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. -. 44 ¶4 4' 4 4,.. 4 0 0 2 2 2 .4 GS.92.M.0 - INFORMATION ONLY 2 - I
USGS-OFR-92-340 USGS-OFR-92-40O
UNITED STATES DEPARTMENT OF THE INTERIOR -GEOLOGICAL SURVEY
FOR THE SOUTHERN GREAT BASIN SEISMICITY AND FOCAL MECHANISMS ' OF NEVADA AND CALIFORNIA IN 1991 '4'.1
by ,-S.C. Harmsen
Open-File Report 92-340
'1-1 r4
Prepared In cooperation with the 4.4 Nevada Field Office U.S. Department of Energy (Interagency Agreement DE-AI08-92NV10874)
with is preliminary and has not been reviewed for conformity This report nomenclature. U.S. Geological Survey editorial standards and stratigraphic and do not constitute Company names are for descriptive purposes only endorsement by the U.S. Geological Survey.
Denver, Colorado 1993
940411 PDR9405030227 WASTE
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USGS-OFR-92-340 USGS-OFR-92-340
UNITED STATES DEPARTMIENT OF THE INTERIOR 4'ý GEOLOGICAL SURVEY
Denver, Colorado
SEISIICITY AND FOCAL MECHANISMS FOR THE SOUTHERN GREAT BASIN
OF NEVADA AND CALIFORNIA IN 1991
by
S. C. Harmijen
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Page Abstract I Introduction I Acknowledgments 3 Calibration of Instruments ...... 3 Data Acquisition and Integration into the Catalog ...... 3 Seismicity of selected areas in 1991 ...... 8 Yucca Mountain area...... 8 Bare Mountain area ...... 8 Death Valley-Furnace Creek ...... 11. Amargosa Desert ...... 13 Pahranagat Shear Zone, Nevada ...... 14 Las Vegas Valley Earthquakes ...... 14 SGB Earthquake Focal Mechanisms for 1991 ...... 17 Conclusions...... 24 References cited 29 Appendix A. SGB -arthquake locations for 1991, and quadrangle names . ... 31 Appendix B. Chemical explosion location'data for 1991...... 59 "" Appendix C. Nuclear device tests and induced low-frequency shallow seismicity in the NTS, 1991...... 7 th NT,1 9 ...... • 6 Appendix D. Southern Great Basin earthquake focal mechanisms for 1991 . . . 74 Appendix E. Station codes, locations and site geology, and instrumentation 93 Appendix F. Input parameters to HYPO71 ...... 99 ILLUSTRATIONS Figures 1-11.-Map showing':- .
1.- SGBSN station locations, cities and towns, and some major physiographic ' features of the southern Great Basin ...... 2 2.- Earthquake epicenters in the southern Great Basin, 1991 ...... 5 3.- Maximum earthquake magnitude per 7/-minute by 71-minute topographic quadrangle in the interior of the southern Great Basin for earthquakes of 1991 7 4.- Seismicity and focal mechanisms for earthquakes near the volcanic caldera complexes of western Nevada Test Site for 1991 ...... 9 5.- Seismicity at and near the volcanic caldera complexes of western Nevada Test Site for the period August 1978 through December 1990 ...... 10 6.- Earthquake epicenters in the vicinity of Death Valley, California, for 1991, and faults that may lýave had siurface movement in the last two to three million years ...... 12 7.- Preliminary epicenters and focal mechanism for the larger earthquakes of 1991 in the vicinity of Pahranagat Shear Zone, Nevada ...... 15 8.- Seismicity for the same region as in figure 7 for the period 1984-90 . 16 9.- Seismicity recorded in the vicinity of Las Vegas Valley, Nevada, and Nellis Air Force Range east of NTS for 1991 ...... 18 10.- Seismicity recorded in the vicinity of Las Vegas Valley, Nevada, and Nellis Air Force Range east of NTS for the period 1984 through 1990 ...... 19
iii !\ II.-- Epicenters and associated focal mechanisms for the 14 largest southern Great Basin earthquakes of 1991 for which mechanism solutions could be de
termined ...... F21 Figure 12.- Lower hemisphere showing inclinations (plunges) and azimuths of 14 focal mechanism preferred solution P-axes and T-axes for southern Great Basin earthquakes of 1991 having ML> 1.4...... 22 Figure 13.- Lower hemisphere showing intersection of compressional quadrants and dilatational quadrants for l4 southern Great Basin focal mechanisms of 1991 23 Figure 14.- Left Side: Plots of fixed-depth and free-depth epicenters for HYPO71 hypocenters for selected earthquakes for which focal mechanisms were prepared. Right Side: Plots of RMS traveltime residual as a function of assumed depth of fous...... 25 Figure 15.- Same meaning of two sides as in figure 14. Upper pair of graphs is for the saz&e earthquake data as the lowier pair; only the manner in which arrival time data were weighed is changed...... 28 Figure Al.- USGS topographic quadrangle names in the northeast quarter of the southern Great Baiin ...... 32 Figure A2.- USGS topographic quadrangle names in the southeast quarter of the southern Great Basin ...... 33 Figure A3.- USGS topographic quadrangle names in the northwest quarter of the southern Great Basin ...... 34 Figure A4.- USGS topographic quadrangle names in the southwest quarter of the southern Great Basin ...... 35 Figure BI.- Map showing epicenters of detected chemical explosions in the southern Great Basin for 1991 ...... 60 Figure CI.- Map showing epicenters of announced NTS nuclear device tests of 1991 and some low-frequency earthquake epicenters ...... 68 "Figure C2.- SeiSmograms from several SGBSN stations for two or more induced low-frequency events occurring about 5 hrs after the Silent Canyon nuclear device test BEXAR (1991-04-04) ...... 69
Figures DI-DI$.- Focal mechanism solutions for:
DI.- An Amargosa Desert (Fortyrnile Wash, NTS) earthquake of January 5, 1991 ...... 74 D2.- An Indian Springs, Nevada earthquake of March 1, 1991 ...... 75 D3.- Lower Pahranagat Lake SW earthquake of March 10, 1991 . . .. 76 D4.- A Bare Mtn. earthquake of March 12, 1991 ...... 77 D5.- Amargosa Desert earthquake of April 13, 1991 ...... 78 D6.- Lower Pahranagat Lake SW earthquake of April 15, 1991 ...... 79 D7.- Stovepipe Wells earthquake of May 15, 1991 ...... 80 D8.- Sarcobatus Flat earthquake of June 8, 1991 ...... 81 D9.- Sarcobatus Flat earthquake of June 12, 1991 ...... 82 DID.- Frenchman Flat earthquake of June 14, 1991 ...... 83 DII.- Timber Mountain earthquake of June 18, 1991 ...... 84 D12.- Timber Mountain earthquake of July 4, 1991 ...... 85 D13.- Indian Springs earthquake of July 12, 1991 ...... 86 D14.- Gold Mountain earthquake of August 5, 1991 ...... 87 D1S.- Lower Pahranagat Lake SE earthquake of November 7, 1991 . . . 88
iv
P Figures DI.- Alternate focal mechanism solutions for Lower Pahranagat Lake SE earthquake of November T,1991 ...... "...... 89 Figures D17.- Focal mechanism solutions for Specter Range NW earthquake of November 30, 1991 .' - (...... 90 Figure D18.- Graphi of angle of nodal plane slip versus dip for focal mechanism solutions for earthquake of figure D17 ...... I...... 91 Figure Fl.- Standard and Yucca Mountain P- and S-wave velocity models used in preliminary SGB hypocenter determinations ...... 100
LIST OF TABLES Table 1.- Selected statistical characteristics of a subset of the 1991 SGBSN earth quake catalog .'...... 7 Table 2.- Summary of preliminary location parameters for three earthquakes located in the Claim Canyon Cauldron segment north of Yucca Mountain, Nevada, in 1991 ...... Table 3.- Preliminary southern Great Basin earthquak,, foc.2! mechanisms for 1991 20 Table CI.- Announced NTS nuclear device tests at Nevada Test Site in cdlendar year 1991, ...... 67 Table El.- Major components in seismographic systems comprising the Sa BSN in 1991 ...... -92 ., Table E2.- SGBSN station site geology (preliminary) ...... 93
(0(
V Seismicity and Focal Mechanisms for the Southern Great Basin of Nevada and California ln 1991 ABSTRACT,
For calendar year 1991, the southern Great Basin seismic network (SGBSN) recorded 980 earthquakes in the SGB, as compared to 1050 in 1990. Local magnitudes, ML, ranged from 0.0 for several earthquakes in the southern Nevada Test Site to 4.1 for a-strike-slip earthquake in the Lower Pahranagat Lake SW quadrangle on March 10, 1991. No felt-reports or damage reports were filed with the National Earthquake Information Center (NEIC) for Southern Great Basin (SGB) earthquakes of 1991, although public agencies were canvassed following three of the largest of them. Within a 10-kiu radius of the site 'of a potential national, high-level nuclear waste repository near the center of Yucca Mountain, Nevadza, no earthquakes were detected, although three earthquakes, with duration magnitudes between 0.8 and 1.1, were recorded in the Claim Canyon Cauldron segment south of Timber Mountain and 10+ kmn, north of the potential repository site. The estimated focal depths of these earthquakes are 3.6 km to 4.9 km below sealevel. Other, smaller events also may~have occurred in the immidiate vicinity of Yucca Mountain, but would have been below the network's leteLtion threshold (ML r 0.0 at Yucca Mountain). Twelve earthquakes were' located in 1.991 at Bare Mountain, Nevada, six of them on or near a fault along the northwestern flank of Bare Mountain. Focal mechanisms for 16 SGB earthquakes of 1991 with magnitudes in the range 0.85 ML _4.1 are predominantly strike slip. Normal slip occurred for an earthquake at Gold Mountain, Nevada, and oblique dip slip strike slip is determined for earthquakes at Sarcobatus Flat, Nevada; Pahranagat Shear Zone, Nevada;'and Frenchmrian Flat, Nevada Test Site (NTS). One nodal small (ML 1.3) eaithquake in the Amargosa Desert; California, displays subhorizontal planes for its focal mechanism solutions, indicating the possibility of a seismically active detach 0 ment fault. The azimuth of the average tension axis for preferred focal mechanism solutions of 14 earthquakes of 1991 having ML, > 1.4 is North 570 West (data from smaller earthquakes were not included in this statistic). -INTRODUCTION
The SGBSN has operated' ontinuously since August 1978, with 54 vertical-component stations deployed since mid-1981. Horizontal-component seismographs were added at selected sites in 1984, and a vertical-component seismograph south of Boulder City, Nev., was added in August 1988. Figure 1 shows seismograph station locations and some of the major physiographic features of the southern Great Basin of Nevada and California. Appendix E tabulates seismo graph station info.-ma'ion and station-site geology. The primary purpose of the network is to monitor seismnicity in the vicinity of Yucca The Mountain, Nevada, the'potential site of a high-level, national nuclear-wa!ste repceitory. network also provides information on seismotectonics within a P160-km radial distance of Yucca U.S. Geological Mountain. Seismic signals from the network are continuously telemetered to the are Survey (USGS) data processing center in Golden, Col., where preliminary hypocenters "determinned, along with research on focal mechanisms and faulting, on fluid-induced seismicity, to the on seismic-wave attenuation, on velocity structure, and on other topics of imprortance Yucca Mountain Project. De Operation of the seismic network is funded by an interagency agreement with the analysis, partment of Energy, which provides quality-assurance guidelines for the collection, network data are interpretation, and reporting of Yucca Mountain Project data. The seismic seismicity data in collected as permanent records to support site -characterization. Because known, the the SGB come from sources and crustal paths that are, at best, approximately
1
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I 115o 114.50 ( 1180 1170 1160
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.60 v a~OCZLT'G ZTR1M PM-Pahut a Mesa YF- Yu cc& F1at Oa IT ona?0W RU-Ralnier Uses MR-Mon~tezumla Range T M-Ti mbeor Mtn. LVV-Laa Ve9ga Valley 3 F-Uar cobatwa Ftlat CF-Ct at at Ft %It, MV-Morcuty Valley1 OV-0O *Ia V allIey SR-Specter Range LU-Lake Meld LCR-Laat chance flange' Y U-Yucca Utn. EM-El dorado Mtn@. GVM-arapovlfle MItts. 11M-Ba2re Mitn. FF-Frenchmnan Ftlat palM-palmetto Mins. NTS-N~vada Test Sits,
Figure 1-.- SG BSN seismrograph station*locatioiis. cities and towns, and some major phys iographic featlires of the southern (reat Basin.
2 hypocenters and analyses that are presented in open-file format are necessarily preliminary. Any "final' report of seismicity in the SGB should integrate information from all relevant sources, whereas the open-file reports (OFR's) of SGB seismicity periodically published by the USGS, such as this one, are less comprehensive. OFR's for previous years are listed in the References Cited section. All hypocenters and focal mechanisms appearing In this and previous SGB seismlcity reports are preliminary. - '.Seismic station density will be increased, first in the vicinity of Yucca Mountain, Nevada, and then in the surrounding region, during implementation of the seismic network upgrade, a cooperative project among the USGS, the University of Nevada at Reno Seismology Lab, and the U.S. Department of Energy. The upgrade will consist of three-component broadband seismome "ters and digital satýellit, telemetry to a downlink center, probably at Golden, Col. and various computer systems for data analysis, redistribution, and archiving. During fiscal year 1991, progress was made on seismic station site selection and permitting, equipment purchasing and installation, software development, and all other aspects of that project. Instruraent deployment and data acquisition frorm the upgrade network are scheduled to begin in fiscal year 1992. Acknorwledgw'aenbsu "Maintenance and periodic calibration of seismograph stations and related field equipment are performed by D. E. Overturf and W. T. Bice of the USGS, and by contract technicians. Most preliminary ceismic event catagorizations, phase arrival time determinations, and initial hypocenter determinations for SGB seismicity of 1991 were performed by J. B. Duggar of the :USGS. -- . of Helpful'technical reviews of this report were provided by 3. S. Gomberg and H. M. Benz of the USGS, Branches of Geologic Risk Asesmient and Seismology, respectively. Corrections to the original draft and observations by W. J. Carr on the geology of the southern .Great M Basin have been incorporated into the text and figures and are gratefully acknowledged. It is emphasized here, however, that this report is a catalog of Peismicity, not of geology. All fault _t' -traces shown in the figures of this report are from Rogers and others (1983, pl. 1). "CALIBRATION OF INSTRUMENTS All seismographic systems in the SGBSN are periodically calibrated as specified in the quality-aisurance document, YMP-USGS Seismic Procedure.11. Seismometers and related equipment are inspected and calibrated annually, or as needed. Calibration results are deemed acceptable when the amplitude response of a seismographic system lies within a ±30% range of a nominal (expected) response, in the frequency. band.2 _5f _<10 Hz. In actual field calibrations, systems ari tested in the frequency band 0.1 < f.: < 20 Hz. In these calibrations,,Teledyne 'Geotechl S13 systems (see Appendix E) generallydisplay an amplitude response within 10% -of the nominal level at all measured frequencies,' and Mark Products' L4C systems display responses within 25% of their nominal levels for frequencies I _ -to obtain ML estimates, are almost always less than 0.5 seconds (frequency > 2 Hz). 