summaries for Palo Alto Veterans Hos- pital.

d(m) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vUm/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 2.5 8.2 .0079 1 -.3 .0 .0 .000 306 297 316 1004 973 1037 5.0 16.4 .0117 1 .1 3.0 9.8 .010 306 297 316 1004 973 1037 7.5 24.6 .0141 1 .3 12.5 41.0 .018 1132 1071 1201 3715 3514 3939 10.0 32.8 .0158 -.2 19.0 62.3 .021 2314 1978 2787 7592 6489 9145 12.5 41.0 .0181 -.1 24.2 79.4 .024 1732 1494 2059 5681 4901 6757 15.0 49.2 .0193 .0 35.0 114.8 .029 2019 1872 2190 6623 6143 7184 17.5 57.4 .0205 .1 60.0 196.9 .043 1843 1800 1888 6047 5905 6195 20.0 65.6 .0216 .0 132.5 434.7 .078 2089 2073 2105 6854 6802 6906 22.5 73.8 .0226 -.4 147.4 483.6 .086 1747 1684 1815 5732 5525 5955 25.0 82.0 .0247 .3 27.5 90.2 .0257 .1 30.0 98.4 .0268 -.1 35.0 114.8 .0298 .4 40.0 131.2 .0318 -.3 45.0 147.6 .0349 .1 50.0 164.0 .0369 -.6 55.0 180.4 .0399 -.3 . 60.0 196.9 .0429 .0 rr 65.o 213.3 .0459 .6 *> 70.0 229.7 .0479 .2 00 75.0 246.1 .0499 -.2 Explanation: 80.0 262.5 .0519 -.6 85.0 278.9 .0549 .0 d(m) = depth in meters 90.0 295.3 .0569 -.4 d(ft) = depth in feet 95.0 311.7 .0599 .2 100.0 328.1 .0629 .8 t(sec) = arrival time in seconds (S-wave arrival times are 105.0 344.5 .0650 .5 the average of picks from traces obtained from 110.0 360.9 .0670 .1 115.0 377.3 .0690 -.2 hammer blows differing in direction by 180°) 120.0 393.7 .0720 .4 sig = sigma, standard deviation normalized to the 125.0 410.1 .0740 .0 130.0 426.5 .0760 -.4 standard deviation of best picks 132.5 434.7 .0770 -.6 rsdl/sig = least-squares residual divided by sigma 135.0 442.9 .0790 -.1 137.5 451.1 .0810 .5 dtb(m) = depth to bottom of layer in meters 140.0 459.3 .0820 .1 dtb(ft) = depth to bottom of layer in feet 142.5 467.5 .0830 -.3 145.0 475.7 .0850 .2 ttb(s) = arrival time in seconds to bottom of layer 147.4 483.6 .0860 -.2 v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

VAN.P 2-20-92 2:47p Page 1 of 1 APPROXIMATE 100 FOOT__|

BOREHOLE LOCATION

PARKING LOT

LIGHTHOUSE RETAILING WALL CONCRETE CDMG STEPS INJSTRUMfcNT EMPTY CONCRETE UiLDING DECK

Project No. 90C0588A Field Exploration U.S. COASTGUARD YERBA13UENA ISLAND SITE Woodward-Clyde Consultants

Figure 67. Detailed map showing location of the borehole relative to the strong-motion recorder. 129 UNITED STATES OAKLAND WEST QUADRANGLE DEPARTMENT OF THE INTERIOR CALIFORNIA GEOLOGICAL SURVEY 7.5 MINUTE SERIES (TOPOGRAPHIC)

\ . r~**<"/ -^H

CONTOUR INTERVAL 20 FEET Figure 68. Site location map for Yerba Buena Island (same as Figure 49). 130 Defirations of terms used for descriptions of sedimentary deposits and bedrock materials

Rode hardness: response to hand and geologic Texture: the relative proportions of clay, silt, and hammer: 4EUenetal.. 1972) sand below 2mm. Proportions of larger particles are indicated by modifiers of textural class names. hard - hammer bounces off with solid sound Determination is made in the field mainly by feeling 1irm - hammer dents with thud, pick point dents or the moist soil (Soil Survey, Staff, 1951). penetrates slightly soft - pick points penetrates friable material can be crumbled into individual grains by hand.