'DATA'ACQUISITION AND INTEGRATION INTO THE CATALOG * ,-Hypocenter data for, all SGB earthquakes occurring during calendar year 1991 for which preliminary event locations could be determined are listed in Appendlix A. SGB earthquake SUse of trade names is for descriptive purposes only and does not constitute endorsement by the USGS. 3 z 1- epicenters for 1991 are displayed in figure 2. The southwestern pari of the region (west of the Panamint Range, Calif.) shownin figure 2 is more densely covered by the USGS/California Institute of Technology seismic network at Pasadena', California;' and any study of strain and seismicity rates in the southwestern SGB'would benefit by'adding data from their catalog to the SGBSN catalog. Other parts of the SGB shown in figure- are sparsely covered by SGBSN stations, or are not covered at all. Several subregions of the SGB have been the targets of short duration local seismicity studies ionducted by various laboratories;' but; in general, their data have not been added to the SGBSN catalog. The SGBSN also archives regional and teleseismic dat'a and regularly provides selected event seismograms to interested investigators . Hypocenter information for chemical explosions and probable explosions that were located by the SGBSN are listed in Appendix B, and corresponding epicenters are shown in Appendix B, figure BI. Hypocenter information for announced nuclear device tests detonated during 1991 at Nevada Test Site (NTS) are listed in Appendix C; and their epicenters are shown in figure C1. Some epicenters of tectonic rele 'aefrom nuclear device detonations and associ..ted cavity col "lapses located in the Silent Canyon Caldera and Yucca Flat are denoted by OL" (low-frequency event) in figures 2, 4, 5, and Cl. Hypocenter information for located NTS low-frequency events is listed in Appendix C, table C2. Focal mechanisrrm solutions computed from SGBSN station seismograms for 16 eurthquakes of 1991 are'shown in the figures of Appendix D. Appendix E contains station information, anrd Appendix F' contains informatioii about hypocenter location (HYPO71) input parameters, such as seismic velocities. The seismogram data from which the earthquaike hypocente-s are determined (Appendix A) were digitized by a Digital Products PDP 11/341 computer, dedicated to seismic event detection. The time:domain~event,-detection algorithm is that of Johnson (1979). Data are also recorded on 16rmillimeter Develocorder films, which serve aa a backup to the computer detection system. Events whose arrival-time data arie read from Develocorder records are labeled 'As in the third character of the three-letter 'quality field"- of each hypocenter record of Appendix A. Measurements made from CRT-displayed digital seismograms are generally more reliable than tl3ose scaled from films, with irmpulsive P- and S-arrivals being determined to an accuracy better than 0.02 to 0.04 sec (digitizing rate=104.167 sps/channel), versus 0.10 sec for most P arrivals read from Develocorder filnm (S-arrivals scaled from film are much more uncertain than corresponding P-zirrivals). Hypeocenters derived from computer-recorded events are labeled 'I* in the'q4ality field. The PDP seismic computei downtime averaged about 71percent per month during 1991, principally due to hardware problems and'to magnetic tapes filling. Seismograms from all SGBSN stations that display a moderate to good signal-to-noise ratio for a giveii l6ial earthquake detected by the' acquisition system' are"permanently archived on UNIX star*-format magnetic tapes. Copies of these tapes are periodically distributed to the USGS-Yucca Mountain Project (YMP) Local Records Center arid are available to investigators after annual seismicity reports are published, when 'approved by USGS-YMP management. Develocorder film data are also permanently archived. A variety of -iainitide"may be computed from SGBSN waveform data for each earthquake and blast rep6rted ini Appendixes A' and B. As many as five magnitude estimates are determined per event: (1) coda--avernge magnitude, Me,,; (2) duration magnitude, MD; (3) local magnitude from horizontal compont nt instruments MA`r; (4) local magnitude from vertical component instruments, MZ'"; and :5) local magnitude from clipped records, M.. These are discussed in previous SGBSN date. reports (Rogers and oth'ers, 1987b; Harmsen and Bufe, 1991). Figure 3 shows the maximum 19C. 1 earthquake magnitude [avg(M'h•r, M'wer)] or the letter "Q' (quiet, no I Use of'trade names is for descriptive purposes only and does not constitute endorsement by the USGS. 4 C - A .50 M 35.60 25 60 7!CAII00O2 0ai W11 J ~ * M. c 1[.0 , 0 2-0 S wag < 3-0 :PI0JA " t * O 0 30me(MO0 -1.L0v-roqr • 0 Ot Figure 2.-'Earthquake epicenters in the southern Great Basin, 1991. Symbol sizes are keyed to event ML. " M 'A earthquakes detected) per 7k-minute by 71-minute topographic quadrangle in the central part of the SGB. This figure indicites where natural seismic energy release was highest in the SGB for 1991, since energy release is dominated by the largest magnitude event in each quadrangle. The SGBSN is a high-gain, low-dynamic.range network, consequently, for those earthquakes having magnitude > 2.7, most SGBSN seismograms are usually saturated for several seconds 'following the P- and S-wave arrivals. Only the lowest gain, horizontal-component stations, LSME and LSMN, are expected to record such events on-scale. Thus, ground-vibration amplitudes for many of the SGB's larger earthquakes (MrL > 2.7) are undersampled by the local network, and magnitude estimates for those earthquakes may be biased. For example, ground motion from possibly the largest SGB earthquake for 1991, occurring on March 10 in the southwestern Pahranagat Shear Zone of Nevada, was recorded on-scale only at the lowest-gain SGBSN staticns. Although the ML 4.07 determined from seismogram amplitudes at LSME and LSMIN is comparable to ML. 4.0 estimated by the Berkeley Seismograph Laboratory, Berkeley's estimate may be high as a result of its using a California seismic attenuation curve for path corrections from all sources, rather than a lower rate SGB attenuation curve for SGB sources (Rogers and others, 1987a). Possible SGB earthquake magnitude bias is further discussed in Harmsen and Bufe (1992). Magnitude estimates such a, M,. (Johnson, 1979) "re included in the hypocenter listing because potentially they could provide'a useful .- timate of earthquake size from saturated seismograms.. The practical limitatiozi of such estim'ates is that they must be calibrated against theoamplitude/period magnitude, ML,'in the magnitude range of importance. Such a calibration has only been performed for earthquakes having ML < 2.T-for SGBSN data (Rogers and others, 1987b), and we believe ýM.• and Md, as reported here, are biased low relative to the true magnitude for events having Mr.> 2.7., Hypocenter estimates are always approximate. Errors result from misidentified seismic phases (for example, the converted SP phase), from a-sumptions about crustal velocity struc ture, and from network geometry and other data limitations. Standard errors of hypocenter parameters are routiniely calculatdl •.V HYPO71 (Lee and Lair, 1975), and some of these are listed in Appendix A. Table I surmmarizes some hypoce'n're. parameter distribution statistics computed by HYPO71 for the digitally recorded SGB earthquake data of 1991. In table 1, RMS is the average traveltime residual, # P+S phases is the number of arrival time phases used by HYPO71 (i.e., tLose having weight > 0), Gap ii the maximum azimuthal angle without a station, Depth is the depth of focus estimate, Err(z) is the estimate of standard error in depth, and A,,,i, is the minimum source-to-station epicentral distance. Table 1. Selected statistical characteristics of a subset of the 1991 SGBSN earthquake catalog. 1 Statistic RMS # P+S M,. M P VfD Vh jJWZ` Gap Depth' Err(z) AmiR (_ec) Phases I I__ (deg.) (kin), (kin) (km) Mean- . 0.134 12.8 1.42 1.63 1.13 1.43 1.22 159 5.27 2.3 14.1 Median 0.13 12 1.34 1.60 1.14 1.34 1.21 142 5.04 1.4 12.3 Maximum 0.81 58 3.38 3.30 2.58 4.073 2.78 322 22.2 28.5 106.0 Minimum 0.02 5 0.68 0.70 0.15 0.06 0.05 36 -1.84 0.1 1.0 Quartile 3 0.16 15 1.60 1.90 1.50 1.63. 1.47 203'- 7.71- 2.9 17.5 Quartile 1 0.09 10 1.15 1.40 0.58 1.12 0.93 1ll 2.10 0.9 7.1 N# obs. 892 892 854 1 531 17 569 878 892 863 863 892 1 Only events captured by digital computer monitoring system are included. Also, only those hypocenters having the property, 0 6 1160 115.50 115c 114.75 118 0 117.500, ,- - 117.0* I 116.500. V I 1 3&.250 1o1.0 00.9 1.5 0s+0 - 380 S0oo o0o o 0 +o1 .s0 0 0 0 3. .+0 0 1.2 0 0 0 0 0 0 2.7 0 0 .1.9.9 0 0 0 a .. 0 a0 1. a 0 1.9 0 0 0 1.1 0 0 0 1.7 1.2 0 ' 0 0 1.7 1.2 0 0 0 0 0 1.U1.1l1.3 0 -1.9 0 1.0 0 1.5 1.6 0 a 0 1.2 0 -3 0 0 .0 1.1 0 0 1.0 0 0 1.0 1.0 -37.50 1 1.3 1.9 0 1.1 1.5 1.7 0 0 0 1.3 2.1 :. 1.5 0 0 2.6 0 1.7 1.7 2.5 2.0 3.9 1.2 1.3 1. 1.6 0 1.3 0 0 1.89 0 , 1. .1.50.9 1.3 0 0 0 1.2 2.7 1., 2.1 1.5 2.9 2. .92.1 • 1.1! 2.1 3.3 1.7 1.8" •1.6 - It 1.7NEVADA 2.6 1.62. 0 0 1.9 0 0 2.7 2.3 1.SIs 1.5 1.5 0 2.2 1 1.5 1.8 3.4 1.0 1.q 1.0 1 % 1.7 1.8 1.6 1. 1.8 0 1.8 0 0 4.1 3.6 1.9 "TEST SITE+L 1.7 0 0 1.9 0 a '.0 8.9 1.1 0. 13 1.5 1.2 1.8+0 0 C.6 0 0 0 0 0 +0 37 0 1.'- 3.G 1.6 2.1 1.9 0 0 1.2 0 1.3 1.5 2.9 1. 1.3 0 9.8 1.5 1.5 0 0 0 1.7 0 0 0 1.4 2.6 1.7 0 0 0 1 6 1.9 3.9 1.% 2. .1.0 2.6 1.3 0 0 0 0 0 0 0 0 0 2.5 2.1 1.5 0 0 1.7 . 1.5 1.2 1 .6 1.1 2.3 1.8 1.4 0 1.9 0 0 0 0 36.500 0 0 1.1 1.2 0 0 1.7 1.60 0 1.-- :.:.7 0 1.3 1.3 1.0 0 0 0 S0 0 1.2 0 0 1.30 0 0 0 1.2. 0 0 0 0 0 0, 0230 2.61.41.10 2.4 0 0 0 1.7 0 0 0 0 0 0 0 1.2 1. 0 0 0 0 1.2 1.6 0 0 0 1.8 .36 ,~~~C PMYCiMn y M *t'cca - t . SE MOGR APH STATION 0 25 50 100km ______.,______.1mum lnagnnitude/qU adrflc*e Figure 3.- Maximum earthquake magnitude per 71-minute by 7 4-minute quadrangle in the interior 2:of the SGB for-earthquakes of 1991. The letter Q represents a quiet quadrangle (no seismicity detected). 7 1:5. Defining magnitude for the ith event as avg(ML,., M '),t the average magnitude for digitally recorded SGB earthquakes in the 1991 catalog is about 1.3. Ninety-five percent of those earthquakes have ML < 2.4, and one-half of them are in the range 1 _< Mr. :5 1.8. Estimated depths-of-focus range from the earth's surface to about 22 km below sealevel, with 99% of earthquake hypocenters being less than 15 km below sealevel. (The depth estimates of the deepest SGB hypocenters from the 1991 catalog are unreliable.) SEISMICITY OF SELECTED AREAS IN 1991 Yucca Mountain Area No earthquakes were detected within 5 km of the potential nuclear-waste repository site at Yucca Mountain in 1991. Earthquakes in the Yucca Mountain area are located by using the Yucca Mountain -crustal'velocity model shown in Appendix F, figure Fib..The epicenters of the nearest-to-site earthquakes for 1991, shown in figure 4, are approximately colocated in the resurgent dome of the Claim Canyon Cauldron segment of the Timber Mountain caldera complex (Bye'r and others,' 1989). If the standard SGB velocity model (figure Fla; this model is used for sources away from Yucca Mountain) is used, the epicenter- of those earthquakes are 2 km northwest of those presented here, farther from the site. Hypocenter parameters for the 1991 earthquakes in the Claim Canyon Cauldron are summarized in table 2. (Seismograms for these earthquakes are available only on Develocorder film; the seismic computer was not operating at the time of their o'ccurrence.' Dita quality was tiadequate for focal mechanism determination.) The epicenters of all earthquakes in the western NTS region for the previous -: period of monitoring by the SGBSN, August 1978 through December 1990, are shown in figure 5. Although epicenters in the vicinity of Yucca Mountain could be presented on a fault map, it is diCcult to associate many of them with specific faults, due to relatively high fault density, C unknown fault dip from the surface to seismogenic depths, and to hypocenter errors. Caldera boundaries, especially thoee of Timber Mountain and its resurgent dome, may play a significant role in the control of local seismicity in the Southwestern Nevada Volcanic Field. Much of the seismicity in the Silent Canyon Caldera is associated with the nuclear testing program, however. Table 2. Summary of "relirmzinarylocation parameters for three earthquakes located in the Claim Canyon Cauldron segment north of Yucca Mountain, Nevada, in 1991. "Distance to site' represents the epicentral distance estimate to the point 36*51'N., 116'27.5'W., near the center of a poten tial nuclear-waste repository. Depth is relative to sealevel (0.0 kin). Sdx, sdy, and adz are HYPOT1 standard errors in estimates of hypocenter longitude, latitude, and depth of f•cus, respectively. MD is duration magnitude (Rogers and others, 1987b). j! DATE TIME LAT., LONG., N-S sdy' E-W sdx Depth±sdr MD Dist. to (UTC) a N: 0 W. (km) ) (k (kin) site (kin) 1991-12-17 05:14:49.7 36.942 116.467 0.2 0.2 3.3±0.3 0.71 10.2 1991-12-15 16:15:22.7 36.948 116.473 -0.4, 0.4 - 4.7±0.3 0.77 11.0 1991-12-15 10:51:57.3 36.959 116.477 0.4 0.4 4.9±1.0 1.05 12.2 "BareMountain Area Bare Mountain, unlike Yucca Mountain, has several active mines, with the resulting po tential problem of discrimination between natural and manmade seismicity. Earthquakes at Bare Mountain are distinguished from chemical explosions by considering event origin times and individual station seismogram waveforms. Seismograms from Bare Mountain earthquakes generally have sharper P-wave onsets than blast seismograms, with dilatational polarities at 8 4 2 RepositoryOPotenti'al I 7 SEISMOCRAPH STATION 0 CITY OR TO ImN 0 5 Ian o mag < 1.0 0 2.0 S mag < 3.0 o 1.0 : mag < 2.0 0 3.0 S mat - L*'-. near the volcanic caldera complexes of 4.- Seismicity ard focal mechanisms for earthquakes - Figure Caldera, 1991. Major calderas are labeled: BMC is Black Mountain - western l4vacda Test "Sitsfor of the Timber Mountain caldera. Caldera boundaries S*• " CCCS is Claini Canyon Cauldron'segmennt written comxun.). dashei where uncertain '(W. J. Carr, 1991, 9 M 195 I, .- ., 37.5" C 'I I I; -- ,r,115.25 ]n38.•5 7 SEISMOGRAPIL STATION 0 CrT OR TOWN 0 2 5 10O I I I I o me& < 1.0 0 2.0 S mag < 3.0 O 1.0 S mrg < 2.0 Q 3.0 S mag CCCS-Clalm Canyon Cauldron Segment BMC-Black Mountain Caldera Figure 5.- Seismicity at and near the volcanic calder" complexes of western Nevada Test Site for the period August 1978 through December 1990. Circled Cluster label-e "A' coincides with a mine on the eastern side of Bare Mountain, and may include some blast epicenters. Circled cluster *B" coincides with the Bond Gold Mine at Ladd Mountain, and circled clu-stier 'C' coincides with the Gold Bar Mine, Bullfrog Hills. Both of these clusters probably include several blast epicenters. t 10 16 C I- I stations having northeast and southwest azimuths from Bare Mountain, especially stations TMBR and YMTS. Blasts tend to generate large-amplitude Rayleigh phase on vertical component seismograms; earthquakes do not. Bare Mountain blasts sometimes generate a high amplitude, air-coupled Rayleigh wave, traveling at about 0.3 to 0.4 km/sec, evident on some Yucca Mountain station-seismograms (Rogers and others, 1987b, their fig. D1). This phase is absent from SGB earthquake seismograms. In spite of our efforts to properly categorize events at Bare Mountain, some of the "naturali seismicity is located near active mines, and the possibility exists that a few or the smaller events designated as earthquakes,!probable blasts, or blasts on the eastern flank of Bare Mountain have been misidentified in the listings of Appendixes A and B. Also, some of the hypocenters in the Bullfrog Hills west of Bare Mountain for earlier years of SGBSN operation, especially before 1987, may correspond to blasts at Ladd Mountain and at the Gold Bar Mine (see fig. 6). There is also limited natural (or mining induced?) seisrnicity at Ladd Mountain. These points are belabored because SGBSN data indicate that a fault in the immediate vicinity of the Beatty scarp (approximate coordinates, 36.880 to 36.90 N., 116.75' W.) is seismo genic. Swadley and others (1988) and Harding (1988) state that the Beatty scarp, a prominent Quaternary scarp, is a fluvial feature having no discer:"ble txpreasion in seismic reflection or refraction survey data. In 1991, six earthquake epicenters lay within 2 km of this erosional scarp. The scarp's trace and 1991 seismicity in its vicinity are shown in figure 6, just southeast of Beatty, Nev. None of those earthquakes were large enough for focal mechanism determination (maximum magnitude ML 1.2, on August 1, 1991, 18:38:33 UTC); however, P-wave polarity data are consistent with right lateral strike slip on a north-trending fault. The P-wave data are also consistent with normal slip on a northeast-trending fault. The SGB seismicity catalcg for 1978 throug'h 1990 (fig. 5) also indicates activity near the Beatty scarp (also see Harmsen, 1991, region is coincident with the Oasis Valley seismic lineament I his fig. 8). Seismicity in the Beatty (OVSL) (A. hi. Rogers and others, USGS, 1989, written commun.) that extends in excess oi 50 km in a north-south direction, at the western edge of the southwestern Nevada volcanic field. Although the OVSL might represent a fault zone, it may only be a zone of local stress concentration or of relatively elevated fluid pore pressure at the western boundary of several calderas. The north-south trend of the OVSL'may be due to relative absence of seismicity in the western one-half of Timber Mountain caldera rather than to activity on-a potentially important north-soutb fault. SDuring the first phase of the SGB network upgrade in 1992, Bare Mountain as well as Yucca Mountain will be more densely instrumented. With an upgraded network, it is likely that well constrained focal mechanisms from earthquakes in the Bare Mountain area can be determined. SSeismicity in northwestern Bare Mountain occurs within a kilometer or so of an inferred de tachment fault with surface trace believed to lie at the western base of Bare Mount'dn. The detachment was most recently active about 11 million years ago (Hamilton, 1988). Thus, the possibility exists that denser seismic instrumentation may shed light on seismicity beneath a possible detachment fault. Death Valley - Furnace Creek "The west side of Death Valley, two km north of Stovepipe Wells, Calif., experienced an earthquake swarm (about 36 eartbquakcs detected) that began in May, 1991, with maximum Smagnitude of 2.6, and continued into late September. Figure 6 shows the epicenters and the pre -focal mechanism for the largest earthquake of that series. The focal mechanism displays dominantly right lateral strike slip on a northwest trending, steeply dipping nodal plane, or predominantly left lateral strike slip on a northe"t trending'nodal plane. The west-directed tension axis of this earthquake's focal mechanism is similar to those of other focal mechanisms 11 .1 . ., , " -Y. *-~' V, 93 117" 116.5 --- 37" Qj 36.5 -'79 C 36 116.5 li V SEISMOGRAPH S¶I 'ATION 0 10 20 30 km I0 CITY OR TOWN DP-Darwin Plateau o mag < 1.0 0 2.0 ;5 mag < 3.0 o 1.0 - mag < 2.0 0 3.0 9' mag, Figure 6.- Earthquake epicenters in the vicinity of Deith Valley, California, for 1991, and faults that may. have had surface movement in the last two to three million years. Focal mechanism in swarm west'of Stovepipe Wells, California, With compressional quadrant darkened, is for an earthquake of May 15, 1991, 20:01 UTC. Focal mechanism with'sub-hbrizontal nodal plane is for an earthquake of April' 13, 1991, 16:06 UTC, in the Amargosa Desert, California. 12 I R in its vicinity, for example, that of the Stovepipe Wells earthquake on July 8, 1986 (Harmsen and Rogers, 1987). A known Quaternary fault strikes northeast along the north end of Tucki Mountain, just south of Stovepipe Wells, and probably dips towards the epicenters (fig. 6). At the estimated focal depth of 6.75 kin, the May'15, 1991, earthquake, whose northeast-striking nodal plane has 670 -200 dip, may be an example of seismicity on this fault: SSGBSN focal mechanism data generally support the hypothesis that a counterclockwise "rotation'ofprincipal horizontal stress directions occurs from Utah and the eastern part of the SGBSN to the western part of the network and the Sierra Nevada boundary zone. Further "evidence 6f a nearly east-wcst minimum compressive strews direction in this part of the SGB is provided by analysis of slickensides in Neogene rocks from Darwin Plateau, about 50 km southwest of Furnace Creek'fault (Schweig, 1989). Schweig found, when inverting his best slip data for a plausible fixed-direction lo" stress tensor, that S3 -r Sh has azimuth N87"W S870E, anld that S3 * SH has magnitude comparable to S, v Sv. If such a stress field exists at seismogenic depths in Death Valley, then the Furnace Creek fault is favorably oriented for right lateral strike slip. Seisrlnicity continues to be conspicuously absent along the traces of the Furnace Creek and the Death Valley faults (fig. 6) as often noted in discu-9ionr of SGB seismicity, most recently in the 1990 seismicity 'report (Harosen, 1991). Whether that fault system pxisents a significant seismic hazard is conjectural because little is known about its seismic coupling, i.e., whether ' asejiric or seismic slip' is primarily responsible for re'leving extensional strain at Death Valley. "The paleoseismic record of faulting along'much of the-Death Valley-Furnace Creek system indicates it is a significant earthquake hazard. Hamilton (1988, p. 72) contends that the Death Valley region is now being widened, and that the Death Valley and Furnace Creek faults define the eastern limit of current 'deformation. Amargosa Desert E Two of the most active parts of the Amargoaa Desert south to southwest of Yucca Moun tain, Nevada, during the SGBSN monitoring period (August i978 to present), are the California, Nevada border region and Fortymile Wash. A third active sub-region of the Amargosa Desert occurs about 5 km west-southwest of Amargosa Valley, Nev. Like the Fortymile Wash seismicity, "these earthquakes occur within the Spotted Range-Mine Mountain structural zone (Carr, 1984), a wide zone of predominantly northeast-striking, seismically active faults with a history of left lateral slip. Amargosa Desert state-border-vicinity seismicity for 1991 is shon 'in figure 6, along with a focal mechanism for a ML 1.3 earthquake on April 13, 1991. This earthquake's P-wave first motions were dilatation-, (down) at consecutive SGBSN st'ationi over a wide range (> 2000) of source-to-station azimuths, a response" that would be observed if slip were occurring on a sub-horizontal fault plane. Indeed, all focal mechanism solutions for the hypocenter at 4.8 km display a sub-horizontal nodal plFane'(two such solutions are shown in Appendix D, fig. D5). "Because double-couple focal mechanisms baringa sub-horizontal nodal planý'necessarily have & sub-vertical 'n6dal plane, _ad neither nodal plane is mechanically preferred, it is not inferred that seismic slip ox a dctachmcent fault is evident in SGBSN data; however, focal mechanism solutions displaying a sub-horizontal nodal plane for earthqiuake in other parts of the SGB are also presented in the 1987 through'1989 seismicity report (Hirnen and Bufe, 1992). -Another zone'6f recurrent seismicity in the Arniargosa Desert is in the irimmediate vicinity of Fortymile Wash, labeled in figures 4 and 5, in the Lathrop Wells, Nevada, geologic quadrangle, about 15 km south of the site of a potential high-level nudear-waste repository at Yucca Moun tain, Nevada. A'swarm of ablout 20 earth4uakes occurred there beginningjin January 1991, with the largest event (ML, 1.5) on January 5, displaying a strike.slip focal mechanism solution (fig. 13 I 4, mechanism labeled OP). The northeast-trending slip nodal plane agrees in strike and left-lateral sense with many faults mapped in thi Spotted Range-Mine Mountain structural zone 1984). (Carr, Pahranagat Shear Zone Pahranagat Shear Zone (PSZ) is a major northeast trending, leftlateral shear zone south and southeast of located Alamo, Nov., having ielatively elevated seismicity'rates. - seismicity of'1991 at Pahransgat Shear Zone A map of the A and vicinity .vith some local prominent faults is shown in figure 7. The largest SGB earthquake for 1991, Mr 4.1, was the mainshock of the series labeled 'A* in'figure 7. Focal mechaiisnis for the mainshock (March 10, 1991, 21:38-48 UTC)-and one of the largest aftershocks a focal mechanism (April 15, 1991)'ar'e also shown, along for &ML 3.6 earthquake to the east of seres with UTC). A (November 7, 1991, 2:17:37 No felt rep'orts1 for these or'other s5GB earthquakes of 1991 are on record with NEIC, although two dozen public agencies were canvassed SU.S.' earthluaikes about the rainshock.' Inasmuch as in this magitude range near a western town or city are usually reported as felt, the probable explanation for the 'unfelt t reports following PSZ earthquakes is that local have been 'desensitised* by frequent residents sonic disturbarces by jet aircraft from Nellis Base maneuvering Air Force at low altitudes near Alamo and Hiko, Nov. (NEX staff and Dý rf, USGS, oral comrnun.). E. Overtu Seismicity migrates with time at PSZ, with clear chang esin concentrations visible over 2-year intervals. of activity being Series A is in a location having little by the SGBSN. pr'evious seismicity recorded Figure 8 shoa;s in map view the seismicity thro'gh 1990." of the PSZ for the period 1984 Rogers and others (1987b) discuss PSZ seismicity 1983, and attempt for the period 1978 through t6odecide whether it is more likely that secondary, north-trending the northeast-trending faults or the faults are currently more active (see their years of seismicity Figurie 15). An additional 8 data do not resolve this issue. The other and '(;' two PSZ series for 1991, labeled OB" in figure 7, are at locations that have experienced The nearby earthquakes in previous years. spatial centroid of seismicity in those two series migrates with time. Las Vegas Valley Earthquakes The Lai Vegas Valley- shear zone is considered Spring to be the northeastern boundary of the Mountainasblock of'the Walker Lane belt northwest-trending (Stewart, 1988). If presently active, major faults in the Las Vegas Valley would be expected to experience right slip. SGBSN seismicity in Las Vegas Valley has the cioncealed right-lateral Las Vegas been limited and has been difficult to asscciate Valley fault zone in the central part of Las with . Carlson, 1978)abecaud Vegas Valley epicenter lineations in the valley are apt perpendicular to trend northeast, to' the fault trace (see Rogers and others, Figure 9 shows 1987b).. the seismicity of much of the Las Vegas Valley 1991, and vicinity for the year * along with major range front faults and A' spatially diffuse series of -the infirred trace of the Las Vegas Ve.Jley fault. 33 earthquakes occurred in'a previously seismically 3 to 6 quiet area about km north'of the'town of Indian Springs, Nevada, during June and July of 1991. In the center of that series, SGBSN recorded on March 1,1991, an isolated : mechanisAm solutions for the ML 2.3 foreshock. Focal March 1 foreshock and the July 12 16:41 UCT Indian Spring 'series; which had-ML 2.6, are mainshock of the also shown in figure 9 and, with greater detail, Appendix D. Figure 10 disp!zys the seismicity in of the'same region for the period 1984 through In this context, a 'felt report' means that at least one person responded to the NEIC survey that the earthquake was felt in his/her comnmunity. o! 14 IC -. .SS. *S'* .% ." * . ,..... * ' 4.- 3 S.-. 4, .0' +.y. S *" -''I 1sot 37.526B 0 C@ o V So 0 0 0a )-AB'JO 0 VICe Ire, I ~ 6U " - *1 I 1 36.914 115.367* 114.565 =: k V SEISMOGRAPH STATION 0 CITY OR TOWN 0 5 10ikm 1 ,LI J • Mag < 1.0 o 2.0 ig mag < 3.0 o 1.0 ; mag < 2.0 o 3.0 9 meg Figure 7.- Preliminary epicenters and focal mechanisms for the larger earthquakes of 1991 in the vicinity of Pahranagat Shear Zone, Nevada. Major faults shown include range front faults and others known or suspected to have had surface movement in the last 2-3 million years. 15 0 ;21 Sq J ¾ I. -, 1. 1984-1990 37.526 i I I 11. I. 'C !ii 115.367 35.914 114.565 V SEISMOGRAPH I0 , 5I 1Okm STATION 0 CITY OR TOWN . mag < 1.0 o 2.0 9 mag < 3.0 0 1.0 _ mag < 2.0 0 3.0 5 mag Figure 8.- Seismicity fur the same region as in figure 7 for the period 1984-90. 16 ,,,V C 1990. Rogers and others (1987b) discuss the geologic framework of that region and its seismicity for the period August 1978 through 1983. As is observed in many other parts of the SGB, the majority of the local seismicity in the vicinity of Las Vegas Valley cannot be directly associated either with the main fault or with range-front faults. Most small (ML < 4.5) local earthquakes recorded during any given year by SGBSN nucleate on splays and other features secondary to the main faults of the SGB. This phenomenon has been partially modeled (in' two di neinsiozi) as a seismic response to shear strain buildup away from7 zero-strength major faults that have moved, thereby perturbing an otherwise uniform strain field (Gomberg, 1991). SGB EARTHQUAKE FOCAL MECHANISMS FOR 1991 Preliminary focal mechanism solutions for 14 SGB earthquakes of 1991 having ML >_ 1.4 are shown in figure 11 (the focal mechanism for a MLO.8 earthquake at northern Crater Flat is shown in fig. 4), and focal mechanism parameters are listed in table 3. The individual solutions are shown with SGBSN P-wave station polarity information and with alternate solutions in Appendix D of this report. An *alternate solution' is defined as one in which there are an equal number of polarity inconsistencies (usually 0) as In the preferred solution; however, alternate solution nodal planes may narrowly miss intersecting impulsive polarity points, where P-wave amplitudes from a point-source dislocation would be expected to be null (thus, the word "nodal"). Seismograms from which polarity interpretations are derived are stored on magnetic archive tapes by the SGBSN. Paper records of r 10 seconds of data surrounding each station's P-arrival are available to investigators when requests for such data are approved by USGS-Yucca Mountain Project Management. Focal mechanism solution P- and T- axes fo'r the M1, > 1.4 earthquakes listed in table 3 are plotted in figure 12, along with average P and T azimuths. For these data, the average tension axis has azimuth N.57.2°W. and plunge 0 30 (using Watson statistics, Schuenemeyer and others, 1972), and the average pressure axis has azimuth N.34°E. and plunge 17°. Co'mpressional quad rants of those 14 focal mechanism solutions are intersected, as are tension quadrants, and the resulting regions of intersection, projected onto the lower focal hemisphere, are shown in figure 13. If one assumes that the directions of principal compiessive stresses, a, (maximum) and us (minimum), in the portion of the earth's seismogenic crust sampled-by a-set of earthquakes are constant, then the intersected dilatational quadrants (containing focal mechanism P-axes) and compressional quadrants (containing focal mechanism T-axes) of those solutions must also con rain the directions of the regional a, and as axes, respectively (Angelier, 1979). In figure 13, ua is contained in the (azimuth, inclination) patches covered with x symbols, and us is contained in the patches covered with o symbols, assuming such a constant stress field. Thus, when using '-"the focal mechanism data of 1991, one infersthat 2850 5< azimuth(us) :_ 320%, av estimate 0whose bounds could be tightened by including focal mechanism data of previous years. One also infers that 10°, ;• inclination(al) :5 40°, showing that SGBSN focal mechanism data tend to reject the hypothesis that, for the region as a whole, the maximum compressive stress direction is nearly vertical (however, for some parts of the SGB, normal slip nMay be the dominant form of deformation =•one such4subregion contains Gold Mountain, the' Palmett6 Mountains and the Montezuma Raiige 'see figure 1). Patfches of tl~e lower focal hemisphere where*all but one and all but two of the focal mechiahisri compressional (respectively', dilatational) quadrants intersect are also shown in figure 13. SGBSN focal mechanism solutions for earthquake data of 1991 are generally similar to solutions for previous years, reported in Rogers and others (1981, 1983 and 1987b), Harmsen and Rogers (1987), Harmsen (1991), and Harmsen and Bufe (1992). When using regional network P-wave polarity data to determine the earthquake focal mechanism, it is known that solutions are often sensitive to the assumed focal depth, a point K] 17 I .A.' * 7. .7.' t 1991 } 37.32" I / 3 -4 o -P 0o L) SLL 0 A. :;4 CHMAN , 0 Cs a 0 3 U 06% 0 0 / w V . aO ( V - *1Q .. 4. -V, V I1oe .I . .. 115.052 v SEISMOGRAPH STATION ".0 10 20 30 km 0 CITY OR TOWN " mag< 1.0 0 2.0 : mag <3.0 YF-Yucca Flat (NTS) 0 1.0 9 mag < 2.0 0 3.0 1- mir g Figure 9.- Seiznicity recorded in,the vicinity of La. Vegas Valley, Nevada, and Nellis Air Force Range east of NTS for 1991, with two focal mechanisms for earthquakes from a swarm 5km imorth of Indian" Springs, Nevada, plotted near their corresponding epicentera. 'L" epicenters are for low-frequency events associated with nudear' device tests at Yucca Flat. 18, ,I" i. UI 1984-1990 37.32 00 o o0 0 04 0 0 0 01 o ICHMAN JbCCO -" EN 00 •. ' Ocit 0 0 ":11 00 m c~Eo~o so P..0 Il S." ""J 36.286 116 115.052 V SEISMOGRAPH STATION .0 CITY OR TOWN 0 1o 20 30 km_ I I I I • m j n o 2.0 ;5 mag < 3.0 0 1.0 9 Mag < C2.0 0 3.0 !n mag Figure 10.-Seisi-city recorded in the vicinitY Of Las Vegas Valley, Nevada, and Nellis Air Force Range east of NTS for'the period 1984 tihrough 1990. 