Fracture spacing: (Ellen et al., 1972) cm in fracture soacina Q-1 0-1/2 v. close 1-5 1/2-2 close $-30 2-12 moderate 30-100 12-36 wide ^100 >36 v. wide

Weathering: Fresh: no visible signs of weathering Slight: no visible decomposition of minerals, slight Color: Standard Munsell color names are given for discoloration the dominant color of the moist soil and for Moderate: slight decomposition of minerals and dis prominent mottles. integration of rock, deep and thorough dis coloration Deep: extensive decomposition of minerals and complete disintegration of rock but original Types of ssamples structure is preserved. SP - Standard Penetration 1 + 3/8 in in ID sampler) S - Thin-Wall push sampler Relative density of sand and consistency of clay is 0 - Osterberg fixed-piston sampler correlated with penetration resistance: (Terzaghi and P - Pitcher Barrel sampler Peck. 1948) CH - California Penetration (2 in ID sampler) DC - Diamond Core

relative Wowsrtt. density falowsfft. consistencv

O-4 v. loose <2 v. soft IMO loose 2-4 soft 1O-30 medium 4-8 medium 30-50 dense 8-15 stiff >50 v. dense 15-30 v. stiff >30 hard

Figure 69. Explanation of geologic log.

131 SITE: YERBA BUENA ISLAND DATE: 10/25/90 BLOWS/ SAMPLE GRAPHIC ^ FOOT i « TYPE LOG &5 DESCRIPTION oj

:^vv-v ;' GRAVELLY SAND, some asphalt fragments SANDSTONE, yellowish brown, moderately weathered, firm fragments to 20 cm

deeply weathered, texture is SANDY CLAY LOAM

-5

SS&'iv X.yXv ~ SANDSTONE, v.dk. yellowish brown, moderately weathered, v. firm, moderately fractured S&xS>: : : >: : :&88& ^

-10 v. firm to hard

§:* * *: * :$&* * * !

>IvXvX -15 SANDSTONE, dk. gray, fresh, hard, moderate to wide fracture spacing

SSiSiS:: : : : : : :

^ - ^ ^ . - - _ ~~ Interbedded SHALE and SANDSTONE, close to moderate fracture spacing

^ ,^^_^_^^i r20 SHALE, black, hard, v. close to close fracture spacing

-MMH*M _ _ .._. DC -25

-30

Figure 70. Geologic log for Yerba Buena Island.

132 S-WAVE Time (sec) o

jjff$^^

Yerba Buena

Figure 71. Horizontal-component record section from impacts in opposite horizontal directions superimposed for identification of shear arrivals. S-wave arrivals are shown by the accent marks.

133 P-WAVE Time (sec) o 0.1 0.2 o 2

6 ^[^^ '

8 10

H 12 8- 14 o 16

20 '^\/\^(\J\J\f^^^

Yerba Buena

Figure 72. Vertical-component record section. P-wave arrivals are shown by the solid circles.

134 Time (sec) 0.01 0.02 0.03 0.04 0.05 »

2 ID 'S E

Q. 0 Q

20 H

Yerba Buena Island

Figure 73. Time-depth graph of P-wave and S-wave picks. Line segments show the hinged-least-squares fit to the data points.