19 I 25 Table 3. Preliminary southern Great Basin earthquake focal mechanisms for 1991. OT., eart.hquakc origin time- St, strike of nodalpla3re Dp, dip of nodal plane; Rk, rake ofslip vector, Tr, trend of axis PI, plunge of axis. Angles are rounded to thA nearest degree. ML, local (SGB) magnitude. All 1991 foLal mechanism solutions are derived from single events. Nodal planes: No inferred fault planes for these focal mechanisms are presented here, although for many of the mechanisms, inferences about the preferred nodal plane based on lineations of epicenters and/or on the state of tectonic crustal stre"s are possible. For example, if the maximum horizontal compressional stress is oriented at about North 20' to 300 East, then right-lateral strike slip may be expected on steeply dipping, north-trending fault planes with greater likelihood than left-lateral strike slip -n east-trendinj fault planes, other mechanical conditions being equal. Rmk:ý Remaxrk, An * in this column means that (SVIP), amplitude ratios were used to constrain the focal mechanism. Rather than including uncertainty estimates for strike, dip, and rake in this table, we show alternate solutions in the figures of Appendix D as dashed-line nodal planes. For most of the focal mechanisms listed below, the uncertaintiei in dip and rake angles are about ±10%, and uncertainty in nodal plane strike is about "5". Focal mechanism solutions baued on aource-to-.tation rays from ixed-depth hypocenters are indicated by a I next to the focal depth listed below. Focal mechanism solutions for alternate, competing hypocenters are considered for the earthquake of November 7, 1991, 02:47:13 UTC (shown in Appendix D, Figures DIS and Di1). Focal Quadrangle Name I/odaJ'planes 1 rincipal axes U Figure QT. (UTI Lat. Long. depth Mag. • or other aSt 2nd P TI. B m Index Date Time 'N 'W (kin) (ML) Geographic ID St Dp Rk St Dp Rk Tr PI Tr Pl Tr Pl k DI 910105 8:55 30.730 116.432 7.55 1.5 LATHROP WELLS NW 154. 88. -165. 64. 75. .2., 20. 12. 288. 9. 162. 75. D2 910301 17:24 36.831 115.644 1.11 2.3 INDIAN SPRINGS NW 231. 46. 27. 122. 71. 133. 182. 15. 75. 46. 285. 40. D3 910310 21:38 37.118 115.227 8.11 4.1 LOWER PAURAN. LAKE SW 82. 78. .-21. 1-7. 70. .165. 39. 25. 131. 4. 230. 65. D4 910312 13:54 36.939 118.594 6.95 0.8 CRATER FLAT 111. 82. .55. 212 '38 .166 57 39 171 26 284 40 DS 910413 16:08 36.488 116.575 4.80 1.3 - RYAN 260. 10. 0. 170. 90. 100. 250 44. 90. 44. 350. 10. D6 910415 6:53 {37.121 115.211 3.79 3.1 LOWER PAHRAN. LAKE SW 67. 80. .39. lC4. 52. -168. 18. 34. 121. 19. 235. 50. D7 910515 20:01 36.830 117.151 6.75 2.6 STOVEPIPE WELLS 319. 72. -156. 221. 67., -20. 181. 30. 89. 3. 354. 60. 0 D8 910608 14:58 37.103 116.998 6.31 3.4 SPRINGDALE, 190. 74. .143. 87. 55. .20. 54. 37. 315. 12. 210. 50. D9 910612 22:39 37.192 118.956 6.0' 3.3 SPRINGDALE' 91. 77. .38. 183. 52. .177. 44.' 36. 145. 16. 255. 50. D10 910614 6:24.36.739 115.986 2.0' 2.2 MERCURY ' 345. 81. 120. 89. 32. 17. 51. 30. 286. 45. 160. 30. .€ D11 910618 22:59 37.114 118.446 9.03 1.4 TIMBER MTN. 192. 80. -152. 97. 62. -11. -58. 27. 322. 12. 209. 60. D12 910704 0:22 38.997 116.421 7.67 1.4 TOPOPAH SPRING NW 105. 87. -4. 195. 86. -177. 60. 5. 150. 1. 255. 85. D13 910712 16:41 36.636 115.641 1.29 2.6 INDIAN SPRINGS NW 245. 87. 10. 155. 80. 177. 20. 5. 110. 9. 260. 80. D14 910805 11:40 37.180 117.414 5.71 3.0 GOLD MTN. 45. 60. .90. 225. 30D .90. 315. 75.'135. 15. 45. 0. DIS 911107 2:47 37.089 115.088 7.39 3.6 LOWER PAIIRAN. LAKE SE 343. 68. 145. 87. 58. 28. 37. 6. 302. 39. 135. 50. D16 911107 2:47 37.096 115.106 9.5' 3.6 LOWER PAHRAN.'LAKE SE 332. 48. 125. 106. 54. 59. 217. 5. 317. 65. 125. 25. D17 911130 6:45 38.739 116.215 5.58 3.0 SPECTER RANGE NW 344. 63. .142. 235. 57. -33. 202. 45. 109. 4. 15. 45. I' &*4 - 177 -A ~ .Tjft -Do t ~titLi - 00 ~' 4 7 m Is , ý , .,. * I , '0 ý,j * -- -. S. L. ' - '.. -- - - - N I E ( :v.4 1991 SGB focal mechanisms ' .1 a P-axis 0 T-axis Figure 12.- Inclinations (plunges) and azimuths of 14 focal mechanism preferred solution P-axes and T-axes for SGB earthquakes of 1991 having ML > 1.4 (listed in table 3 and shown in rigure :1 11) are plotted on the equal-area lower hemisphere projection. The inward-directed tabs represent :1 the orientation of the average P-axis for those data, and the outward-directed tabs represent the orientation of the average T-&xis. Dashed circles represent inclinations of 25, 451, and 65*. i;: 22 ( 4 M Intersection of P & T Dihedra 1*XT 1 ' E S 1991 SGB focal mechanisms Number of mechanisms =14 ( 1 region 0 1 2 inconsistencies resp: x a 3 region 0 1 2 inconsistencies resp: / Min & max depths (kin) 1.0 9.0 Figure 13.- Intersection of cormpressional first motion quadrants, containing the T-axes of 14 of the 16 SGB focal mechanisms-of 1991, are shown with o symbols. Similarly, the iernsmction of "the14 focal inechanism dilatational quadrants, covtaining the P-axes, are shown- with x symbols. Regions where all but one and all but two compressional (respectively, dilatational) quadrants intersect are also highlighted, using different symbols. - 23 ) "1q demonstrated for selected SGBSN earthquake data in Harrsen and Bufe (1992). P- and S-wave arrival time data from stations near the seismic source ('near' means source-to-nearest-station distance < 1.5 focal depths) are necessary in most circumstances of-focus estimate. Because to reliably constrain the depth station spacing in the SGBSN is about 20 to 30 kim, such data are generally not available. In an attempt to quantify the uncertainty in focal depth beyond what I. is available from HYPO71's standard error in depth, which is often unrealistically small, I of root-mean-square graphs (RMS) traveltime residual (sec) versus fixed depth (kim) for hypocenters * corresponding to Appendix D'i focal mechanisms numbered D1, D2, D)6, D8, D11, D12, D13, *! DIS, DIG, and D17 are shown in figure 14. The RMS graph for an earthquake on December I0, 1987, whose focal mechanirn is reported in Harmsen and Bufe (1992), is also shown in figure 14, to indicate the similarity of its behavior to that of a nearby earthquake on November 30, 1991. Unfortunately, these graphs are not unique for a given arrival time data set and crustal model because,-a- discussed in Harmien and Bufe (1992), the RMS function is sensitive to the manner in which individual phase data are weighted in the hypocenter solution with respect to source to-station distance and azimuth; station residual, analyst'sasaignmhnt of data quality, and to - other factors deemed important. Figure 15 demonstrates that the graph of RMS may display a relatively well-defined minimum for a given data set when: a certain distance-weighting scheme is used, but a less wellefined minimum when arother equally plausible weighting scheme is . If used. Nevertheless, lJI such RMS graphs provide useful guides to hypocenter uncertainty. instances where a 5- to 10-km-deep hypocenter has about In those a,* the same traveltime- residual as a near-surface (sea level ±1 kin) hypocenter, caution needs to be exercised whcn using the focal mechanism data, for example, as input to computer programs that attempt to infer stress-field crustal properties from nodal plane and slip vector orientations. Depth-of-focus ambiguity may be reduced by increasing seismic station density near "*j zones and by improving source the velocity model used for locating aarthquakes, i.e., by incorporating t known iock properties, especially lateral velocity variations, into the earth model. Seismic properties of rock in the vicinity of Yucca Mountain and elsewhere in the SGB are actively being studied by several Yucca Mountain Project participants. CONCLUSIONS$ 9 The SGBSN computed hypocenters for 980 southern- Great Basin earthquakes recorded in 1991. The maximum magnitude for SGB earthquakes of 1991 was M .4.1. During the calendar year, 1 no SGB earthquake was reported to the NEIC as felt. * The Oasis Valley lineament continues to display limited seismicity along during 1991, including six its s, 50-km length events at northwestern Bare Mountain. This lineament may be more an artifact of the inactivity at the western part of the calderas of the southwestern Nevada volcanic field, which forms the eastern boundary of the lineament, rather than activity on a north-south fault or series of en echelon faults. * Within a radius of about 10 krm of a potential high-level nuclear-waste respository, the Yucca Mountain area experienced no earthquakes detectable by the SG]BN during 1991. Three t earthquakes, the largest Jill having magnitude 1.1, occurred just beyond that 10-km limit, in the Claim Canyon Cauldron segment of the Timber Mountain caldera complex. * The major Death Valley-Furnace Creek fault system is presently seismically inactive, although isolated earthquakes and swarms of earthquakes occurred during 1991 about 5 to 10 km west of the trace of Furnace Creek fault in Death Valley, Calif. Various lines of evidence suggest that the local crustal stress field has an approximate east-west minimum compressive stres direction, and maximum horizontal stress of sufficient amplitude to produce strike slip deformation at 24 1.4 LATHROP WELLS NV F - 910105 6 55 21 E- C 0 C Li r C3. X 4i "-* " 4: .0 .0 o)lt 5~m -0.8 00.8 Oelt• X~km) Fixed H (kin) .4 INDIAN SPRINGS NV 0 910301 17'24 58 0 E z o w 0- Z 02 1 , B 392 0 C B f., F -1.0 1 I i I I I I -0.0 0 0.2 Delta XA'km) Fixed H (kin) &Pha- 48 Gop-125" Dmin- 5.1 C LOWER PAHRANAGAT LAKE N'J c; km C 0.1- 010418 6 53 36 C C E 0- C 0 - 6 BB C wXL:J U3 4-" - ~A z O I B - **% 2 0 95 2 3 37 i -2.0 0 Fixed H kin -- 1.5 0 .5 Oelica X(km) Fixed" H (kin) epicenters for HYPO71 hypocenters for Figure 14. Left Side: Plot$ of fixed-depth and free-depth prepared. Symbols 0, 1, 2, ... , A, B, C, selected earthquakes for which focal mechanisms were at zero, one, two, ... , 10, 11, 12, ... D, E, F are epicenter positions for hypothetical hypocenters to the epicenter for the solution with depth below sea level (hexadecimal notation). M" refers free depth epicenters, with zo = 7 and 0 km, "fixid at 1 km above sea level. S' and "Z* refer to as a function of assumed depth of focus rsýpectively.' Right Side: Plots of RMS traveltime residual letters above the (z, y) points are 'grades" that corresponding to the same earthquake data. The frequently use such grades to assess the HYPOI assigns to the respective hypocenters. Anilysts reliability of hypocenter estimates. 25 31 - I...) N A -t A. It I I 0. SPRINGOALS8 1 I U 2. 910081 5 C R, I 0 w Ia *0 4 C 3 F I -0.0 0.3 Oelt. X(km) Fixed H (kin) 910018 22 59C 9 F Al7 cn 0 4 0 I. C. 1 0I. 2.0 Delta XtkmJ Fixed H (kmn) 0.1 TOPOPAH SPRING NW 0 910704 0 22 1 15 90 9A I 2 E0 W w CD 0 4 (X ii 3 C 3 F B0 0.0 D elta X(km) Fixed H (kin) 0.1 INOIAN SPRINGS NV 0- 910712 10 41 3% 1 E 0 A U)J 9 E 4 wr 0. F -1.3 1 1 j -0 .4 C 0.2 Oelta X(km) FixeddH(kmn) Floure 14 (contInued) 26 hII I - ~o. 2~~~~ ~ ~rninna .i~. toWI 2.0. ELOWER•911107 p'~PAHfAII.Vr%2 47 13 I I.nPr- QVI E C *4, B A Ln 4 C: a Z 2 41 3 "-1.3 I- ' I- I I I i M -.3 . . -0.D Xtkm g Delto• Xtkm) Fixed H (kin) 03 SPECTER RANGE NV g11130 8 45 50 hI -v 0 74 0 2 0 Iz 98 OZ5 ft w * .) DC Mn 0 CD E 3 -n n. .1'- I I I I I I I I I I "0.- 0 0.7i Delt• X(km) 0.4 SPECTER RANGE NV E 0 V71210 2 35 17 a I- - a 4. 9 s 9 M 0 L~A 0 ,00_ O 1:Lfl Nr- 3 IF I .1 a I I -0.85 m i 0.4 Delta- X(km) Fixed H (kin) Figure 14 (continued) 27 U J33 - - fl I:, .. . '- p -'.7.. ( I' (,.. LOWER PAHRANAGATFLAKE - uPh8- 57 Gep'124 mmn- 6. 910310 21 38 47 c; 0 C w 00 4 8 39 A tn, 0. 7 .0 -M 0 0 F CD 2:, M: 2 NN 3 0.7- -2.0 0 3.0 Delta X(km) Fixed H (kin) xPho- 40 Gop-136* Omit,- 6.8 C 0.4. LOWER PAHRANAGAT LAKE SW km .1 M10310 21 38 47 .1 .4 2 U., B E Ut U, C/- 0- 0 tt, U, C!C to-., d 0 ABC cn, 5 9 F 2 CccC CD cS 0 Al" 2 A 3 oD U ...... I i i "1 5I 31.5 i Delta X(km) Fixed H (kin) Figure 15. Same meaning of two sides as in figure 14. The upper pair or graphs is for the same earthqu'Ake Jata as the, lower'pair, only the manner in which arrival time data were weighed with respect to source-to-station distance is changed. Data from all SGBSN stations were used for upper graph. calculations, whereas stations greater than 110 km from the epicenter were zero weighted (excluded) for lower graph calculations. This plot demonstrates that a 'well-constrained' hypocenter is not entirely independent of the analyst's point Rf view- on howv phase data from stations relatively rar from the seismic source should be weighed in the locatiorn process. A1 A 28 I seismogenic depths. Thus, the Furnace Creek fault zone is favorably oriented for right lateral slip. * Boundaries of the southwest Nevada volcanic field calde"ra complexes with country rock are .zonesof earthquake activity in 1991, and previous years. This implies that'strength anisotropy, strews concentrationzs near material interfaces, or variations in fluid pore preswures at those "interfaces, or some mixture of these physical properties,play an important role in determining "theseismic response of the earth's crust to regional strains in the immediate vicinity of Yucca "Mountain. o Generally, focal mechanism solutions for small SGB earthquakes of 1991 display predomi 6 "niantly strike slip n steeply dippingi nodal planes.-Certain zones, such as the Gold Mountain, California-NeVada border, exhibit seismcaty having normal slip focal mechanisms. REFERENCES CITED Angelier, Jacques, 1979, Determination of the mean principal directions of stresse for a given fault population: Tictonophyics, v. 56, p.,T17-T26. (NNA.920512.0002) ByesF..,Jr, CrrW-J. ad rkd, Paul P., 1989, Volcanic Centers of Southwestern Nevada: Evolution of Understanding, 1960-1988, Joy-nal of Geophysical Researck, v. 94, p.ý 5908-5916: (NNA.900403.0407) Carr, W. J., 1984, Regional structural setting of Yucca Mountain, southwestern Nevada, and .late Cenozoic rates of tectonic activity in part of the southwesterii Great Basin, Nevada and "Clifora U.S.,Giological Survey Open.-Fil Report 84-854, 109 p. '(NNA.870325.0475) Gomberg, J. S., 1991, Seismicity and shear strain in the southern Great Bain of Nevada and California: Journal of Geophysical Research, v. 96, p. 16,383-16,400. (NNA.920211.0032) Hamilton, W. 13.; 1988, Detachment faulting in the Death Valley region, California aid Nevada, in Geologic and Hydrologic Investigations of a Potential Nuclear Waste Disposal Site at Yucca Mountain, Southern Nevada: U.S. Geological Survey Bulletin 1790, Michael D. Carr and James C. Yount, eds., p. 51-M5.(NNA.920211.0034)% "Harding,S. T., 1988, Preliminary results of high-resolution seismic-reflection surveys conducted across the Beatty and Crater Flat fault scarps, Nevada, in Geologid anTd Hydrologic Inves tigations of a Potential Nuclear Waste Disposal Site at Yucca Mountain, Southern Nevada, . Carr and Yount, eds. USGS Bulletin 1790, pp. 121-128."(NNA.920529.0053) Harrnsen, S. C., 1991, Seismicity and focal mechanisms for.the southern Great Basin of Nevada and California in 199C: U.S. :GeologicalSurvey Open-File Repori 91-367, 103 p. (NNA.920213.0219) Harmsen, S. C., and Bufe,-C. G., 1992, Seismicity and focal mechanisms in the southern.Great *- Basin of Nevada and California: 1987, through 1989: U.S. Geological Survey Open-File - 'Report 91-572, 216 p. (NNA.920408.0001) Harrnsen, S. C., Gomberg, J. S., aiid Richards, P.'G, 1991, Shallow seismicity following se . lected nuclear explosions at Nevada Test Site, abs., in Papers Presented at 13th Annual - PL/DARPA Seismic Research Symposium, p. 237-240. (NNA.920605.0067), Harmsen, S. C.,and Rogers, A:'M.; 1986, Inferences about the local stress field from focal mechanisms- applications to earthquakes in the s•hthern-Great Basin of Nevada: Seismo logical Society of America Bulletin, v. 76, p. -1560-1572. (NNA.920211.0035) "Harmmen, S.'C._,'a Rogers, A M., 1987,'Earthquake location data for the southern Great Basin "'-* ýof Nevada and California: 1984 through 1986: -U.S. Geological Survey Open-File Report 87 5,6, 92 p..(NNA.870821.0046), - 29 J A. • Hoffman, L. R., and Mooney, W. D., 1984, A seismic study of Yucca Mountain and Vicinity, southern Nevada; Data report and preliminary results: U.S. Geological Survey Open.File Report 83-588, 50 p. (HQS.880517.1267), - . Johnson, C. E., 1979, I. CEDAR: An approach to the computer automation of short-period local seismic networks. U. Seismotectonmics of the Imperial Valley of Southern California: Pasadena, California Institute of Technology Ph. D. dissertation, 332 p. (NNA.920605.0068) Kislinger, C., Bowman, J. R., and Koch, Karl, 1981, Procedures for computing focal mech• nims from local (SV/P), data: Seismological Society of America Bulletin, v. 71; p. 1719 1729. (NNA.920211.0036). - 1982, Errata to procedures for computing focal mechatnistms from local, (SV/P). data: Seismological Society of America Bulletin, y. 72., p. 344. (NNA.920211.0037) Lee, W. H. K., and Lahr, J. C., 1975, HYPO7I (revised): A computer program for determining hypocenter, magnitude, and first-motion pattern of local earthquakes: U.S. Geological Survey Opeis-Filc Report 75-311, 116 p.(NNA.920211.0038) Lee, W. H. K., aid'Stewart, S. W.,'1979, Principles and applications of microcartiquake net works- New Yorl• City, N. Y., Academic Press 293 p. (NNA.920)211.0039) Rogers, A. M.,. Harmsen,iS. C., and Cart, W. J., 1981, Southern Great Basin Seisimological Data Report for 1980 and Preliminary Data Analysis: U.S. Geological Survey Open-File Report 81-1086, 148 p. (NNAA870518.0068) "" - Rogers, A: M., Harmsen, S. C., Cair, w. J., 3ad Spence, W., 1983, Southern Great Basin Survey aeismxlogical data-report for 1981 and preliminary data analysis: U.S. Geological Ope'-File Report 89-669, 148 p. (NNA.890523.0102)" Rogers. A. M., Harmsen, S. C., Herrmann, R. B., and Meremnonte, M. E.,1987aA study of ground motion attenuation in the southern Great Basin, Nevada-California, using several Reseav. 92, , techniques for estimatýs of Q., log Ao, and coda Q; Jouýnal of Geophysical p. 3527-3540. (NNA.890713.0184) -- " Rogers, A. M., Harmsen, S. C.,'and Meremonte, M. E., 1987V, Eialuation of the-ieismicity of the southern Great Basin and its relatibnshili to the tectonic'framework of the region: U. S. .. 'Geological Surve Open-File Report 87408, 196 p. (HQS.870517.1409):. Schuenemeyer, J. H., Koch, G.S.,'and Ln, R. F.21972, A cdn puter program to analyze directional data, based on the methods of Fisher and Watson: Jgrnal of Mathematical Geolog, i, 4, p. 177-202. (NNA.920211.0045)" , Schweig, E. S. MII, 1989, Basin-range tectonics in the Darwin Plateau, southwestern Great Basin, - California: Geological Society of America Bulletin, v., 101, p. 652-662. (NNA.920529.0055) Snoke, 1. A., NMunsey, J."W., Teague, A. C., and Bollinger, C. A., 1984, A program for focal mechanism determination by combined use of polarity 'and SV-P ýmplitude'ratio data: Earthquake'Notes,v. 55, p. 15. (NNA.920211.0046) Stewart, J. H., 1988, Tectbnics of theWalkir Lane Belt, Western' Great Basin: Mesozoic and Cenozoic Deformation• in'i Zone of Shear, in Emit, W. C.-, ed., Metn6orphisrzi and crustal United States, Rubey Volume VII, Prentice Hall, Englewood Cliffsx, !• ~~~~NewNN0evolution Jersey, of p'.the 683-713.-western (NNA.900)614.0535) • '.. = •.. . 'I', Stewart, J. H., and Carifn, J."E.J1978,' Ge'ologic Map of Nevadia. U.S. Geological Survey and •ll .Nevada Bureau of Mines and Geology, map, MF-930, Scale 1:500,000. (HQS.880517.1505) Swadley-, W. C.i Yo~unt, J. C., and Harding, S. T., 1988, Reinterpretation of the Beatty scarp, Nye County, Nevada, in Geologic and Hydrologic Investigations of a Potential Nuclear 30 I Waste Disposal Site at Yucca Mountain, Southern Nevada, Carr and Yount, eds., USGS Bulletin 1790, pp. 113-120. (HQS.880517.1505) NOTE: Parenthesized numbers following each cited refe~hnce are f6r U.S. Department of Energy "OCRWM Records Management purposes onlynd should not be used when'ordering the publiction. Appendlx A SGB earthquake locations for 1991 . and quadrangle map names to which loctions are keyed The local hypocenter summary column headings are for the mot part self-explanatory. IUTC is Universal Coordiziated Time. Horizontal error equals' 1dx /d --edy2, where and idirefer to 'the HYPO71 standard errors in longitude and latitude,-respectively. Vertical error is the HYPO71 standar'd error in depth ,(dz).' AZI GAP" ,is the azimuthal gap, that is, the largest angle subtended by the epicenter and any two'circularly adjacent s.ations with positive phase weight. "QI" and "Q2' represen, two HYPO7i byplocenter quality estimates as defined by Lee and Lahr (1975). "DS5 is a code for data source: A for analog seismograms, (data scaled from Develocorder fi!xn, starting depth, z0 ,'at 7 kinfor iterations), I for -data scaled from digital 'selsmogramrn. The code "Y, means the Yucca Mountain velocity model [Appendix F, Figure FY(b)] was used to determine !the hypocenter (either analog or digital data miy have been scaled for those-earthquakes). Vario-us values are tried for z0 , the initial hypocenter guess.'zo and yo are always taken to be near the earli-st-reporting station. When equal final RMS values occur for solutions having different zo, the solution deiived from the z0 7.0 km siarting value is I "reported (although the choice is arbitrary) Mca is the coda-average magntitde, Md is the duration rniguitude estimate' MLh is local magnitude from horizontal-component ins truments, MLv is local magnitude from vertical "component instruments, MLc is the maximum of station magnitudes from oyerdriven (clipped) Srecords." Anmplitudes recvered froiver~tical-component data are multiplied by 1.75 to provide an approximate horizontal-equivyalent amplitu'de. 'The depths may~be followd by one or two stars. One rtar means that the depth-of-focus standard'error esatimate was very large (>_ half -'crustal thickness). Two stars imply that the depth was fixed by HYPO71 during the last several 'iterations for hypocentei, because the data laicked resolving power for that parameter. DELMIN is the minimum source to stition distance in'kin, ind RMS RES. is the root-mean-square traveltime residual in sec.'#N PH. is the iiumber of (P+S) phases having positive weight in the SsmlutioL.'Finally, U.S.G.S. quadrangle is the name of 71-minute or 15.minute topographic quad rangle in which the epicenter lies. The topographic quadrangle names appearing in this report are extensively revised from those appearing in previous open-file reports of SGB seismicity. Appendix A excludes all "low-frequency* seismicity associated with NTS nuclear device tests. Such phenomena include aftershocks at ultra-shallow hypocentral depths and cavity -, collapses. Such 'events,; though having a tectonic significance, are strongly associated in time and apace with testing, and their inclusion in the Appendix A seismicity catalog would probably bias any effort to determine natural seismicity rates in the northern NTS from this catalog. See Appendix C of this report for further details on these "low-frequency' events. 31 ) j. *'-' C ..4** * ( 116.00 115.5" 1 15* % 4~4% 38. 74ýV ýk380 .4 % Ab - d 4 evf------'75 UP -~ ~ 4 II q94T0, _ I_ I I .. I a 1 14.50 NTS - SEISMOGRAPH STATION p Figure Al.- USGS topographic quadrangle names in the northeast quarter of the southern Great Ii Basin. SI '4' I., I 32 C 116250 : 116 115.59 -115* 114.5* - .- % - 370 4ke -.- - 36.50 + ý.4 .50 ., - - - -.. 35 . . .• 114.50 < 1 16.25ow CALIFORNIA~...... - : . . . NEVADA S...... •SEISMOGRAPH ,•' '- - STATION >-: the southern Great ,:Figure A2.- ,USGS topographic quadrangle names in the southeast quarter of Basin. 33 U vPM I f i I IS Ii C I. f 1' 1180 CALIFORNIA NEVADA 116.25' SEISMOGAPH STATION Figure A3.- USGS topographic quadrangle names in the northwest quarter of the southern Great Basin. Iol I | ! 34 7- -- - *1 *V70 '410i CiIIFnRNIA I 117 NEVADA - 116.5 - -~ - %A 0 5 k%*r0*I4-- 0 t dz4 NTS A v~r .5 4 If., F. ) Nj p L sIA I- ~.5* 4 I 4r I 'I 4 I41tIf h;-ý,t": k 4 3 4% 4CSV '4, N. 4 4I. g *0 ______£ .1.______L .4 1180 1 16.250 SEISMOGRAPH ~STATION the southwest quarter of the southernGra - igure A4.-"USGS topo~grap hic .juadranglc naries'in Basin. 35 1991 LOCAL HYPOCENTER SUIMARY - SGB EARTHQUAKES STAND STAND AZ! 000 DEL- R IN DATE - TIME LATITUDE LONGITUDE ERROR DEPTH ERROR CAP 12S MAGNITUDE ESTIMATES uWN RES. PH. U.S.G.S. (UTC) (DEC. N) (ODG. W) (KW) Z(O.) (DEG) Uca Ud MLh MLv WL¢ (1Ki) (SEC) QULADRANGLE JAN 2 15: 4:27 36.756 118.24e 1.3 5.55 1.3 186 801 1.01 0.59 1.0 3.2 6.18 11 SKULL UTN 3 4: 0:30 37.043 115.547 6.4 3.41o - 170 GCl 1; 55 1.86 1.67 39.9 0.12-13 SOUTHEASTERN MINE 3 21:47:18 36.525 117.364 2.0 0.79 1.5 231 801 1.68 1.58 1.32 15.4 6.23 11 COTTCONOO(O CANYON 4 9:47:38 37.013 116,234 0.5 5.49 0.7 78 M)I 1.83 ' 2.0 2.7 6.12 15 TIPPIPAN SPRING 5 2:16:23 36.734 116.433 0.4 S9.22 0.8 155 Act 0.72 6.6 008 13 LATHROP WELLS 5 2:24: 6 36.734 116.414 1.3 8.92 0.8 306 DOI 0.88 0.06 5.8 0.10 9 LATHROP WELLS 5 2:48:27 36.734 116.433 0.6 9.21 1.0 111 ABI 1.34. 0.588 6.1 LATHROP 1.351.597 0.14 18 WELLS 5 2:48:35 36.742 116.420 9.25 0.9 162 ACi 0.92 1.3 5.0 0.15 153LATHROP WELLS 36.743 116.420 1.8 7.28 1.5 218 801 6.87 5 3:16: 8 8.8 0.36 4.9 0.15 10 LATHROP WELLS 5 4:20: 0 36.739 116.421 8.60 0.9 223 0.68 0.22 5.4 0.10 11 LATiHRP WELLS 5 5:58:17 36,738 116.430 8.95 0.7 228 •1.05 0.56 LATHROP _1.1 1.67 5.7 0.08 12 WELLS 5 6:55:22 36.729 116.433 7.57 0.6 67 80l 1.63 1.42 1.3. 6.7 0.12 37 LATHRO WELLS 7 4:16: 5 36.748 118.434 8.16 1.0 201, 6.99 6.54 5.6 0.15 14 LATHROP WELLS 7 4:54:49 36.861 117.295 0.9 11.24 1.7 .85 2.09, 2.3 11.7 0.21 13 DRY BONE CANYON 7 13:4e:38 36.699 116.315 0.6 2.32 1.3 162 Bel 0.41 1.0 6.1 0.87 9 STRIPED HILLS 1.90 7 17:31:52 .36.751 117.739 2.3 16.95 6.9 263 COlMCI 1.45 1.44 34.4 0.23 '9 WEST Of TEAKETTLE JUNCTION 8 7:15: 1 36.986 116.334 0.5 7.31 1.1 1"0 'ACIOc1 0.93 0,29 7.2 0.11 13 TOPMAH SPRING 8 21:33:44 37.220 116.581 1.1 2.67 2.9 157 Dc! 1.23 0.88 9.5 0.04 13 THIRSTY CANYON 9 26:33:23 38.826 116.188 1.5 14.95 2.4 161 Asi 1.38 0.64 6.3 0.16 16 CANE SPRING 11 9:47:35 37.381 117.332 3.4 1.12 7.4 209 0.75 0.72 11.1 DCIACo 0.13 6 MOUNT JACKSON I1 14:27:48 37.189 117.434 0.5 7.88 2.1 124 60.89 0.88 0.83 19.7 0.13 12 WEST OF COLD UTN 12 8:48:44 36.978 116.425 0.3 1.66 1.6 172 ACI 1.25 0.75 0.8 7.4 0.08 13 PINNACLES RIDGE 4.:, 12 14:51:49 36.977 116.426 0.3 0.64 0.4 92 ABI t.04 0.58 0.8 7.4 0.07 14 PIN4ACLES RIDGE 12 16:42:34 37.844 115.0862,' 4.0 2.58 7.6 141 1.51 1.27 0.8 4.3 0.16 8 WHITE RIVER NARROWS 12 18:25:13 37.016 116.288 0.5 5.00 0.9 126 ABIACI 2.25 1.52 1.56 1.9 5.7 0.13 17 BUCKBOARD MESA 12 18:26:15 37.019 116.292 0.6 1.44 3.1 1 9 1.48 1.15 1.1 6.0 0.17 !5 BUCKBOARD MESA 12 18:31:37 37.022 116.293 8.2 4.53 0.4 153 0.94 VC'ACI 0.54 -68.4 0.62 8 BUCKBOARD LME 12 19:58:42 37.022 116.293 6.4 4.56 0.7 131 DCI 1.05 0.82 0.9 5.9 0.08 16 BUCKBOARD MESA 12 20:48:39 37.030 116.298 6.5 7.86, 0.8 139 1.88 1.66 1.6 6.2 0.11 16 BUCKBOARD MESA 12 22:40:23 37.019 116.292 0.4 3.74 1.0 129 ABI 0.90 0.47 1.9 l.-.11BUCKBOARD ME 12 23:39: 3 37.469 114.726 2.3 1.44 4.7 235 ABI 1.57 1.23 '21.7 15.3 0.16 I1"SLIDY MTN 13 3: 6: 1 36.639 116.387 0.3 6.53 0.5 135 ABI 2.03 1.63 1.4 4.3 6.07 18 LATHROP WELLS 13 5:34: 1 35.647 116.375 1.5 7.63 1.4 233 6.97 0.66 3.1 0.17 9 LATHRO WELLS 13 13:10:53 37.013 116.297 0.4 0.C8 0.6 139 ACI 1.06 0.52 6.6 0.14 16 BUCKBOARDOMESA 15 3:12:48 36,888 116.269 0.7 10.79 0.6 261 AD! 0..9 0.47 5.0 0.06 13 TOPOPAH SPRING 91• 15 19:48:48 36,351 116.866 6.5 7.63 2.6 162 BC! 1.16 1.37 1.21 21.6 0.13 14 DEVILS GOLF COURSE 16 3:35:55 37.131 117.e92 6.7 2.60 4.4 125 1.32 6.94 1.12 17.3 0.16 9 DONNIE CLAIRE 16 9: 9:22 37.489 117.93e 1.2 4.37 2.3 226 .CI 1.51 1.85 2.0 7.4 0.18 13 CHOCOLATE MOUNTAIN 16 14:51:55 37.622 116.293 6.5 3.90 1.2 131 AB! 1.27 I.64 0.8 5.9 0.11 14 B UCKBOARD MESA 19 3:10:31 37.022 116.302 1.2 2.14 2.4 154 BC I 6.S3 0.49 6.7 0.13 12 BUCKBOARD MESA 19 3:31:55 37.015 116.299 0.4 1.50 2.3 143 OcI 0.90 0.41 6.7 0.13 13 BUCKBOARD MESA 19 7:34:45 37.111 114.573 3.1 7.04* - 292 CDI 1.62 0.44 1.50 1.70 1.9 53.6 0.12 7 VIGO 19 8:49:48 37.190 117.406 0.3 8.67 1.2 117 AC! 1.06 0.85 0.81 18.0 0.08 11 WEST OF GOLD ITN 19 13:17: 9 37.262 116.989 0.3 9.90 1.1 64 AC! 1.63 1.97 1.60 1.6 24.1 0.11 27 TOLICHA PEAK SW - I L 1991 LOCALHYPOCENTER SUMARY - SGO EARTHOUAKES " STAND STAND AZI OC ";EL- RI IN ES. UIN RES. PH. U.S.G.S. DATE - TIuE LATITUDE LONGITUDE ERROR DEPTH ERROR GAP o12S UAGN ITUOE EST I MAT '(UTC),, (DEG. N) (DEG. W) (KU) Z (KM) (DEG) Uco Ud ,Lh ULv ULc (KM) (SEC) OJADRANGLE JAN 19 15:58: 6 36.764 '117.714 2.1 10.31 5.7 240 CDI .1:59 1.38' 1.62 28.6 0.27.15 WEST OF TEAKETTLE JUNCTION 20 18:25:25 37.262 1116.988 8.2 9.61 1.0 64 ACI 1:46 ' 1.08 1.44 1.6 24.3 6.69 22 TOLICHA PEAK SW '117.522 1.3 4.68 4.6 150 BCr 1.16 1.22 ,19.6 8.22 9 TULE CANYON 21 3:27:41 37.347 8.18 22 9: 4:22 36.628 ,117.126 6.7 2.7 102 581 1.52 1.79 1.66 1.6 14.3 6.18 13 STOVEPIPE WELLS NE 23 15:46:39 37.639 116.218 1.7 5.72 1.3 259 S0I 0.94 0.68 • 1.6 0.19 9 TIPPIPAN SPRING 24 13:55:43 36.955 117.226 6.5 11.26 1.3 79 ABI , 0.89 11.8 0.1311 GRAPEVINE PEAK 1 0.5 1'.7 25 7:21:22 37.317 117.615 5.26 "102 .BI 1.05 1.13 1.24 9.8 6.13 13 TULE CANYON 26 1:31:13 '36.126 116.156 8.51 231 ADA 1.53 6.2 O.H 4 STEWART VALLEY 26 2:31:31 37.293 116.618 3.8 6.95 6.9 196 CDA 1.36 2.6 0.17, 5 TRAIL RIDGE 27 16:47:27 36.792 116.283 1.6 8.77 1.7 114 BOA 0.76 5.5 0.19 12 GEORGES WATER 28 6:12:46 37.641 115.993 2.6 7.86 3.1 212 BOA 1.14 13.7 0.17, 9 PAIUTE RIDGE 28 12:43:31 37.e85 116.073 3.4 3.16. 217 COA 1.61 13.6 6.18 5$YUCCA FLAT 29 19:42:26 37.248 115.515 6.7 14.26 2.6 156 BCI 1.46 1.46 1.28 24.7 6.e9 8 FALLOUT HILLS NE' 30 3: 5: 6 37.385 115.455 6.6 3.31. 112 CCI 1.41 1.85 1.61 28.7 0.15 12 CRESCENT RESERVOIR' 30 4: 8:58 37.427 116.357 6.2 6.46 1.5 118 ACI 1.30 1.84 1.12 1.5 21.6 6.06 15 APACHE TEAR CANYON 38 18:8:16 36.907 117.460 0.7 8.87 1.0 179 ACI 1.37 1.25 12.3 6.16 16 TIN MOUNTAIN 38 21: 4:14 36.727 116. 172 1.3 0.32 6.9 237 0I1 0.30 9.1 0.16 7 SPECTER RANGE FER 4 15:25:37 36.559 116.677 2.6 7.81 5.6 205 B00 1.27 13.5 6.12 16 POINT Of ROCK .11 5 2: 2:26 37.449 115.533 1.3 7.6 141 CCI 1.23 0.95 1.10 20.1 0.24 16 GROOM RANGE NE' "'ft. 5 17: 4:19 36.634 116.388 6.4 6.77 6.5 186 ACI 1.28 1.63 4.5 6.08 15 LATROP WELLS 6 *48 6 16:33:36 37.381 117.104 6.4 6.5 83 ACI 1.34 1.43 "1.5 16.2 0.11 19 SCOTTIYSJUNCTION NE 7 17:38:25 36.412 116.323 6.4 6.48 1.3 109 ACI 1.06 1.17 1.01 13.8 6.16 14 DEVILS HOLE 9 26:51: 7 36.637 116.387 6.5 6.96 0.6 135 ABI 1.25 6.89 4.4 6.16 14 LATHROP WELLS 10 1:43:56 36.461 116.965 1.1 11.27, 2.1, 139 OCI 1.01 1.47 1.86 1.4 14.3 0.16 11 WEST OF FURNACE CREEK f 10 21: 1:59 36.65e 116.363 6.4 7.12 0.4 221 AD[ 1.36 6.43 2;1 0.05 11 STRIPED HILLS 11 13: 6:54 37.177 116.681 6.2 6.97 6.8 169 ABI 1.79 - .64 6.2 6.04 9 OAK SPRING 'I 13 22:56:15 36.690 116.3e7 8.9 1.60 2.2 171 BCI 1.11 6.45 5.8 0.12 13 STRIPED HILLS 15 8:46:43 37.379 117.105 6.5 0.93 6.8 138 ACI 1.20 1.46 1.19 16.1 6.16 12 SCOTTYS JULCTIOI NE 17 12:56:28 36.758 116.120 2.2 7.69 2.5 259 OI 1.06 C.63 1.4 11.5 0.18 9 CANE SPRING 16 17 16:54:32 37.421 115.218 6.7 1.75 2.7 84 DCI 1.23 1.12 1.65 1.4 14.0 6.16 ASH SPRINGS 9. 0.684 6.5 83 ACI 1.66 1.67 1.6 16.7 6.12 15 SCOTTYS JUNCTION NE 17 23: 3:59 37:38e 117.097 0.4 1.89 18 3: 8:46 37.419 115.215 0.5 1.32 1.7 123 ACI 2.23 2.6 14.6 6.14 13 ASH SPRINGS 18 16:18:41 37:438 115.265 6.6 2.25 1.7' 109 DCI 2.34 1.92 2.6 14.1 6.21 27 ASH SPRINGS 116.695 6.7 6.5 98' A81 1.79 0.46 1.73 1.9 2.9 6.16 12 ROLLER COASTER KNOB 18 22: 0:58 37.651 0.*50, 19 11:33:17 36.655 115.697 6.7 1.5e 1.7 212 501 1.27 6.96 11.6 0.18 13 INDIAN SPRINGS NW 19 15:29:11 37.720 115.986 6.6 1.32' I'6 125, ABI,1.03 1.25 1.4 5.2 6.12,11,lrITE BLOTCH SPRINGS NM 26 19:46:57 37.425 115.212 e.7 2.05 2: 4' 78i 66I 1.3'9, 1.45 1.32 1.8 14.4 0.17 1t4ASH SPRINGS 21 5:49:52 37.186 116.953 0.4 10.30 1'.7 86 ACI 1.52, 1.80a 1.25 26.7 6.14 18,SPRINGOALE IM 21 16:46:46 37.118 115.249 e.9 1.28 2.1 183' 801,1.48' 1.48 1.29 1.7, 7.9 0.16 15 LOWER PAHRANAGAT LAKE SW 23 1:14:47 37.3911 115.244 6.4 0.73 8.8 93' ACI'1.22 1.17 0.95 1.4 17.168.13 10 ASH SPRINGS 186 0.4 1.91 2.2 113, 881 0.87 0.45 1.1 .7.7 0.14,13 SKULL UTH' 24 2:47:43 36.750 116. 6.4-• 36 116.417' 10. 0.6 145 AC1 1.07 6.81 7.2 6.16 16 LATHROP WELLS 24 5: 6:26 36.664 1 "1 1•. '.' I -I 6.75 0.4 11.18 6:8 126 ABI 6.88 1.2 6.5 e.1 15 SPECTER RANGE NW 24 9: 3:46 36.724 116.2e2 +..e.61 * .4 24 13:28:19 36.628 116.317 3.2 2.56 1.6 295,_ CDI , 2.8 0.29 9 STRIPED HILLS 'I' a. 4 5.. 1991 LOCAL WYPOCENTER SU61WARY - S08 EARTHOUAXES STAND DATE - TIME LATITUDE LONGITUDE STAND AZI 000 (UTC) ERROR DEPTH DEL- Ri.S IN *1 (DEG. H) (DEG. W) ERROR CAP 12S MAGNITUDE ESTIMATES H(KU) (KW) Z(KU) (DEG) WIN RES. PH1. U.S.G.S. Uca Md MJLh MLv ULc (KN) FEB 25 9:48: (SEC) QUADRANGLE 42 37.296 114.257 I.e 25 15:12: 36.731 8.66 244 'SO 15'.538 23 116.194 0.5 9.75 6.8 2.8 54.7 6.'21 46 *1p.REG1'a4AL.** 26 5:25: 52 37.348 116.551 67 82 AAI 1.84 2.69 1.74 1.4 15 29 '10264 2.6 p 7.1 0.16 22 SPECTER RANGE ?m 27 6: 11: to 36.267 116.856 0011.62 2.11 0.98 6.2 9.78 6.9 121 .1 .5 12.7,8.16,14 DEAD HORSE FLAT 28 19:41: 25 56.724 116.289 ABI 1.21 1.20 1.3a 19.6 0.67 28 20:41: 6.4 16.59 6.8 ~127 ABI 1.22 14 DEVILS GOLF COURSE 18 36.725 116.195 0.8 1.75 1.25 1.3 6. 86.15 21 SPECTER 9.58 0.6 127 ABI ,1.86 1.40 0.82 RANGE Na 1.2 ,7.2 0.14 ,13 SPECTER RANGE Na MAR 1 .4:32; 28 56.556 115.197 0.7 11.07 5 1 4:54: 24 36.729 116.202 6.8 141 oCI 1.86 1.76 6.5 11.59 0.6 123 1.8 6.5 6.21 19 SHEEP PEAK 1 15:52: 43 37.188 117.566 ABE 1.14 1.75 1.00 *665 0.09 1 16:55: 1.9 6.95 4.2 186 oci 1.16 15 SPECTER RANGE NW 42 356.728 116.201 1.07 6.87 15.7 0.21 10 GOLD 1 17:24:. 56.631 0.4 10.74 0.6 124 ABI 1.66 2.09 1.52 MOUNTAIN 56 115.644 1.5 66 6 .08 18 SPECTER $1, 1 17:50:,31 58.587 115.98 0.4 1.11 2.5 74 OCE 2.51 2.54 RANGE NW 14.71 6.8 162 2.2 16.4 6.23 36 INDIAN SPRINGS NW 8.4 ,ACE 1.6*1 1.62 2.1 8.4 0.12 20 NIAVI WASH, 2 15:58: 56.544 117.058 2 18:11::25 57.38a 9.*70 1.5 107 ABE 1.32 117.254 6.3 1.52 1.7 17.2 0.12 17 GROTTO' CANYON 3 1: 4:.38 37.584 6.16 6.4 126 ABE 1.52 1.06 117.252 1.3 2.*53 1.4 9.7 0.16 17 IMOUT,.JA~CKSON 3 17:53:~so 37.024 5.1 119 Bel 1.65 1.06 116.198 0.7 9.37 1.4 9.2 6.19 16 IOUNT JACKSON 4 1:43:~32 37.144 115.148 1.0 159 ACI 6.91 1.15 6.78 1.4 7.25 1.8 259 801 .3.1 6.15 12 TIPPIPAN SPRING 4 3:26: 18 57.018 116.199 1.60 1.72 1.57 4.4 0.5 8.61 6.6 89 MEI 1.22 1.56 1.21 1.6 0.101 15 LOWER PAIERAN.AGAT LAKE NW 4 13:13;I 5.5 0.11 19 TIPPIPAH SPRING 50 36.192 116.533 0.5 4 16: 4:., 36.714 0.