135 S Velocity (m/sec) 200 400 600 800 1000 1200 GRAVELLY SAND SANDSTONE deeply weathered

SANDSTONE moderately weathered

1JT 10H £"S E

Interbedded SHALE and SANDSTONE 20 H SHALE

Yerba Buena Island Figure 74. S-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

136 P Velocity (m/sec) 500 1000 1500 2000 GRAVELLY SAND SANDSTONE deeply weathered

SANDSTONE moderately weathered

co40 10- "55<5

interbedded SHALE and SANDSTONE 20- SHALE

Yerba Buena Island Figure 75. P-wave velocity profiles with dashed lines representing plus and minus one standard deviation. The statistics are done on the slope (reciprocal velocity) so that some of the limits will not appear symmetrical. Simplified geologic log is shown for correlation with velocities.

137 TABLE 15. S-wave arrival times and velocity summaries for Yerba Buena Island.

d(ffl) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) I.0 3.3 .0026 0 .0 .000 385 352 424 1262 1155 1391 3.0 9.8 .0103 -.1 1.0 3.3 .003 385 352 424 1262 1155 1391 s.o 16.4 .0154 -.2 3.0 9.8 .010 257 247 268 844 812 878 7.0 23.0 .0211 .3 11.0 36.1 .031 385 380 391 1264 1246 1282 9.0 29.5 .0261 .1 15.0 49.2 .037 681 651 714 2235 2137 2342 II.0 36.1 .0309 -.2 23.5 77.1 .046 982 941 1027 3221 3086 3369 13.0 42.7 .0341 .0 15.0 49.2 .0368 -.2 17.0 55.8 .0394 .3 19.0 62.3 .0410 -.1 21.0 68.9 .0431 .0 23.5 77.1 .0456 .0

CO CD Explanation: d(m) = depth in meters d(ft) = depth in feet t(sec) = arrival lime in seconds (S-wave arrival times ar the average of picks from traces obtained from hammer blows differing in direction by 180°) sig = sigma, standard deviation normalized to the standard deviation of best picks rsdl/sig = least-squares residual divided by sigma dtb(m) = depth to bottom of layer in meters dtb(fb) = depth to bottom of layer in feet ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = lower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

YBI_S.COL 3-26-92 2:27p Page 1 of 1 TABLE 16. P-wave arrival times and velocity summaries for Yerba Buena Island.

d(m) d(ft) t(sec) sig rsdl/sig dtb(m) dtb(ft) ttb(s) v(m/s) vl(m/s) vu(m/s) v(ft/s) vl(ft/s) vu(ft/s) 1.0 3.3 .0016 1 .0 .0 .0 .000 630 579 691 2068 1901 2267 3.0 9.8 .0064 1 .0 1.0 3.3 .002 630 579 691 2068 1901 2267 5.0 16.4 .0111 1 -.2 5.0 16.4 .011 413 405 422 1356 1328 1384 7.0 23.0 .0129 1 .2 11.0 36.1 .016 1415 1361 1474 4643 4465 4836 9.0 29.5 .0142 1 .1 23.5 77.1 .022 1848 1796 1904 6064 5892 6246 11.0 36.1 .0154 1 -.1 13.0 42.7 .0166 1 .0 15.0 49.2 .0177 1 .0 17.0 55.8 .0187 1 -.1 19.0 62.3 .0198 1 .0 21.0 68.9 .0208 1 -.1 23.5 77.1 .0228 2 .3

00 CO Explanation: d(m) = depth in meters d(ft) = depth in feet t(sec) = arrival time in seconds (S-wave arrival times are the average of picks from traces obtained from hammer blows differing in direction by 180°) sig = sigma, standard deviation normalized to the standard deviation of best picks rsdl/sig = least-squares residual divided by sigma dtb(m) = depth to bottom of layer in meters dtb(ft) = depth to bottom of layer in feet ttb(s) = arrival time in seconds to bottom of layer v(m/s) = velocity in meters per second vl(m/s) = tower limit of velocity in meters per second * vu(m/s) = upper limit of velocity in meters per second v(ft/s) = velocity in feet per second vl(ft/s) = lower limit of velocity in feet per second vu(ft/s) = upper limit of velocity in feet per second * see text for explanation of velocity limits

YBI_P.COL 3-26-92 2:27p Page 1 of 1