*65 6.4 154 BCI 1.11 115.892 6.9 1.23 17.7 0.15 8 EAGLE 5 7: 6:4 58.458 116.226 4.15 2.6 139 DCI 1.65 MOUNITAIN.. 6.6 1.86 2.1 1.5 7.6 0.20 17 MERURMY 6 6:15: 56.616 116.272 172 OCI 6.93 6.51 7 0:46:6 6.5 3.77 1.6 156 ANE 1.53 5.1 6.12 1S SKULL WTN 37.261 114.650 2.6 6.70 1.5 6.9 0.11 13 SKELETON 9 21:55:3 57.396 7.00 16.3 244 COI 1.48 HILLS 116.610 0.5 10.26 1.58 1 26 1.6 27.1 6.21 10 GREGERSON BASIN 6.7 147 ACN 1.65 5.-. 7 1.34 11.9 0.05 If COLD FLAT WEST 9 22:17:2 37.112 115.237 16, 21:58:4 1.1 2525 2.0 189 901 1.76 37.113 115.219 1.89 1 -17 1.2 7.7 0.22 16 LOWER 10 21:49:5 37.129 6.3 5.46 6.9 125 981 3.25 PAJRANAGAT LAKE SW 115.233 1.2 4.55' 4.67 ' 5.5 6.9 0.22 37 LOWER PAIRANACAT 16 21:50:2 2 37.117 115.248 1.5 Sa4 90 1 1.73 LAKE SW 6.6 6.58 3.7 11.77 1.47 1.7 6.6 6.19 15 L~wMEPAHRANAGAT LAKE NW 18 25:31:2 57.139 115.248 258 DOI 1.22 1.56 1.46 7.5 6.24 11 1:36:4 2.8 -a.19 1.1 257 1.1 9 LOWER PAHRANAGAT LAKE SW 37.122' 115.240 CS1 1.48 1.09 1.67 1.0 6.4,0.21 11 LOWER 1.5 1.:98' 2.2 185 901 1.67 PAHRAN.AGAT LAKE No 1.73 1.54 '.7 6.9 0.26 15. LOWER PAHRA14AGAT 11 2:56: 37.117 LAKE SW 7 115.238 6.8 2.25 11. 5: 7:4 57.120' 115.239 1.5 189 ADI 1.59 1.47 1.51 1.6 1.65 2.1 1.7 7.5 0.14 15 L.OWE'R PAHRAJ4ACAT LAKE SW 11 4:55:5. 37.141 115.239 187 901 2.52 2.04 2.4 7.1 11 6.5 2.688 6.6 143 0.19-17 LOWER PANRANACAT LAKE SW 9:51:5 57.282 115.251 ACI 2.43,8.62 2.80 2.69 2.5 5.6 6.14 27 11 15:19:Si 6.5 1.31 1.5 112 9CI 2.51 0.54 LOWER PAHRANAGAT LAKE NW 57.271 115.240 1.1 2.81 2.53 2.9 15.2 0.25 35 11 15:55:5: 37.118 5.26 5.8 121 CCI 1.35 ALAMO 115.253 6.7 1.36 1.40 1.6 12.2.0.16 16 ALAMO 2.23 1.8 159 1.77 1.58 12 1.7 7.0 6.16 14 LOWER PAHRANAGAT LAKE 6:24: 7 37. 274 115.241 SW 12 7 1.2 6.21 5.6 5:18:4; 37.132 115. 244 109 CCI 1.45 1.40 1.13 1.5 12 4:26:2;7 1.5 1.41 2.1 225 12.6 0.16 16 ALAMOa 57. 118 115.235 WE, 1.41 I1.22 1.15 1.2 6.5 12 5:'5; 1 1.4 4.55 1.8 23a 0.12 It LOWER PAHRANAGAT LAKE NW 37.121 115.237 901' C.41 1.27 1.65 1.5 7.1 0.16 13 12 12: 1:51 1.7 4.87 1.8 237 901 'LOWER PAHRANAGAT LAKE SW, 37. 261 115.245 1.59 I1.43 1.51 1.5 6.8 0.16 10 LOWER 12 12;51:50 1.4 4.24 9.1 126 OCI 1.28 PAI'RANAGAT LAKE SW 37.272 115.241 1.51 1.17 13.5 0.18 12 2.01 ý5.2 1,21 CCE 1.29_, ALAMO 12 15: 54: 21 36.939 116.595 5.54 12 23; 14: 1a 37. 284 2.9 145 OCY 1.25 677 6.8 115.232 6.6 1.44, 11.1 0.67'15'EAST Of BEATTY MTH 2.1 -112 OCI 2.16 20.,132.1 15.4 6.15 14 ALAMO '*1 5.. ; I . '' ; r *, 4*'44 1 " '4 .- 4- 1991' LOCAL HYPOCENTER SIMAARJY* '- SCO EARTHIQAkES DEC-IWRS - siNo STAND I IN ' " '0' LONGITUDE ERROR DEPTH ERROR CAP ,12S'UACNITUOE ESTI•ATES, UNIH RCS. PH. U.S.C.S.: DATE - WiUE. LATITUDE - Io M< (UTC). (DEC. N) (DEC. W) H(KmJ) (KU) Z(KM) (DEG) ,ULh ULv ULc (XU) (SEC) UUAORANLE ACI, 1.210 ":0.58 6.9 106.3 6.15U9'HIKO NHE' 12 'Ii. 45 e.5 "8.48 6:8 114 MAR 23:18:31 3i7.687 •115:.23A 6;67 '2.4 128 'B81.1.13 6.94 '1.17 ,12.1 6.67 7 ALAMO I . ",2 37.270 8.6 12 23:36:'4 115.231 1.9 234 101 1.64 6.86 1.56 1.55 1.7 6.5 0.18 11 LOWER PAIRANAGAT LAXE MY )13 3:18:49 37.126 1.6 4.43 115.237 6.8 2 . 77 ,2114 118 BCI 1.34 1.21 1.44 '1.8 12.6 0.11112 ALAMO'"" 13 6: 6:47 37.275 3.11. CC1'`1.59 1:59 -1.7S '1.8 '11.2 6.65 10 ALAM I I .37.261 ,115.238 0.7 123 13 22:39:15 16.82 'e 7 ,BCI 2.56;2.19 3.13 -2.51 3.1 4.9-0.1634 HANGING ROCK CANYON "14 •15:54:59 37.221 '117.699 e6.4 169 1.1 3.22. ý20e (bi 1.93 1.59 2 31.6 6.17;' 9 BLUE DIAMONI 14 ;19:22:,1 36.065 115.431 44 * DCiU1.61 1.76 A.49 1.9 20.8 0.13 24 SPRINGOALE NW 37.185 116;955 6.3 7.69 2.2 131 14 "21: 2:47 6.8 136 DCI 1.62 1.73 1.6 10.4 0.25 16 FRENCHMAN FLAT 14 21:55:52 36.754 115. 973 5.39 3.5 115. 973 '0.4 4e.48 6.6 134 ASI 1.47' 2.82 1.41 1.8 16.6 0.11 16"FRRCHW FLAT, 14 '22:52:40 '36.756 D9CI11.52 1.36 1.8 12.3 0.1017 BOMIE CLAIRE SW 15 3:23:37 .37.057 117.137 6.5 '4.19 2.4 87 '0.57 '5.1 0.12 14 SPECTER RANGE W 16 '7:36:33 364712 116.238 7.66 0.8 214 AD!,0.89' e.3 1:.8 182 '901 1.56 6.83 1.69 1.2 5.7 6.22"9 LOWER PAHRAXACAT LAKE NW i1;58:21 .37.132 115.232 8.08 1.8 16 6.7 DCI 1.49 ,1.33 1.86 1.5 13.6 6.22 12 BADGER SPRING 17 1:19:15 '37.274 115.251 6.4 0.31 124 115.243 0.6 7.78 1.9 126 ABI 1.28 1.32 1.15 1.5 11.5 9.16 12 ALAMO 117 12:53:45 37.262 Be 1.69 1.79 1.66 1.8 6.5 0.16 19'LOWERPA&UWNAGAT LAKE NW 17 ý17:-4:32 37.126 115.238 0.5 5.22 1.3 131 117.266 8.5 5.01 6.3 121 CCI.1.26 1.67 1.38 22.9 9.11: 9 RALSTON 17 -23:57:52 -37.556 6.6 206 AD!, 1.19 -e.66 1.24 2.669.11 16 MERCURY 18 )%7:19:21 36.637 115.967 6.6 10.57 "-1.56 1.74 1.7 7.7'817 1MTE lTTOPMOUNTAIN 18 16:22: 2 36.864 117.450 0.6 2.90 1.1 188 001 1.59 115.246 6.7 1.77 1.4 170 ACI' 1.49 I.e5 1.15 -1.1 2 '6.1 0.09 16 LOWER PARANAGAT LAKE NW 18 23:30:34 37.141 I.1. 2.0S 1.83 2.1 5.5 6.19 15 LOWER PPARANACT LAKE NW ,37.125 115.235 6.83 1.4 186 801,1.86 18 23:41:24 1.4 183 801 1.48 1.40 1.36 1.0 ' 6.369.18 17LOWER PAHRANAGAT LAXE NW S19 40:38:31 '37.128 115.236 6.8 "4.55 115.967 6.8 10.71 6.9 206 AD I• 1.88 0.90 2.7 0.14 15'MERCURY , " 19 6:55:20 -36.637 S4:71 1.5 1.79 '1.51 1.7 7.7 0;13 13!LOWER PAIHRAAGAT LAKE SW 19 ;5:15:,4 '37.114 S115.241 188 ADI 1.76 6e:7 _2."0.91'168 MERCURY' 36.i643 115.963 ,'.8 142 AC6'1.12 "P.75 19 19:24:48 6.86.6 1.44 1.6 18:8 6.15 14 EAST OF WAUCOBA SPRING 15:45:41 37.124 117.816 5.45 3.9 211 901 1.45 1.25 26 156 AC! 1.40 0.88 1.13 1.5 13.6 0.12 26 SPECTER RANGE SW 21 17:23:22 .36.546 116.166 0.4 7.62 1.4 116.592 •6.8 6.48 '3.1 143 DCI 1.66 1.32 1.5 119 0.19 13 THIRSTY CANYON 21 :19: 6:,2 37.159 6.9 1.43 23.8'6.17 12 LAST CHANCE RANGE SW 117.629 4.47 16.3 191 COI 1.24 "-1.56 £• 22 11:30:36 '37.619 1.34 1.32 1.8 12.6 0.15' 8 ALAM 22 15:27:35 37.271 115.229 1'.4 2.35 5.4 115 CCI 1.47 1'.1 4.4 6.15 12 MINE UT, 6-36.894 116.164 1.1 5.57 241 W 1 1.63 0.66 22 ,,16:52: 90D 1.35 1.1 7.1,6.16 16 LOWER PAMRAXAGAT LAKE SW 37.116 115.232 1.5 4.26 1.8 '243 1.37 1.33 22 19:11:36 1.5 0.85 19.3 6.16 12 LEELAND 22 21: 0:16 .36.622 116.559 0.7 10.68 193 ADI 1.20 116.953 e.4 4.57 4.7 112 OCI l'53 1.62 1.48 1.8 17.9'0913'14 SPRINGOALE NW 23 1:52:25 f 37.129 i8'ALAtO 23 7: 2:13-37.272 115.232 0.9 8.35 2.4 117 981 1.34 1.16 6.96 '1.5 112.1'0.11 "5.2 19 CCI 1.31 1.31 1.13 A1.5 13.0 0.19 10 ALAMO, 25 , 8:33:46, 37.278 115.240 1.3 1.83 001 6.80 8.3 0612ý 17 LOnM PAIA•,A•T LAKE SW .4-. 25 15:18:53 '37.116 115.245 1.7 1.8 266 0.45 0.66 " e.5 BCI 1.29 1.07 1.33 17.2 6.1615 SPRINGOALE SW 26 2:33:49 37.123 116.955 5.11 4.1 116 6.5 9.19 1.4 153 ACI 1.64 1.63 1.4 19.9 0.12 13 TULE SPRINGS PARK 26, 5:59:26. 36.291 115.369 SE 115.762 1.7 :3.25. 263 CO! 1.31 658a 1.18 A1.4 14.4:'6.18 10 FRENCH"4 LAKE 26 14:11: 5,36.818 12 WEST Of" COLD MTN 26 16:44:36 37.156 117.389 6.5 11.5e 1.5 108 'ABl 1.69 S1.24 1.67 19.8'0.11 30 13:54:25 37.647 117.129 6.5 2.45 3.4 163 9CI 1.22 1.34 1.39 1 23.4 0.13 14 GOLDFIELD 115.241 1.7 1.56 2.3 236- "DOI 1.50 1.27 1.26 1.4 7.3 0.11 9 LOWER PAJRANAGAT LAKE SW APR 1 20:13: 1 37.120 1.07 1.6 4.6 8.15 17 SPECTER RANGE MW 3 19:22:10 36.718 116.231 3.68 e.8 126 881 1.33 2.61 ' I .3 . ' . 1991 LOCAL HYPOCENTER SMk,,RY - S08 EARTHOAES STAND STAND AZI 000 DEL- RMS IN I LONGITUDE ERROR DEPTH ERROR GAP' 125 MAGNITUOr ESTIMATES MIN RES. PH. U.S.G.S. DATE - TIME LATITUOE H(KM) MUL JLc (KM) (SEC) JADIANG LE (UTC) :. (DEG. N)' (DEG. W) (K1) Z(aM) (DEG), ,ca Md ULh P 116.257 0.3 3.49 8.6 223 ADI 1.35 2.06 1.1 4 1.4 7.4 6.86.15 STRIPED HILLS. AP'R 4' 1:19:11 36.677 SAND SPRING 4 8:53:41 37.232 117.565 8.7 9.61 1.2 127 AsiD 1.88 1.17 1.6 17 7.2 0.15'12 116.096 0.7 12.29 1.2 138 ADI 1.28 0.557 6.8 6.13 12 CANE SPRING S 2:33:50 36.536 12 KNOB 5 5;46:'3 37.650 116.694 0.7 8.55 0..5 96 B81 1.56. 1.5 1.0 3.0 6.15 14 ROLLER COASTER 5 14:44:16- 36.937 117.461 8.7 5.08 3.2 4 172 BC! 1.84: 1.8 16 2.0 12.3 0.15.13 TIN MOUNTAIN 6.8 3.5-9.11'15 TIPPIPAH SPRING 5 14:45:46 ' 37.021 116.195 8.5 4.98 8.7- 189 ADI 6.97, 14 5 18:26:48 36.753 116.231, 0~.5 8.11' 8.6' 16 AB! 1.35' 1.56 '1. 16 1.3 3.9 0.14 19 SKULL UTH 2.8 0.76 2.2 236 COI 1.73 1.91 1.5 1.8 7.1 0.23 It LOWER PAHRANAGAT LAKE SW 6 2:35:50 '37.1280 115.240 13 6 8:49:31 36.757 116.231 8.5 6.95 8.7 184 63! 1.21 1.71 1.3 1.2 4.1 6.15 18 SKULL MTN 6 12:34:29 36.752 116.231' 8.7 8.59 0.7 194', ADI 0.1 12 3.8.6.68-18 SKULL UTH 117.541' 6.7 4.635, 3.0- 91 BCI 1.13 1.03 1.1 a8 10.6 6.15.11 TULE CANYON 6 15:39:14' 37.277 1.8 4.1 6.13 11 SKULL UTH 6, 1834:.4 6 36.750 116.228 8.7 2.37 1.6 196 ADI 1.88 O.553 6 18:55:38' 37.811 116.727., 8.8 4.37 11.2ý 97 CC! 1.47 1.114 15.0 6.26I6,THIRSTY CANYON SW 8.5 8.92' 8.9 186 Bel1 11.86 0.7• 3.1 8.15,16 SKULL UTH 7 5:43:37 36.751 116.239 70 7 6:41:48 36.756 116.234 6.4 6.61 8.3 184 ABI 1.63 6.! 3.7 6.13 16 SKULL MTN ' I, 8 8:54:13, 37.022' 116.191 0.'7 4.55, 6.9 195 ADI 6.84 O.415 3.7-0.19: 9 TXPPIPAN SPRING 114.321 6.8..e 3.0 0 D U 3.40 46.60 *9o 86;*REGIONALo.. 9 4:53:22, 37.341 23 9 6:51:56 36.298, 117.174 6.3 1.41' 6.5 284 ADI 1.34-- 1.17' 1.2 13.2 6.04. 9 EIGRANT CANYON '.4 1.3• 82, EAST OF WAUCOBA CANYON 9 7:26:,3 36.974 117.778 7.00 7.7 226' CoI 1.86 1.61 1.112 2.0 34.7 6.22 12 117.572 6.5 6.56 1.2 84 ADI' 0.97 4.82 6.9 9.0 0.16 9 TULE CANYON 9 19:56: 6 37.288 $3 14 EAST OF WAUCOBA CANYON 16 12:12:52 36.966 117.764 1.1 3.39. -- 217 COI 1.73 1.043 1. 1.9 31.4 0.22 o..REGIONAL... 0 10 19:44:56, 37.143 118.808 2.1 7.68* - 246 Col 1.83 1."' 1.. 2.0 32.5 8.21;10 116.293 0.4 7.21 4.8 98 A! 1,.49 2.05 1.3;4 1.5 9.9 9.89'12 AMMONIA TANKS 11 13:17: 5 37.143 Ill CAMP DESERT ROCK' 12 7:56: 06 36.694 116.124 0.5 6.66 1.4 150 ACI 1.14 6.9 1.3 14.3'0."9 14 19 LIDA WASH SW 13 1:57:27 37.601 117.676' 0.3 0.07' 0.6' 188 ACI.I.89 1.47 1.82 I.1 2.6!' 16.9 6.1118 116.569 6.4 5.34 1.71 89 AC! 1.53 1.331 "12.3 6.16.18 EAST Of ECHO CANYON 13 15:56:44 36.479 14 EAST OF ECHO CANYON 13 16:.6:S8 36.488. 116.575 0.5 4.80 2.9 56 OCt 1.65 1.3 1.9 13.4 6.19 26 115.211 " 0.5 3.44 1.4" 125 881 2.78 2.58 3.39 2.7 78 3.0 6.6 0.10 47-LODER PAkHRANAGAT LAKE SW 15 6:53:37" 37:119' 11 15 9:44: 4 37.517 118.313 5.5 -1.162'.29 3.61.5' 186290 D9U-1.770 1.6 37.4 6.18 II.'***REGIONAL.. 15 16:.3: 35 37.116" 115.244" 6.7 ADI 1.14 1.23 7.7 6.16I 9 LOWER PANRANAGAT LAKE SW CANYON SE 15 18:16: 4 37.833' 116.598 6.3 8.41' I1. 133 AC! 1.16 6.6 45 16.9 0.87 16 THIRSTY 117.756' 1.4 9.33' 3.5 161 BCI 0 .99 1.4 1.6 13.4 6.28 12 HORSE THIEF. CANYON 15 18:54:53 37.315 32 15 36.807 117.883 2.9 2.14 6.4 291 COI 2.39 2.48 2.3 2.5 82.3 6.26 14 HAIWEE RESERVOIR 19:43:49 6.24 32 MERCURY. 16 22:24:28 36.649 115.958 8.6 11.95 1.6 59 BAI 2.24 1.53 2.13 2.2 2.6 1.3 1.2 3.874 1.7 263 601 2.11 2.22 2.1 2.3 66.5 6.16 17oesSouthern Groat Basin.* 17: 0:43:51' 38.258, 117.757 '5 17 2:22:59 38.253 117.726 1.6 5.81 2.1 261 601 2.43 2.5 2.6 60.1 0.20 16 **Southorn Groat Basin.. 14 36.488 116.572 8.4 2.41 1.5 88 ACI 1.42' 1.1 12.5 6.11 20 EAST OF' ECHO CANYON 17 13:22:31 '5 CANYON 19 7:42:52 37.282 117.574 6.5 8.78 0.9 82 A81D 1.42 1.60 6.9 1.4 8.5 O:11 11 TULE 117.379. 6.7 1:.05 2:3, 121 Bi! 1.20 0.5, 1.1 16 1.3 9.6 6.19 12 UOOBEHE CRATER 19. 8:14:0 37.881 15 19 12:45:38 37.294 117.752 8.7 8.59 1.6. 166 BCI 1.56 1.26 1.19 1.4 1.7 11.6 6.15 14 HORSE THIEF CANYON 116.141 6.4 8.08 6.7- 104 9811.69 ' I.556 1.6 7.8 6.19 36 TIPPIPAm SPRING 19 12:59:16 37.036 |0 19 14:35:26 36.610 117.355 1.7 3.50. -- 201' COD 1.84 1.90 1.6 44.3 0.27 18 miATUmNGO 118.443 2.0 "5.788 0 95 CDU 1.75 "' 2.0 48.5 0.13 8 o**REGIONAL999 19 14:37: 1 37.517 8.79 8.4 95 7 19 18:35:12 37.070 116.951 8.3 AC! 1.55 1.11 1.1 12.3 0.11 21 SPRINGOALE SW - ý I I I ý C') ------Mw IL-- - - 1991 LOCAL HYPOCENTER SUJARY - SOU EARTHNU W LS STAND STAND AZI TES DEL- l~SIN I- .RES. DATE -,TIME,• LATITUDE LONGITUDE ERROR DEPTH ERROR GAP 12S MAGNITUDE ESTIUA1 IuLv PN.- U.S.G.S. 'ULc (KM) (SEC), (UTC),. '(DEG. N) ,(OEG. W) H(XU)' (K1) Z(Ku) (DEG) Uc1o 1d . ULh QUADRANGLE ,117.919 APR 21 '15:,7:53 37"468 1.3a 1.7 •'214 801 2 .0 5 2.10 2.4 4.9 0.28,21 CHOCOLATE MOUNTAIN 21 19:57:1 ,36.572 116.137 .1.3 , 3.72. 86 Ccl 1.51 1.25 15.2 0.24 II'SPECTER RANGE SW 22_ 4:15: 5,,36.980 ;116. 136 6.3 7.57 - 6.6 166 AB I 1.13 0.51 -8.9 0.8, 15 MINE MTN ,, "22 5:42:29' 37.472 117.908 1.2 7.0e 1.8 191 801 1.46 1.26 1.45 5.2 6.16 9 CHOCOLATE MOUNTAIN "22.- 9:18:47., 37.554 118.473 2.6 .7.00. 317 COI 2.06 2.29 2.2.-52.606.16, 9*-9REGIONAL*** 5.6 23- 13:51:60ý:37.878 115.658 - 1.6 5.12 ,141 cci 6.88, 1.09, 1.5 '12.5 0.12 8'MCCLUTCHEN SPRING CCI- , 24 - 0:.7:49 36.071 :114.978 -4.0 -11 20 5.2 167 1.79, '26.0 0.411 8 HENDERSON' 24.', 8:46:582 36.840 116.236 ,0.3 . 2.41 0.6 122 A•I 1.03 6.61 0.55 6.2 0,10"16 SKULL MTN',`, 24, 21:13: 4., 37.349 +115. 817 0.7 0.24 6.6 66 BAI 1.40 1.35 115.813 1.1 4.3 0.24 16 GROO MINE' " 25 16:50:43 38.306 2.0 2.20 5.7 224 Col 1.*63 2.24 40.8 0.28 17 e*Southern Great Basine. 25 22:58: 7- 38.664 117.932 10.6 -1.54. 291 -DOI 2.18, ,.24 106.6 0.46'1e e*eREGIONALoo '26 '38.180 6.9 ,' 22:56:40 116.266 4.8 15.25 179 CccI 1.241 16.1 0.15, 6 esSouthern Great Basin.. - 27 , 3:51:46 37.116 1.33 115.241 11.8 0.14 2.8 188 901 1.65 1.47 1.1 7.5 0.16; 7 LOWER PNRAHACAT LAKE SW 27 14:56:37- 37.393 114.944 S1.5 - 1.14 3.9 183 ,BO0 2.96 1.19 1.42 0.92 9.5 0.14-' 7 DELAMARIN 28 - 9: 3:1C0 37.351 116.3a7 0.7 12.03 2.3 197 BOA 1.29 31.3 0.04" 7 DEAD HORSE FLAT 28 '21:57:36 37.334 117.529 6.6 -0.22 1.6 124 1.28 1.23 12.1 0.13 :Ae]ACI 9 TULE CANYON 29 8:31:11 36.717 S116.439 0.2 5.26 6.8 166 0.28 8.1 0.04 14'LATIROP WELLS 29 ,12:16:286 37.315 ,.117.514 -0.8 -6.71 "-2.6 ,87 I i -, 1.47, 1.37 14.6 0.19-12 +"2 + *• j )'•"'' TULE CANYON 18:13:435 36.479 114i.477 S29 fI9 -1.13 ,2.1 213 CODI 1.46,+ - 61.3 0.44 11 eoeREGIONAL... "'38 3: 4:31 3a.666 116.447 4.8 -1.54 4.6 293 COU 2.63 1.84' 2.01 47.3 0.25 12 *ooREGIONAL**. *36 11: 9:13" 36.705 116.277 0.6 8.22 1.1 126 0.44 1.1 ".4.1 0.19 17 STRIPED 38 HILLS 16: 3:48 38.447 117.888 5.3 -1.32 4.2 278 DO 1.98 2.24 2.27 77.2 0.26 15 ooSouthern Great Basino. 38 20:32:18. 38.389 117.898 6.2 -1.02 284 DO1 2.29 :5.9 DOI -.. 2.05 ' 75.3 0.28 11 eoSouthern Great Basino. 38,, 22:46:33 35.635 115.660 6.9 .2.69. 226 1.74 74.1,6.22 8 MESQUITE LAKE MAY 21 0.8 2: 0:54 -36.976 116.615 .6.4 ',2.50 173 'ACI 1.64 1.82 1.7 6.5 0.09 15 YUCCA LAKE ' 2 16:, 7:15 37.191 117.624 0.3 '5.47 -3.3 .87 ,DOCi 1.99 2.19 1.8 23.2,0.10 17 DCONNIE CLAIRE ,2 19:11:55 37.675 !..23+ 115.248 -2.2 :8.41 2.2 274 801-1.45 1.12 11.7 6.19 '9 LOWER PAHRANAGAT LAKE SW 3 3:19:46 37.238 117.585 0.5 8.31 1.5 113 B81 1.21 1.37 1.23 12.6 0.16 16 SAND SPRING ,+ 3 3:54:35 37.239 117.504 0.7 7.85 1.8 115 DO1 1.15 1.34 1.15 12.6 0.18 15 SAND SPRING,-. 3 26:18:29 ,36.916 .115.734 2.2 2.48 7.6 295 CDI 1.08 0.61 25.5 6.07 -6 QUARTZ PEAK NW 4 , 0:28:42 36.286 115.206 '1.4 7.06 86.8 125 CCI, 1.56 1.40 ,1.9 24.7,0.21;12 GASS PEAK SW .4 .,3:56:54 36.826 117.613 1.6 11.15 ,3.2 226 1301 1.35 1.68 ;1.52 ,18.7,0.25,14 TEAKETTLE: JUNCTION 4 5:1e:36 '36.808 S116.268 0.4 2.621 3.5 123 .881,9.78 '4 5:40: 3 37.160 0.38 '7.3 0.13A12 GEORGES WATER 116.681 0.2 7.31 6.3 125 ABI 1.46 1.6 1.3 4.2 6.07 25 THIRSTY CANYON MW 1.6 ,0:.1:44 36.728 116.272 ,1.4 2.67 0.5 108 ABI 1.42 2.26 1.62 ,1.5 1.6 0;13,17 STRIPED HILLS 6 5: 2:54 37.134 117.059 .6.6 9.39 2.3 131 B81-,1.14 0.80 0.79 17.0 0.16 13 DONNIE CLAIRE 7.'1 i 14:22:27 S37 115.225 00i '1.47 j+37 "2.5 2.i7 1.6 251 1.56 1.34 1.8 7.4 6.15 10 LOWER PAJ-RIkAGAT LAKE SW 7 18:39:14 7.137 S115.242 1.9 1.78 2.4 221 001 1.57 1.55 1.29 1.7 6.0 6.15-11 LOWER'PAHRANAGAT LAKE NW • •oo 8 7:44:34 "37316.819 116.264 0.2 1.55 1.1 126 ABI 0.77 6.08 6.8 6.10.16 GEORGES WATER 16 '3:40:48 F.271 117.626 6.3 6.41 8.5 96 ABI 1.42 1.55 1.58 1.3 4.8 0.09 160 6 2.1 17 TULE CANYON 12:44: 316.635 117."143 6.5 6.70: 104 o81 1.39 1.39 1.21 r,' 12.2 0;87 8 MESQUITE 16 13:17: 9 366.636 144 0.4 S1.47 FLAT 117. 6.93 1.4 104 ABI 1.39, 2.0 .12.0 6.09 15 MESQUITE FLAT 10 22:22: 8 365.636 117.141 0.4 6.10 11 9:46:19 37 1.6 163 Acl 1.30 1.56 1.32 12.3 6.08 14 MESQUITE FLAT 7.108 115.233 1.1 1.74 2.6 901 IP6 ,1.55 1.75 1.44 1.7 7.8 0.21 15 LOWER PAHRANAGAT LAKE SW I -. . -t .1 1991 LOCAL TYPOCO4TERSLI.,ARY - SOB EARTHQUAKES. , , STAND STANO AZ! 000 DEL- RMS IN DATE - TIME LATITUDE LONGITUDE ERROR DEPTH ERROVR GAP 12S MACGNITUDE ESTIMATES WIN RES. PH. U.S.G.S. (UTC)' '(DEC. N) (DEG. W) H(lKM) (KU) Z(KM) (DEG) WLh ULv ULc (K) (SEC). OQUADANGLE MAY 11 11:23:45 37.123 115.242 1.3 2.10 1.6. 233 0O1 1.47 1.43 1.22 1.7 7.0 0.14 12 LWER PAIHANACAT LAKE SW 11 11:27: 6 36.634 117.132 0.3. 0.57 0.5 102 AC! 1.64-, 1.72ý 1.9 13.1 0.12 17 MESQUITE FLAT, I1 -12:15:28, 37.124 115.234 2.0 1.96 1.9 237' W0! 1.43 1.38 1.45 1.0 6.5 0.13 9 LOWER PAHRANAGAT LAKE SW 12 0:24:31- 36.634 117:139 0.3 6.P3 1.4 104 AS! 1.17 1.44 1.10 12.5 0.08 14 MESQUITE FLAT 12 3:56:21 36.635 117.138 0.2 2.82 1.5, 102 AC! 2.46 2.05 2.2 12.6 0.11-17 MESQUITE FLAT 12 12:52:54 37.329 117.875 0.9 8.03 1.2' 201 AD! 1435, 1.20 1.44 1.7 11.1 0.13.13 SOLDIER PASS 0.4 15 0:35:42 36.915 16'1 83 9.16 0.8, 99 ABS 1: 29' 1.24, 1.6 3.5 0.11:18 MINE MTN 13 8:34:'3, 36.850 115.914' 6.4 9.10-: 1.3 1653 AC '1.21' 1.088 15.6 0.09.10 FRENCHIANFLAT 153 10:45:27 37.625 115.075' 0.7 0.61' 1.1 114 Bc! 11.61 1.57 1.14; 1.6 12.8 0.22411 HIKO HE 13 14: 9:45 36.851 I15.913, 0.4 8.59 1.4 166 AC! 1.10 0.78 15.6 0.09 16 FRCHIIIAN FLAT I3 19:46:30 36.635 117.128 0.4 0.39 0.6 I" ACi 1.37, 1.59 1.9 13.5 0.13 14 MESQUITE FLAT 14 4:30:56 37.395 186.181 0.2 4.37 1.1 133", 1.74, 1.533 .6 11.0 0.07 15 SUHDOW RESERVOIR 103 ACI 1.70 14 5:28-:46. 36.637 117. 129, e.4 1.45 1.5 3.• 1.76 2.0 13.4 0.11 15 MESQUITE FLAT 14 10:54:13 37.286 117.571 0.2 2.51 .5, 183 AS! 1.14. 1.08- 0.9 : 1.3 8.9 0.08 9 TULE CANYON 14 11:41:13 :56.633 117.137 0.5, 6.92 2.3 102 Be1 ,1.31 1.54 1.25 12.7 6.12 11 MESQUITE FLAT 14 11:44:50 38.636 117.139 e.7 7.49 2.9 891 1.52 1.65 1.37 1.4 12.5 0.14 12 MESQUITE FLAT 14 21:46:21 16.635 117.141 6.4 7.00 1.7 I03 A!I 1.26 1.60 1.54 1.4 12.4 0.09 12 MESQUITE FLAT, 15 4:17:47 36,633 117.138 e.6 5.10 3.9 104 1.78 1.8 12.6 0.14 14 MESQUITE FLAT 15 11:18:42 36.635 117.144 6.4 7.42 1.5 104 A•I 1.44 1.72 1.42 1.4 12.1 0.09 13 MESQUITE FLAT 15 12:12:55, 36.636 117.139 0.3 4.38 2.4, 102 BCI 1.38 £ 1.49 1.27 1.4 12.5 0.07 15 MESQUITE FLAT V- 15 20:'1:50' 36.630 117.150 0.5 7.12 1.3 1688 981,2.46 2.59 2.7 11.6 0.18 36 MESQUITE FLAT N 16 9:10:42 36.639 117.144 0.3 7.68 1.3 102 AB! 1.91 1.9 12.6 0.09 15 MESQUI7E FLAT 16 16:29:12 36.641, 117.139 0.5 6.99 2.4 i04 381 1.20 1.57 .1.19 12.4 0.13 12 MESQUITE FLAT 18 1:50:5 36.846 115.449 0.8 7.00 9.9 113 CC! 1.48 1.51 56.4 0.19 10 DOG ONE LAKE SOUTH 1.08' 0.65 18 6:33:27; 36.768 116.225 6.2 1.54 b.8 119 ABI 1.02 0.9 5.1 0.08 15 SKULL MTN 19 ,11:24:39 36.640 117.134 0.3 0.92 6.4 99l AC! 1.72 1.76 1.9 12.9 0.11' 16 MESQUITE FLAT 20 6.6 I11, 1.01 1. 6.5 SiMLIT "11:48:57 '37.599 114.968 1.43 2.1 9B1 1.09 1.56 l 6.12 11 PAHROC PASS 20 '20:22:29 '36.635 117.128 0.2 0.46 0.3 161 ACI 1.13 1.15 15.5 0.06 13 MESQUITE FLAT 21 2:-3:30 36.841 117.278 0.8 6.05 2.7 73 Bel 1.58 1.71 1.62 1.7 12.0 6.18 14 RYiBONE CANYON 21, 2:14:41 57.113 115.216 1.4/ .510 ' 1.5 240, 130!1.79 1.89, 1.81 1.7 6.8 0.17. 12;LOCWR PAI4RANAGAT LAKE Sw 21 .18;7:9' 37'.920 116.137, 0.5s 1.56 1.9 119, AC! 1.39, 1.46 24.9 0.13 12 REVEILLE PEAK NW 22 14:41:38 37.174 116.690 0.8 14.49 1.4 144 BC! 1.16 1.12 4.3 0.18 13THIRSTY CANYON IN 22 19:25:47 37.161 116.685 0.5 7.12 6.6 154 AB! 1.66 2.01 1.59 3.9 0.14 14 THIRSTY, CANTON NW 22 22:21:50 37.318 117.522 1.0 7.84 3.4 146 BC! 1.02 0.97 0.98 13.7 6.20 16 TULE CANYON 24 21:17:24 35.878 116.911 5.1 0.19 3.6 DO1 1.72 2.19 ,I1.73, 1.2 10.4 6.11 8 WINGATE WASH 24 22:20:23-37.083 115.268 9.4 16.34 % 9.4 277 DOI 1.37 0.434 2.1 18.8 6.12,.5 BUCKBOARD MESA 24 23:58:50 "36.855 116.295 0.5 7.29 0.9 112 AB! 1.37 0.75 1.6 2.2 0.09 12 GEORGES WATER 25 1:48:51 37.214 116.753 0.2 -4.82 6.2 127 ASI 1.45 1.84 1.07 1.3 7.9 0.08 19 SPRINGOALE NC 25 18:26:48' 37.058 114.969 1.8 11.33 2.3 261 00! 1.87 2.22 1.62 1.8 23.6 0.15 5 DELA•AR-3 SW,, 25 21:54: 0 36.830 116 320 e.7 0.44 0.7 83 BA! 1.22 6.47 3.7 0.20 12 GEORGES WATER 26 6: 1:38 37.479 117.878 1.2 4.38 3.6 171 DC! 1.11 6.95 1.17 1.4 6.5 0.13 9 CHOCOLATE MOUNTAIN 27 !22: 4:35 36.836 116.276 2.4 12.49 1.5 272 001 1.22 0.35 2.0 5.2 0.153 8 GEORGES WATER 28 1:23:17 38.574 115.982 0.4 12.92 0.7 167 AC! 1.11 1.22 1.18 1.2 9.8 8.10 i1 NIAVI WIASH 28 17:51:49 37.117 116.019 1.6 4.70 -, 2.8 162 DCI 1.07 0.83 9.2 0.20 12 YUCCA FLAT 1' ! I SW A h. "'7'7 •,"'A •" I I -. ý '% , , , .ý - 1991 LOCAL HYPOCErER S4MSARY,- SM EARTHOUA.id STANDO STAND AZI 000 DEL- RMS IN DATE - TIME'" LATITUDE LONGITUDE ERROR DEPTH ERROR CAP 12S MACNITUOE WIN RES. PH. U.S.G.S.'," (DEG., N) ESTIMATES '(UTC) • (DEC. W) H(KW) (KM) Z(KM) (DEG) Uco JUN 12 -1:6,0:12 37.218 117.347 6.2 7.52 ',994 A8I 1.18 1.11 1.6 12-2 6.05 11 GOLD MOUNTAIN 'I'. 12 .1:38:19 36.736 117.280 0.4 10.42 0.7 '128 ABI ,1.28 1.57 1.22 1.4 9.3 6.07 15 EAST OF SAND FLAT 2 2:59: 3 37.217 117.346 0.4 7.56 1.3 94 ABI 1.52 1.65 1.6 12.2 0.14 16 COLD MOJNTAIN 2 3:16:22 37.217 117.353 0.4 7.26 11.3 95 ABI 1.28 1.16 1.6 12.6 0.13 16 COLD MOUNTAIN '2 5:'5:44 37.218 117.352 6.2 7.33 6.6 95 ABI '1.31 '1.38 1.6 12.4 6.05 I COLD MOUNTAIN .2 6:14:15 37.218 117.348 0.3 7.46 0.5 152 Act 11.26 1.20 1.12 1.6 12.3 68.5 II COLD MOUNTAIN :3 .2 7: 6:)8 37.218 117.344 0.5 7.32 ,1 93 Atl '1.26 1.30 1.6 12.0 e.14 14 GOLD MOUITAIN 2 26:39:55 36.676 116.275 0.4 9.20 0.7 144 ACI 1.21 0.81 1 6.58 6.10 15 STRIPED HILLS 3 6:47:37 J7.265 115.239 0.4 3.01. 107 CCI 1.54 1.52 1.8 11.6 0.15 17 ALAMO-' - 3 16:21:52 36.624 116.295 -1.0 8.34 0.9 1 " Act 1.18 0.90 1.3 4.7 6.15 15 SKELETON HILLS 3 21:52: 8 37.295 115.237 0.8 8.59 2.9 .113 881•1.36 1.47 1.31 1.5 14.7 6.14 9 ALA.AIMO,-', " , .I 4 o,8:48: 3 '37.518 115.618 0.9 1.40 2.6 1166 .ACI 1.32 1.42 1.47 1.0 8.5 0.11 9 M4ITE RIVER HARROWS 4 16:57: 2 3793 '116.872 6.4 6.03 0.6 ;99 ACI' 1.24 1.08 61.94 1.5 14,3 0.15 15 SPRINGDALC'•. 1117. 265 4 19: 6:44 37.153 0.5 7. 0 1.6 89 ACI' 1.05 1.31 0.99 1 17.0 0.14 15 BONNIE CLAIRE W 5 2:41:52 37.329 115.015 "1.2 1.87 2.1 182 610 1.38 1.12 1.4 '9.1 0.13"9 ALAiMOSLES - 5 10:34:43 -37.214 117.356 0.4 5.77 1.5 143 ACI, 1.14 13.6 0.08 16 COLD MOUNTAIN 5 16:34:52 37.217 .117.356 ,0.2 6.21 6.7 141 AC! 1.66 '1:18 1.3 12.8 6.63 '7 COLD MOUNTAIN 6 6:23:41 37.799 116.697 0.4 5.23 '3.9 121 BC! 2.28 3.02 '2.34 2.3 16.1 0.15 21 STINKING SPRING SW 7 4:14:56 37.017 116.*153 0.5 1.43 2.7 211 '6010• .97 '6.69 7.1 6.09 11 TIPPIPAH SPRING 116. 148 - 1.17 7 6:51:33 37.024 116.695 0.3 4.65 1.1 112 A814 1.34 1.3 7.4 0.12 19TIPPIPAH SPRING 7 11: 4:24 37.796 .116.588 6.5 1.83 1.9 125 DCIt'1.61 1.80 1.73 2.1 15.8 0.17 15 STINKING SPRING SW '7 ;11:43:27 37.881 0.6 0.58 8.7 193 ADI 1.47 1.44 16.4 0.11 12 STINKIING SPRING SW 7 14:60:13 -37.e24 ,116.150 e.5 2.23 10.9 111 A,1 1.02 e.75 7.2 0.13 14 TIPPIPAH SPRING 8 3:48:50 -36.876 ,116.693 1.1 0.87 6.9 271 Dor11.13 0.93 6.56 S10.6 0.11 16 BEATTY UTN 8 ,7:27: 7 37.800 116.196 C4 "'.22 6.5 126 ACI 1.64 2.43 1;64 2.1 16.2 0.13 16 STINKING SPRING SW 8 13: 4:14 .36.701 •116.998116.1111 0:4 '4'.15 3.2 145 acI, 1.10 0.65 1.3 14.2 6.16 16 CAMlP DESERT ROCK 8 14:56:10 37.103 116.993 6.2 6.31 1.0 49 ACl 3.07 3.44 2.9 13.8 0.11 42,SPRINGDALE SW 8 15:-3:35 37.,96 116.993 0.5 4.41 3.9 lei DCI 1.11 6.81 (.80 13.2 0.15 14 SPRINGOALE SW 8 015:12:48 '37.199 '116.994 '0.4 0.54 .e.7 162 acIr 1.53 1.33 1.44 1.7 13.5 6.16,17 SPRINGOALE SW, 8 16: 9:42 '37.106 60.4 1.77 1.5 104 ACIU 1.63 1.49 '1.45 1.7 14;3 0.12 15 SPRINGOALE SW: 116.112 4+ 8 :17:13:35 -36.768 ,0.3 2.37 80.8 11e - ACF 1.27 1.04 1.35 ,1;3 14.5 0.88,13 CA•lP DESERT ROCK -8 -18:15:49 37.017 '116.154 ,0.5 -'1.96 53.6 216 DOI' 0.99 ? 0.68 7.1 6.08,16 TIPPIPAH SPRING 8 21: 8:47 37.187 116.993 8.4 4.47 3.6 104 DCI 1.14 0.91 0.96 .14.3 8.11,15 SPRINGOALE SW 118.246 6.7 8.04 6.8 ADI 1.67 1.2 5.0 1W 9 '%6:42:32 ,36.693 6•'.6 216 0.85 6.12 12 SPECTER RANGE 9 ,5: 7: 7 36.696 116.254 6.6 7.98 216 ADI 1.18, 0.86 1.1 " 5.4 0612 15 STRIPED HILLS 9 5:23:45 36.697 116.253 0.5 7.82 8.5 210 A01 1.16 '1.09 1.1 '5.4 6.69 14 STRIPED HILLS 9 5:46:16 37.106 116.997 0.4 4.74. 3.1 68 BCI 1.76 1.76 1.8 14.2 0.12 17 SPRINGOALE SW 9 11: 7:13 36.694 116.252 0.4 8'18' 6.8 '137 ACI 1.16 S.o0.72 5.7 0.12 16 STRIPED HILLS ,j ,ý~~~~~~~~~~~~~~ ~ ~~ ~ ~ t o .-- n oý ...... - A 1991 LOCAL HYPOCENTER SU.MARY - SG8 EARTHJAXES DEL- R4 #N STAND AZI OOD WIN RES. PH. U.S.G.S. STAND GAP 12S UAGNITUOE ERROR DEPTH ERROR EST.UATESMLh iLyv ILc (KU) (SEC) QUIADANGLE- TIME LATITUDE LONGITUDE (DEG) , UMco Ud DATE - (DEG. W) H(KU) (KU) '- Z(KU) (UTC) (DEG. N) 1.: 225 BOI 1.35 1.14. 5 18.7 0.15 I ,HEAVENS WELL 115.619 2.1 e.79 1.2 1.46 I.'6 17.9 6.99, 15 STONEWALL PASS 36.625' 134 AC! 1.34 SW JUN 9 11:49:40 117.248 0.3 6.71 0.4 1.49 1.41 1.'6 6.4 0.16 IlLOWER pAHR4&NAGAT LAKE 9 13: 7:52' 37.462 1.6 -e.54 0.6 237 B6I 1.52 7.2 0.13 15 TIPPIPAH S;6ING 115.233 176 ACI 0.93 0.72 9 13:14:56• 37.124' 116.152 6.6 1.63 1.3 1.383 1.4 7.3,0.13 14 TIPPIP/Ji SPRING 9 13:28:56 37.020, 0.53 3.45 j 2.6 III A J!1.361 "6.99 7.9,6.14 15 7IPPIPMH SPRING 116.149 116: AN! 1.14 9 15:25:32 37.021' 118.141 6.4 2.63 1.0 9 18: 9:25 37.629 6.70 S10.2 6.24 19 HIKO NE 1.4 117 BC! 0.95 115.841' 0.57, C.72 0.83 * 13.4 0.18 12 SPRINODALE SW 9 25: 6: 6 37169 0.7 4.32 6.1 102 CCI 1.02 7.4 0.13, 15 TIPPIPAH SPRING 116.998 113 AB8I.02 0.95, 16 3:28::. 37.699 116.148a 0.4 2.435 1.0' 12.9 0.16 16 SKELETON HILLS 37.026 189 601 1.02 0.26 0.65 16 6:11:45' 116.255 0.) 4.97 3.2 1.48 2. 0 7.7 0.12 13 TIPPIPAJ SPRING 16 15:25:46 36.551 0.5 2.48 0.9 114 A,81:1.66: 4 8.4.0.21, 14 LCoER PAP-4AHAGAT LAKE SW 116.'144 194 60! 2.52 16. 15:40: 6, 37.025' 115:209 6.86' 1.7 10 15:45:47 37.095 • L 6.5 6.14 13 TIPPIPAH SPRING, 1.07 1.1 6.08 0.5 250 601 6.75 1 6.9 6.16 13 MAkRUDER WITH 116.162 92 ABV1.•1. 1.87 1.76 16 16: 9: 4 37.615 117.563 8.4 4.39 1.3 o.01 7.3 6.63 6 STRIPED HILLS 10 19: 4:44, 37.475 0.7 1.99 0.9 248 AD!'1.77 0.17 14 SPRINGOALE SW 116.264 1.36 1.22 1.32 4 14.0 11 4:23:48 36.677 6.5 4.65 4.5 163 0C1 7.2 0.14 13 TIPPIPAH SPRING 116.996 ASI 6.86 0.75 11 4:23:53 37.164 6.5 4.22 1.8 115 6.46 7.0 0.67 16 TIPPIPAH SPRING 37,29 116.149 ADI 6.93 "1i 7:41:56 116.155' 0.4 1.45 1.4 287' 11 12:12:41 37.015 12.3 0.65 13 COLD MOUHTAIN 94' ASI 1.34 6.15 1.35 6 348 0.2 7.48 6.5 •8 10.2 6.16 17 LEHEBE CRATER' 117. 125 CI! 1.73 1.62 11 14:16':56 37,218 117.396' 6.5 0.17 6.6 1.06 .6 7.6 0.13 16 TIPPIPAN SPRING 5:21 37.082 115 ABI 1.18 11 15: 116.145 0.4 2'99 0.8 1.19 1.65 14.6 0.19 IS SPRIHGDALE SW 11 15:38:54 37.030 0.6 4.35 5.6 1s3 cci 1.36 5.9 0.12 9 TIPPIPAH SPRING 116.996 0.93 6.59 11 18: 4: 9 37.184 1.6 0.50 1.3 241 80!6 5.8 0.12 13 wHITE1T£• MC•LNTAIN 116.171 1935 AD!'1.22 1.21 1.73 .4 11 19: 0:42 37.612 117.456' 0.7 7.79 0.8 35.823 11 23:54:36 0.89 0.91 21.5 0.07 17 SPRINGOALE 1W 6.2 0.76 6.3 133 ACI 1.355 22 CATTLE SPRING 116.9615 63' BCi 2.87 3.10 2.IV .8 12.6 0.15 12 1:23:59 37.190 0.4 6.74' 6.8 11.7 4.14 14 CATTLE SPRING 115.852 1.34 1.29' 12 5:26:53 37.429 6.4 1.36 11,3 76 AC! 26.7 0.11 19 SPRINGOALE UK 115.843 87 CCI 1.37 1.13 1.19 12 7:15: 9 37.424 116.952 0.3 4.17 5.6 1.69 .1, 24.5 0.14 9 GREGERSON BASIN 12 8:26:43 37.190 1.6 10.83 3.8 237! 801'175 2,.9 16.2 6:l6 14 INDIAN SPRINGS 1M 114.825 155 ACIl1,77 1.79 1.92 1 12 11:59:56 37.279 115.649 6.5 1.58 1.5 12 12:58:,4 36.628 68 oCi 1.56, 1'. 64 1.4 11.7 6.17 16 CATTLE SPRING 115.a52 0.4 4.69 2.7' 1.26 1.29 1.4 15.7 0.28 12 INDIAN SPRINGS 12 13:44:57 37.418 1.1 4.81 8.2 148 CC! 1.46 2.2 13.2 0.15 17 FRDENCIAN FLAT q 36.609 115.671 BCI 2.26 I .86 12 18:32:43 115.948 0.5 4'.87 3.6 128 1.32 1.5 13.4 0.12 15 FRDENCHAN FLAT 36.850 197 AD! 1.39 12 18:46:22 115.942 6.6 6.8" 1.8 6.67 6.9 6.11 16 TIPPIPAM SPRING 12 18:47:22 36.853 1.41 7.5 265 Col 0.92 21.6 0.12 58 SPRINGOALE NWN' 116.158 6.6 56 AC! 2.81 3.27 3.0 12 19:45:45 37.014 116.955 e.2 5.78 6.7 12 22:39:27 37.193 6.7 0.12 13 TIPPIPAM SPRING AD! 2.05 1.2 203 1.26 0.98 0.9 0.16 10 INDIAN SPRINGS 116.166 6.6 8I0' 1.37 1.28 18.5 13 1: 1:32 37.013 1.20 3.8 293 0.99 19.7 0.25 7 HEAVENS WELL, 6 36.615 115.627 1.4 295 D00 1.43 1.23 1.6 13 3: 2: 4.34* 0.75 14.1 6.15 17 SPRINGDALE SW 4:3 36.711 115.591 5.2 104 AC! 1.34, 6.58 15 4: 116.996 6.4 6.63 0.6 1.81 *1.9 13.7 0.14 19 BGONIE CLAIRE SE 13 13: 4: 1 37.105 103 ACi V175 TV 117.8e1 6.5 1.32 1.3 1.54 12.7 6.67 15 I.ESOITE*FLAT 13 -13: 8:37 37.182 1.0 165 ABI 1.23 1.19 117.138 6.916. 6.69 13 13:12:5a 36.631 0.62 1.03 6.6 6.11 1i kGRUDCR 11T 6.6 1,4.37. 1.3 131 AS! 0.96 1.1 0.11 9 TIPPIPAN SPRING 16:48:41 37.473 117.561 1.32 IIs5 1.0 13 116.224 3. H' 0.7 149 'ACI 13 18: 3:11 37.028 9 ' . - 2 1 199 1 -LOCAL HYPOCENTER SUMMARY - SGS EARTH AXES, 94 DEL- RJ5 jN STAND STAND- AZI 000 DATE - TIME LATITUDE ,LONGITUDE ERR•R DEPTH 'ERROR' CAP ',12S MAGNITUDE ESTIMATES uRN RES. PH.'U.S.G.S: ¶(UTC) ' 1(DEG. N) ,(DEG. W) H(KU).t, (KM) z(Iol) (DEG):- ' i~ca Md MLh MLv MUL4 (KM) -(SEC) OUADRANGLE' . 1% JUIM14, 2:36:58 36.626 115.649 e.9 6.4 154 "CCI 1.67 1.24 1.54 1 .6 16.3,8.18 12-INDIAN SPRINGS NW +14 1 3:4a:37 36.680 115.611 3.2 S3.1666.86 - 294 COI 1.51 0.99- 0.922- I .7 17.9.0.23,5 9 HEAVENS WELL -14 --6:24:54' -36;738 _115.963 0.36 0.5 ',55 881 2.66 2.25 2.16 2 .1 8.6 0.17 40 MERCURY,,-, 14 7:28:26 36.376 117.462 e.g 7.0 4.5 236 901 1.31 1.25 1.13 32.4 0.09 11 PANAMINT BUTTE 14 -12:29: 8, 37.121 *'115.235 2.1 4.58 2.6 239 801 1.29 1.21-'1.20 1 .4 6.8 0.17, 8 LOWER PAHRANAGAT LAKE SW 14-.,19:19: 4 137.674 ,114.883 .-0.5 6.70 0.8 156 ACI 1.29- 1.23 1.36 5.4 012 11,PAHROC SPRING .14 20:21:19, 37.042 :,117.457 6.6 5.57 "i2.4 147 SCI 1.39- 1.48 1.55 1 .2 -11.6 0.13 13 USDEHEr CRATER .14 -26:22:35 37.:42 ,-117.459 0.3 6.69 1.6 ,152 ACI 1.19--- I.64 1.20 1 .2 11.1,0.07 11 UBHDIErCRATER :15 - 2:.5:37, 36. 635 1,116.335 , J.5 ,3.57 6.5 ý4184 ADI 1.29 1.39 1.36 1 .4-, 1.2,.611 26 STRIPED HILLS 15 2:38:48 36.641 115.654 2.3 9.69 5.1 176 CCi 1.95 1.95 2.65 2 .6 15.5 0.44 11 INDIAN SPRINGS WM 15-ý'8:22:4aZ 8 2 4 9 9 - CCI 1.33 t-1.68 1 . ! . 6.0 12 REVEILLEPEAX ,15 15:47:51-; 37-924 116;132 0.3 3.68. :126 1W 37.190 1,117.395 0.4 •6.8.3 2.1 124 OCI 0.85 0.82- 0.98 S,17.3 0.68- 7 WEST Of COLD LTN 5r.5 -1• I I ,, ' _' " 1,16 9 -, .. 0. S15 .19:14:39+37.107 S116.994 6.6 4.23 5.4 104 CCI 1.13 0.88. 0.85 ,14.4 6.17,11 SPRINOGALE SW :15 21:46:48 1,16 •-4:36:27'-,37.184.37.217 ,117.354 ,;6.5 4.81 2.4 88 SCI 2.04 1.78 2 .• 12.6 6.12 ý14,CGOLD IE4OTAIN "116.998 6.3 4.36 2.6 193 OCI 1.51 1.5411.30,11 .8 -13.9 0.10,16 SPRINGOALE SW' - 294 001 1.56 17 6:24:33 36.639 115.618 9.4 2.54s 4 1.67 1.47 1 .5 18.2 0.26 9 HEAVD•S WELL ,•17 :4:17:47; 36.636 ,*115.615 ,1.3 4.37 ,8.9 227 VýCOI.1. 5 1.13, 1.37" 1.5 18.6 6.18412 HEAVENS WELL' -.17,m2:49:45-,37.219 ,r017 3 5 1 4-6.4 6.26 1.5 87 ,BI1 2.63 2.09 2 .11 12.3 0.12,16 GOLD MOUNTA.IH. ,17 20:53:4a6,37.219 1,117.336 6.7 7.66 2.0 ....91 91 1.1g 1.36,1 1.67 11.4 0.17,11 COLD MOCUNTAIN ,17 22:38:17-137;220 !,117.354 0.4 7.54 '1.0 153 ACI 1.16 1.43, 1.05,, 12.2 0.09 11 COLD NGIMMTAPIN 17 -22:51: 3,36.622 .115.650 , 1.1 5.72 -5.8 , 153 COCI1.53 1.03 1.41 1 .5 416.5 6.24 13 INDIAN SPRINGS J17 23:47:45 37.281 117.545 6.4 6.65 1.3 88 AS8 1.19 1.25 1.4 1 .5 16.5 6.13 14 TULE CANYON ,;117.355 6.30 * 7.41 j 6.8 95 PA.| 1.4e 1.41 1 .6 12.6 6.67 13 GOLD MOUNTAIN :18 0:51:33, 37.218 4 4 18 , 9:58:5e 37.631 ,1116.1 6.4 2.77 40.8 x116 AB1 1.19 1.18 1 .2;. -7.7 0.14 15 TIPPIPAHSPRING 18 22:59:160 37.114 0116.445 6.20 7.77 0.7 ..54 ABI 1.99 142 '2 .2 10.2 6."9 31,TINDER,MTN " 19-.-:4: 3:23-,36.625 ;,115.634 1.3 6.35 1.4 221 9OI 1.77 1.39 .1.61 I .6• 17.5 0.14 12 INDIAN SPRINGS NO ;19 6:49:22 ,37.218 A M17.338 .0.6 *9.39 1.5 92 ABI 1.19 :1.28 1."g 1 .6ý 11.6 6.15 11 COLD MIOCUTAIN '.4 -7 19 17:22:56 .37.296 117.594 6.3 8.02 6.6 82 AAI 1.42 1.74 1.40 1 .4 7.9 6.68 14 TULE CANYON 19 18: 1: 5,- 37.103 • 4.9 4163 -DCI 1.49 1.52 1.51 1 .7 13.9 0.18 14 SPRINGOALE SW 2 2 2 3 9 7 11116.996 6.6 '4.46 -194 :3 : "S3 .183 1;116.999 6.7 4.91 4.3 -115 BCI 6.85 0,.41 4 0.46 13.6 0.12 g9 SPRINGOALE SWi, -' 2,. 2:45:47.,-36.637 1115.639 ,60.9 1.67 S2.2 222 BDI 1.67 1.35 1.49 2 .6 16.6,6.16 10 INDIAN SPRINGS NW 26 5:28:32A37.216 117.352 0,6.3 7.94 .6.8 .95 .ABI 1.68 1.81 2 .6 12.5 6.68 15 COLD MOUN4TAIN 26 6:12:13- 37.218 117.343 6.6 6.95 1.8 93 98!, 1.24 , - ,1.13 1.•3 * 11.9,0.15 13 COLD MOUNTAIN,ý, 26 17:42:47' 37.137 115.239 2.3 1.90 2.8. 223 DCI 1.36 1.26 1.28 1 .0 5.8 0.14 7 LOWER PAHRANAGAT LAKE WV 28 18:59:59- 37.217 S117.351 6.2 7.91 ,6.7 *88 ,P81 1.90 1.32,,1.95 2..6 12.460.67 15 COLD MLUNTAIN 20 A19:, 6:14 - 37.221 1117.344 0.7 7.46 2.1 92 -98160.91 21.37 .6.97, 11.86.16 16 COLD MOUNTAIN 26 26:15:36 36.730 S115.792 e.7 .9.18 6.6 249 P.11.I`.'15 , 6.97 4.3 6.67 i8 MERCURY NE', * 21 " 1:55:43' 36.266 !116.455 6.3 0.52 6.4 128 ACI, 1.25 '.m 1.31 15.4,0.08 12 DEATH VALLEY JUNCTION S21 4:53:28 37.221 J117.345 -6.4 8.69 -1.0 93 .I1 1.26 1.24 0.95 11.8 0.68 j,9 COLD MOUN4TAIN 21 4:54:48 37.223 117.357 6.8 7.81 2.6 155 DCI 1.09 0.79 12.4 0.13 9 GOLD MOUINTAIN 21,1 5: 6: 3 37.220 :-,117.357 6.5 .17.28 .1.1 '155 ACI 1.90 1.24, 1.61 :, 12.6 0.68 9 COLD MOUNTAIN n., 21 -5: 6:33 37.222 117.344 ,S.6 -8.72 1.3 . 93 .ABIPI.18 1.20 1l.66 r11.7 6.11 9 COLD MOUNTAIN 21 5: 2:53 37.217 117.344 Z .3 7.58 0.6 151 ACI 1.41 1.45 1. .6 12.6 0.65 11 COLD MOUNTAIN 21 5:12:19 37.219 117.335 6.6 , 7.76, ,1.7- 91 -ABP 1.65 1.18I-.- 2..6 11.4 0.15 12 COLD LOUNTAIN '-3 1991 LOCAL HYPOCENTER SLUMARX -,SC8 E"ARTHQUAXES j, . DEL-: R INSI STAND STAN• AZI COO r DATE - TIME LATITUDE LONG ITUDE ERROR DEPTH ERROR 125 MAGNI TUoE ESTIUATES, MIN. RES. PH. U.S.G.S. H(KM). (KM) GAP. Uko "WI (QC) ,, (DEG. N) (oEG.w)W Z (KM) (DEG) ULh:: ULv MLc (KM) (SCC) QUADRANGLE JUN 21;, 5:13:17 -37.21901 117.356 6.5 6.11, e.9 155 AC! 1.14 1.06 12.6 8.06 OGOLD MOUNTAIN 6.8 96 21 7:35:49 -37.226 117.334 ABI 6.11 11 MXOUNTAIN 6.5 8.25 1.4 1.28 1.22 1.7 11.3 GOLD 21 7:33:52 37.216 117. 560 5.46 1.7 157 ACI 1.21 1.33 0.95 13.1 6.16 11 GOLD MOINTAIN 21 15:20:14 37.218 115.6335. 6.2 7.90 6.5 153 ACI 1.27 1.17 1.6 12.4 0.04 II COLD IJOUNTAIN 22 1:35:27 38.616 2.5 4.377.26 8.1 226 COI 1.49 1.14 1.37 1.5 29.9 :.67,. 6IINIAN SPRINGS 22 4~:S5.6' 115.774 2.3 3.1 163, 0CI6.9e 4a.84 6 1 GROOW IHEl + 22'; 5:38:-5 '36.628' 115.6355 SPRINGS Nw 1.4 6.68 6.9'1.7 221 AD•I001. 0.87.61.42 1.01 1.34' 1.5w 17.4 6.15 IS,INDIAN 22' 8:11:52 '37.021'' 116.148 6.4 2.34 III 6.71- 7.4 6.9 I1 TIPPIPAN SPRING 22 10:49:58 37.221'' 117.346 :.7 9.41 151 ACI 2.3 1.12 6.58 11.9 0.12 9 GOLD 1OUITAIN 22" 18:24:10 "37.089 117.198 0.5 1.89, 1.7• It.* 18.33 125 2.15 2.0 0.15 16 U80t(BE CRATER 22 19:12:19 37.125 115. 208 1.4 1.3 252 801 1.62-, 1.56 1.44+ 1.8 5.1 1.17 II LOER PAHRANAGAT LAKE No 235, 2:46:33"-36.516', 116.590 6.6 6.27., 2.9 166 SCI 1.73 1.167 1.78 1.9 16.7 0.13 14 LEELAND, 23 23: 31:9' 37.400 117.338 6.7 9.37 1.4 92 A81 1.65 1.24 . 1.21, 1.6 11.6 6.15 10 GOLD MOUNTAIN 115.217 1.0 6.84 3.3 176 0CI, 1.11, 1.24, .86 1.4 '14.7 6.69 ,,7ASH SPRINGS, 1, 24 1:43:49 36.599., 115.626 4.3 2.48o., 222 COI 1.97 1.77, 2.1 ,26.1 6.2 9 INDIAN SPRINGS SE 24 7:53.:44 J7.134 115.241 1.3 0.52 0.9 224 801 1.56 1.34 1.07 1.6 6.1 0.13 It LOWER PAHRAN.GAT LAKE NO 2Sý, 1:42:48 36.644,.. 115.612 1.6 2.05 2.2 228 801, 1.37 1.11 18.6 0.11 7 HEAVDES WELL 25 2:12:24 37.35904: 117.25,3 1.5' 6.96 1.6 195 DOI 0.96 1.4 9.9 0.21 8 NGUNT JACKSON 25,, 2:39:14 37.376, 117.695 0.6 4.65 5.9 142 1.35 1.5 1.6 18.5 0.12 8 SYLVANIA LK)*ITAINS 25. 3: 4: 8,,37.234 117.717. 4.3 2.5a 4.7 234, COI,001,1.16 1.37 6.92 1.08 1.2 6.2 0.24 6 HANGING ROCK CANYON 25 15:18:32 34.768, 116.274 6.7 6.48, 1.6 133 001 1.57 0.29 2 2.9 0.12 10 CGERGES WATER , 25 16:59:•8 37.922 116.131 0.3 Aci 6.65 15 NW 2.88 2.2 120 DCI 1.68 1.88 2.3 24.7 0.11 REVEILLE PEAK ' Y A.,' 25 21:22: 4ý,37.922, 116.134, 6.5 2.93_, 5.0 120 1.77., 24.90.13,I1'REVEILLE PEAKNM 26 5:,2:15,37.923 116. 15 0 6.4 3.60. 120 CCI 1.61 1.88 ,2.0 24.6 6.1 I1I,REVEILLEPEAKiNW S+ r 27 6:54:55, 37.102 116.738 0.5 0.41 0.4 13a, AI-1.34 I.ni 1.1 5.1 0.12 IITHIRSTY CANYON SW 27ý, 7:38:59 37.1W5 116.738 8.2 0.14 9.1 131, ABI:-I856 1.25 1.0 • 4.7 6.85 17,THIRSTY, CANYON SW 2. 27 It: 6:43 36.639-, 115.654,,, 4.0 0. 15,.: 5.3 290,,6 CD1 1.73, 1.47 1l.55 1.6 15.3 6.18,1, INDIAN SPRINGS NW 27 19: 0:42 36.628 117.144 6.5 7.77 1.9 168 Asl 1.19 1.74 I..'2 1.4 12.2 6.09 11 MESQUITE FLAT 27t 22:16:10 36.805 115.847 6.7 6.43 2.9 219_, 801 ,1.286 %0.90 12.7 a.07 6 FREHMcI',AN LAKE SE. 27. 22:56:19,•36.799,ý 115.859_, 6.8 7.58 1.6 216 ADI 1.05 6.86 12.4 0.05 6 FROCHIA LAKE SE 5.6.8.. 28' 5:11:45536.776 115.505 8.9 348 DOA, 6.82 68.6 0.28, 7 TIM SPRING ',, . . .12:44:47- 1.86 'A' "28 37.185 116.331 1.4 4.82,1 178•. DCA2 6.81 4.660.09 8A,AMMOIA TANKS 29. 3:55:11-'36.7355, 116.1006 4.7 2.92e 270 CODA 0.67 14.7 0.27,10,CAMP DESERT ROCK 29 9:19:24 37.092 117.009 2.3 8.65 3.2 286 BOA 1.18 12.5 0.13 11 BONNIE CLAIRE SE 29 10:35:40 36.594 115.864 2.59 289, ADA 1.15 27.6 0.09, 4 MERCURY SEr 30 5:52:52 37.208 117.588 0.5 8.04e 6.7 181 ADI 1.14 1.42 1.23 5.8 6.68 10 SAND SPRING JUL 1 5:17:45 36.725 116.234 1.5 4.36 0.9 253 801 1.15 1.65 6.60 0.9 4.6 0.14.,1SPECTER.RANCE W 1 5:18: 5, 358.733, 116.280 e.9 3.38 e.9 172 acI 1.68 1.31 0.48a 6.8 1.2 0.17A13 STRIPED HILLS' 1 17:29:22 36.816 115.812 0.8 1.26 1.6 203 ADI 1.67 6.9a 13.6 6.13 12 FRENCHMAN LAKE SE 1 18:30:11 37.587 117.456 1.2 3.69. 216 CoI 1.00 6.87 6.76 16.7 0.11 8 ,o4T(Ezu PEAK SW 1 20:33:31 37.615 116:556 1.1 21.59 1.9 127 681 1.50 1.64 15.2 6.16,10 THIRSTY CANYON SE 2 5:13:25 36.815 115.b28, 1.4 0.96 1.2 217 801 1.47 1.09 1.40 1.5 15.5 6.17 11 FRECHMAN LAKE SE 2. 2 12: 7:47 38.886 118.219 0.6 4.79 I.e 121 AI . 0.57 4.5 6.10 12 UINE MTN 2 21:58:18 36.670 116.219 1.3 0.96 1.0 244 801 6.96 . 0.76 9.4 6.14 II SPECTER RANGE NW :4 'A -Jo '1 /* i - " "" J V * 'Ar - - EARTHQUJAKES 191LOCAL HYPOCENTER SIML&ARY 50 DEL-. RUS IN OO0 ' S TN;w STAND AZ UIN ' RES. PH. U.S.G.S. GAP 12S MAGNITUDE ESTIMATES, LONGITUOD ERROR DEPTH ERROR ILy ULc (KU) (SEC) QUADRA•GLE DATE -'TIME- LATITUDE (DEG) U,ca ULh t." ((UTC),(DG.E N) (DEC. W) H(KIM) (KM) Z(KU) 0.14 12 SPECTER RANGE'NW' D011.42 0.89 1.2 7.8 1.1 0.85 e.9 232 1.6 5.2 8.11 32 PINNACLES RIDGE "JUL 3 17:44:29 36.680 116.233 82 AAI 1.41 1.49 1.21 116.421 6.2 7.67 0.5 1.42 1.6 12.2 0.68 12 COLD MOUNTAIN "4 -0:22: 2 36.997 0.8 152 'ACI 1.44 UTH ,' . ,, 37.218 117.348 6.3 7.21 0.49 4.3 0.69 I1 TIMBER 4 0:29:43 8.46 e.g 175 6.990ACI ' 13 PIINACLES*RIDGE 8:51 37.a01 116;416 6.6 0.6S 5.2 6.08 "4 1: 0.5 8.64 0.6 165 'ADl 1.11 ;4.6 0.14 14 TIUBER MTN 4 -2:56: 8 36.997 116.421 9.62 6.9 153 ADI 1.04 0.71 "14 3:13:41 37.601 116.416 6.7 5.4 e.06 17 PINNACLES RIDGE 168es! 1:13 .68 RIDGE 116.424 6.3 7.58 e.4 6.89 6.8 5.6 6.06 12 PINNACLES 4 5:51:38 36.997 6.5 269 AD| 1.34 FLAT 36.997 116.428 6.4 8.27 1.71 1.9 12.5 0.67 14 mESoWiTE 4 5:13:35 6.2 '2.36 0.8 lee ACI !.66 8 SPECTER RANGE NW 4 11:42:39 36.639 117.136 901 6.55 8.6 0.17 1.7 3.43 4.3 237 35.6 0.14 10 PANAMINT BUTTE 4 12:57:32 36.673 ,116.236 241 COI 1.32 1.21 1.37 17,497 1.6 2.25 6.6 1.7 14.1 0.68 I1 STOVEPIPE WELLS NE 4 23:3e:20 36.371 1.2 102 AOI 1.61 1.59 1.73 S1:45:16 36.629 117.122 6.4 10.29 6.6 10.19 1.1 128 ABI 1.23 1.50 7.2 0.11 IS IfPPIPAH SPRING 17428117.803 .6.3 0.25 6.5 95 MBI 21.7 0.65 'a SCRUGHAM PEAK 63:25:12 15 NW .37.095 116.194 2.6 8.24 4A1 340 WDA 24.0 6.16 SPRINGOALE 6 12:35:23 133 BCA' 6.39e.52 7.1 0.12 13 AMARGOSA FLAT 37.211 116.495 6.5 7.88 3.6 ACA 7 16:25:49 1.6 '172 0.68 "16.9 0.14 8 THIRSTY CANYON SE 7 17:22:32 37.188 ý116.953 0.8 5.15 6.42 8.1 387 CREE( 7 17:36:59 36.492 116.152 3.7 COA' e.79 38.9 0.14 6 WEST OF FURNACE .7 23:18:31 37.611 116.581 262 6.74 INDIAN SPRINGS 3.5 17.47 COA 2.2 27.6 0.13 11 ,CI 2.17 2.76 SPRING 116.905 6.9 ,0.79 1.6 152 1.91 31.8 0.34 6 OREANA 7 23:22:56 36.389 COl 2.86 1.39 1.64 0.21 11 ***REGIOHAL*** 36.622 115.664 3.8 7.e00 223 2.0 37.2 8 22:"1:0 3e7 1.92 1.98 2.05 6.069 9 GOLD MOUNTAIN 37.977 115.231 1.9 '3.22* coI 0.94 "11.9 9 13:12:23 9.74 93 AI,1 .16 0.89 12.6 6.68 12 COLD MOUNTAIN 9 15:26:36 37.854 A114.454 0.5 9.7 1.19 1 13 0.3 8.31 e.9 95 ASI 1.28 9 18:26: 3 37.219 117.344 1.6 12.3 0.16 13 GOLD MOUNTAIN 18:30:44 37.215 117.351 9 8.11 1.6 94 '981 1.36 1.41 29.6 6.69 11 INDIAN SPRINGS e.6 0.95 1.18 6.9 0.67 6.7 218 AD! 1.41 1.4 16.2 0.14 '8 TULE CANYON 1 2:48:17 37.218 117.350 2 02 "1.12 0.91 SPRINGS. 115.638 6.7 2.09 1.6 82 Act 1.16 1.5 27.1 6.13 10 INDIAN 190 6: 7:28 36.607 OCI 1.62 1.36 1.66 9 PAHROC SUMMIT PASS .37.291 117.558 I.e 10.77 3.5 153 9.4 0.08 ' I 9:51:12 2 i.e ACI '1.66 '1.02 6.96 13.8 0.13 9 YUCCA LAKE ýi1 18:42:29 36.624 115.66 e.4 796 136 1.481 298 BOA 6.85 11 9:48:59 37.568 114.925 1.;4 8.8 0.54 U8GEORGES WATER 12 3:24:44 36.881 116.617 0.4 6.08 '99 0.15 37.2 6.069 INDIAN SPRINGS 1.40 6.15 16 CATTLE SPRING 36.821 116.290 1.7 3.22.' 293 COA 5.2 12 9:21:59 DCA 1.21 0.066 4 CATTLE SPRING -36.612 .115.749 1.3 -.0.07 150 5.1 12 '12: 7:48 1.66 6.31 7 CATTLE SPRING S.. 12:46:50 37.380 115.781 - 1.48 155 16.1 12 2.5 167 ADA 24.7 0.16 11 INDIAN SPRINGS '12 12:41:34 -37.380 115.774 ,1.9 8.44 CCA e.9e 115.810 '7.ee 9.7 191 DA, 12 13:1:11 37.379 '3.1 ! .68 3.6 16.7 0.19 52 INDIAN SPRINGS NW ,12 15:44:50 -,36.552 :115.720 3.17 -1.97 NW 0.3 1.30 2.1 45.2 6.06 11 INDIAN SPRINGS '2.03.9 15671 DCI*DCI 2.602.19 2.67 2.38 16.3 6.12 11 INDIAN SPRINGS NW 56.633 115.640 0.5 , 11.46 1.45 12 16:41:31 '1.1 158 ACI 1.51 1.20 28.3 6.05 6 INDIAN SPRINGS NW 12,,18:44:26 •36.628 115.642 0.9 .8.97 0.52 6.85 e.5 3.37* - 220 COI 1.97 1.8 7.5 6.11 9 TULE CANYON 12 20:38:41", 36.638 11 .642 'AB? 1.52 1.63 1.49 115.647 8.7 2.67 1.9 111 12.7 0.10 13 COLD MOUNTAIN 12 22:12:48 36.638 1.1 95 AI 1.23 1.16 1.12 37.296 117.617 0.4,1 7.59, 12 23: 8:30 6.68 18 BEATTY UTN 13 2:46:10 37.216 117.353 13.2 1.3 130 AB? 1.05 1.68 0.49 1.6 15.3 6.69 13 INDIAN SPRINGS NW 9.28 0.5 15 AC! 1.68 1.56 1.71 13 7:19:17 36.886 115.661116.725 6.50.3 -1 .84 13 21:11:32 36.627 ': Z7.'-' -'==== -- = -- - - I - z *.= - - "--- - - I --- -- .--. - 1991 LOCAL HYPFCENTER SLALARY - SO EARTHOQUAES STAND STAN D AZ1 000' DATE - TIME DEL- RMS IN LATITUDE LONGITUDE ERROR DEPTH 'ERRO RGAP 125S 4AGNITUDE ESTIMAT WIN RES. 3,-i (UTC) (DEG. N) (DEG. W) TWEv UMb PH. U.S.G.S. H (KU) Z(KM ) (DEG) Iica Md ULh (KW) (SEC) QUADRANGLE JUL 13 21:56:11 37:419 117.615 0.5 7.70 1.3 122 ABI 11.12 1.18 10.5e.e9 .MAGRUDE 14 3:58:57 37.109 116.994 8 uTN 5 0.6 4.19 5.2 105 1.71 0.70 0.79 14.6 0.14 14* 4:57:10 36.622 115.637 1.6 0.75 cci1 12 SPRINGDALE SW 1.8 220 801 1 .33 1.13 17.3 0.12 16 INDIAN 14' 6:59:55 36.716 115.831 1.4 7.00 8.4 233 DI I SPRINGS 1.41 6.85 1.15 1.5 30.1 0.18 I INDIAN SPRINGS NW 14 8:57:60 37.435 115.590' 0.6 0.65", 1.6 98 UCIl '.35 1.32 17.2 0.21"13 GROOM RANGE NE 5,. 14A 22: 2:33• 36,626 115.865 0.6 1.45' 1.7 153' AC! I .82 1.77 1.79 1.6 15.1 0.12 12 INDIAN ,SPRINGS NW 15 4:24:53 36.718t 115.886 1.6 1.85 2.6 145 DCI 1.44 1.03 16 1.29 1.4 7.2 0.26 14 MERCURY 3:59:21 36.768 115.258 0.6 4.18 1.6 165 DCI I .03 1.32 6.82 16 5: 2:48 37.225 0.9 3.1 0.16 16 GEORGES WATER 117.584 03 6.42 1.5 117 ABI 2 .26 2.82 3.1 5.6 16 5:19: 7 37.143 a.62 0.13 29 SAND SPRING 117.381 0.4' 1.1 1160 ABlt .13 1.32 1.15 16.3 0.11 16 8:44:31 36.832 115-425 0.7 7.60. 15 WEST OF GOLD MTN 205- COl 1 .65 1.13 1.63 1.8 42.9 6.14 13 DOG DONE LAKE 17 9:52:53 36.617 115-628 0.6 14.25 2.1 SOUTH 155' 8CII1.53 1.20 1.48 1.5 3e0.2 0.12 12 INDIAN SPRINGS 18 4:59:38 37.184 116.960 0.3 9.92 1.2 131 ACI41 36 1.69 1.49 2.1 21.2 0.10 18 SPRINGALE NW 18 8:28:28 J6.753 115.950 1.1 7.16 2.1 212 00I1 .16 0.41 0.93 1.1 18 10.2 0.12 7 FRECHMAN FLAT 12:38:44, 36.777 117.227 8.4 8.52 0.6 83 ACII .81 1.80 1.73 1.9 15.3 19 7:54:.9 37.105 116.738 0.2 0.14 18 FALL CANYON 0.22 0.1 132 ABI-I .583 1.60 1.23 1.1 4.7 6.06 19 7:54:51 37.105 116.737 0.3 0.28 16 THIRSTY CANYON SW 0.2 131 AB'•l .25 0.77 1.1 4.6 0.07 I1 THIRSTY 19 8:25:32 37.113 116.742 0.5 2.42 0.8 140 ACI 1 CANYON SW .39 1.04 1.09 1.2 4.1 6.12 14 THIRSTY CANYON SW 19 12:46:21 38:612 115.638 2.8 0.71 1.8 292' COI I .33 1.31 1.24 1.5 29.4 0.12 I1 c_,o 19 21:51:1121:53: 7 38.629 117.124 0.3 2.78 INDIAN SPRINGS 1.7 102 ACI I .49 1.53 1.55 1.6 13.9 0.08 14 STOVEPIPE 36.629 117.117 0.6 7.69' 4.2 101 88!11 WELLS NE 19 21:53: 2 101 Bel 1 .39 1.18 1.34 1.5 14.6 0.22 II STOVEPIPE WELLS HE 36.633 117.127, 0.4 0.10 0.6 161 DCI I .57 1.82 1.7 19 23:31:48 36.635 117.130 0.6 4.,' 13.6 6.12 15 MESQUITE FLAT 4.83 lot IOCI 1 .50 1.37 1.52 1.4 13.3 0.13 MESQUITE 20 2: 4:39, 37-.022 117.484 0.8 8.40 12 FLAT 2.3 165 aCi I .42 1.51 1.49 1.9 12.5 0.15 II USEHEBE.CRATER 20 22:25:13 37.018 117.488 0.6 7.03 2.6 157, OCI 1.09 4. 21 13:50: 7 37.451 115.591 0.4 I~r5 12.6 0.17 13 6.7 0.72 1.21 17.8 0.13 16 GROOMUBDEHEE CRATER,, 21 15:53:57 38.896 116.827 6.8 9.99 4.0 160 AC! RANGE NE 112 DCI 0.68 20.9 0.15 13 BCATTY 21 18:22:24 37.353 114.914 2.4 2.37 3.9 201 CDlII.30 1.26 1.13 22 1:31:12 38.821 117.135 1.2 13.5 0.41 11 DELAM•JR LAKE. 0.4' 2.74 1.4 109' ACI 2 .06 2.13 2.2 22 3:19:54 37.123 117.122 13.1 0.12 14 STOVEPIPEWELLS "8.3 4.15 4.2 98 DCI•I 05 1.25 8.94 17.5 0.09 -, 14 DONNIE CLAIRE SE 23 1:41:49 36.780 115.938 1.0 8.60 1.8 220' DOI 1. ,11 0.29 0.8 23 6:22:43 36.871 11.2 0.16 12 FRENCGHAN FLAT 116,219 1.1 3.89 2.5 113 881 0. '97 eP.68 4.9 23 11:51: 2 35.882 116.818 1.2 0.24 13 SKULL MTN 7.7C0.01 6.8 268 B00 I,. 54' 1.46 1 .44 10.2 0.68 11 WINGATE 24 11:59:39 37.226 117.346 0.6 1.6 ABD 1.to WASH 93 1.1 .65 1.4 11.9 0.14 12 GOLD LMOUTAIN 24 12:35:19 37.090 115.241 1.9 7.96 1.8 271 801 I 49 24 12:58:52 37.099 1.61 1 .41 1.8 9.9 0.17 10 LOWER PAHRANAGAT LAKE SW 115.243 1.9 6.80 1.8 261 0!' I. 78 .70 1.0 11.65 1 9.2 0.17 10 LOWER PA,,RANAGAT LAKE SW 24 14:14:48 18.027 115.135 2.3 7.89 3.9 3 19 80! I. 87 1.51 25 0:23:54 56.624 115.653 1.1 2.1 17.1 0.13 86*eSouthern Great Basin-. 0.61 1.6 153 OCI 2. 02 2.10 1.97 2.8 16.1 0.14 25 3:37:45 36.818 116.015 0.5 4.76 2.6 12 INDIAN SPRINGS 26 162 SO I1. 64 a .82 12.9 0.11 12 CANE SPRING 14:20:10 68.545 116.326 6.4 6.08 3.4 122 DCI 1.18 27 2:56:32 1.22 1 .03 1.5 21.5 0.11 12 SKELETON HILLS 17.272 114.956 2.8 8.22 3.3 238 CO! I. 37 .32 27 7:30:7 .58.721 1 1.7 17.2 0.16 7 DELAJAAR LAKE 115.887 0.4 4.94 1. 41 , Il 1.3 147 ACi 1.13 I .34 1.7 7.4 0.11 14 MERCURY 26 16:32:50 316.964 118.655 0.6 15.45 170 AC I. 30 1.81 0 .85 16.4 0.12 12 BEATTY 29 3:10:43 36.542 116.319 6.3 2.76 1.91.8 110 MTN ACI I. 41 1.71 1.29 1.6 21.3 0.09 19 SKELETON HILLS \ I ?'2 EARTHQUAKES 1991 LOCAL HYPOICETER SUMMARY. - SGB -3 DEL- RMS STAND 00o -RES. PH.#H U.S.G.S.1 ,- SYANO 12S MAGNITUDE ESTIUATES MIN , QUADRANGLE ERROR ERROR CAP Nd ULh ULv ULc' (KU) (SEC) LONGITUDE DEPTH z(KM) ( - Uca, LATITUDE W) H(KU) (KU) DEC) DATE - TIME (DEG. 9.2 0.07 16 BEATTY UTH (UTC) (DEG. N) A,1 1.10 1.38 0.64 0.4 5.63 182 13.1 6.66 9 BEATTY MTH 116.652 0.5 ADl 1.06 1.65 6.46 NIH 1.6 2.41 1.2 322 0.74 15.7 0.17 16 BEATTY JUL 29 13:38:31 36.877 116.737 175 DO1 1.15 e.86 6.87,17 CARRARA CANYON 1.3 22.21 2.1 1.52 6.98 13.6 29 19:14:41 36.875 116.660 163 ACt 1.19 0.86611 WESTOF GOLD MTNH 38.950 0.3 - 5.89 1.3 0.97 1.11 17.5 AUG 1 15:,8:51 116.736 1.9 115 ACI 1.11 0.11 15 BEATTY 18:38:33 36.874 6.2 5.14 SCI 1.14 1.08 6.64 17.4 1 117.462 - 3.6 146 0: 37.193 6.5 8.93 2 6:22 116.752 23.0 6.16 1 BLACK HILLS SW 20:49:10 '36.917 13C11.37 1.33 1.52 "2 12.42 3.3 149 33.0 6.26 8 WAUCOBA SPRING 115.415 1.1 CO1 1.35 1.14 1.49 DAIGRANT CAN'ON 2.4 8.1 268 1.27 A. -68.8,0.18 10 3 11:56: 9 36.530 117.940 18.68 BAl 1.45 STRIPED HILLS 37.851 1.6 12.41 1.6 96 6.56 * 5.5 6.87,12 "-3 18:48: 4 A117. e13 162 ACl 6.96 18.1 8.09 13 WEST OF GOLD MTH 1:33:55 -36.429 6o:4 7.64 0.5 1.36 1.31 1. 5 ,4 118.320 2.0 117 ACI 1.24 6 19.1 6.16,12 WEST,OF GOLD MNH -- 4 15: 8:41 36.692 117.405 0.3 6:16 DCI 1.76 1.49 2. 6.4 6.75 2.1 121 MTH - 5 7:7: 3 37.188 117.414 18.9 6004'8 WEST or COLD 2 2 1 2 1.27 5 M11: : 37.183 "121 ACI 1.22 -1.25 oF COLD UTH 0.3 5.74 2.0 1.18 18.7 6.06 16 WEST 117.410 126 ACI 1.21 1.34 8 WEST oF COLD MN. 5 11:36:18 37.181 0.3 ,9.21 1.6 .6.97 1.06 .18.66.15 117.407 2.5 121 e81 1.16 18.6,0.18 16 WEST OF GOLD NIH 5 -11:36:40 37.182 0.8 11.86 1.46 1.31 MTH 117.483 '11.22 2.5 119 "081 '1.26 18.8 0.13 16 WEST OF GOLD 5 .11:37:,2 '37.188 117.048 ,0.8 AC| 1.64 1:66 6.77 NIH 126 .4 19.2 6.17 43 WEST OF GOLD I'' , 11:37:44 37.154 0.5 9.29 2.0 3.05 2 5 ,117.412 1.6 107 'DCI 2.43 -5 -11:39:38 37.185 117.411 6.3 6.41 5 11:40:20 ,37.188 AB, 1.16 1.35 ' 1.19 19.1.6.13' MWEST OF GOLD MNH 6.5 1.i95 1.6 122 18.3 0.22 9 GROOM MINE SW 117.413 CCA 0.92 7 SYLVANIA MOUNTAINS 37.181 .1.5 4.20o 133 6.75 1;804 13.7-,.62 5 11:44:43 115.978 16.4 245 A)I 0.99 .6 13.1 0.68 11MGOLD MOUNTAIN 5 17:25:59 37.315 ,117.640 6.2 .ABI1.12"' 1.01 1.17 1 16.19 ,0.9 95 26.9 0.17- 13 BEATTY 1'7 •14:29:14 ,37.392 117.334 0.3 123 Be! 1.33 *0.81 16 RANGE Sw 37.200 6.8 15.50 3.2 '6.98 .2 9.6 0.13 SPECTER 9 2:25:17 36.899 116.825 AB1 1.16 9 •9:i71:1 0.4 9.06 6.9 ,1e9 SPRINGS '11 ,2:16:51 ;36.519 *116.149 .9 15.9 6.26 14 INDIAN 01 1.74 1.52 1.61 1 LAKE SE 1.6 0.69 1.0 186 68 24.6 0.18 14 PAPOOSE 115.7ý2 DOI 1.14 0.95 1 •7 •, 6.7.0.15 11 LOWER PAHMANACAT LAKE SW 13:13:54 36.569 1.1 -4.83 0.9 23e i1.30 11 S115.784 239 B01O1.46 :1.36 615.3,0.69 , 5 HOOVER DAM ' -37.e98 1.1 4'.62 '1;i 1.56 ,1.97 . LAKE SW .12 11:4a:40 115.223 2.6 288 OI 1.91 .7 7.4 0.21 12 LOWER PAHRANAGAT 22:13:31. 37.116 1.5 7.06 ,1.76 1.41 'I ;-12' 114.727 ; 2.33 2.2 '801'1.69 * 5.8 6.11 11 TIPPIPAH SPRING :15" 4:11:30 .36.058 '1.4 +I"J ACI'.86 0.53, S115.239 6.6 1.58 1.3 163 15 22:49:41:ý 37.117 116.172 12.2 6.16 11 SILENT BUTTE is8, 1:38:14• 37.011 8.91 1.6 ",0I 1.18 1.48 21.6 0.14 14 HANCOCK SUMMIT 220 1.33 1.25 1.6 '116.442 130 DCI 1.34 0.17 7 ALAMO 17:52:20 37.295 0.4 7.06 3.1 1.71 1.42 1.6, 13.9 16 115.316 2.9 "181 B0I 1.38 7.8 6.69 16 CARRARA CANYON 17.' 0:12:13 37.490 _115.212 2.2 10.93 DCI 1;15 1.12 -0.98 6.6 1.50 2.5 "143 34.5 6.15 9 DEAD HORSE RIDGE :-16s 11:36:41 37.292 -'116.670 DCI'1.81 1.26 1.73 OF GOLD MN .36.857 0.9 S.29 1.5 1132 6.77 18.8 6.69 12 WEST g19 4:36: 2 ,o115.352 1.3 'ACI 6:59 6.79 e.3 - .77 105 19• 5:24: 1 36.776 } 117:410 18.9 0.80 12 WEST OF GOLD MTN 9:42 37.183 19 11: 165 ACI! 1.27 1.37- 1.46 6.05 8 DELAMAR LAKE 0.3 8.51 1.6 1.45 1.26 1.2 13.0 3.6 197 SD1 1.31 / 22.2 6.06 16 TRIANGLE MATH 19 11:13:20 37.183 o114.989 11.0 4.28 ACI 1.12 .. . .1.17' 6.4 1.63 1.7 123 1.9g 31.7 6.69 8 WAUCOBA SPRING 21,% 5:11:15 37.300 -116.532 1.24' 1.52 3.5 -297 901 1.531'" 1.1 4.5 6.17 9 LAST CHANCE ATH 2 1 ),8:42:30 37.529 "117.944 1.5 13.34 ,: CI 1.33 1.31 1.34 6.9 1.02 -,3.3 -160 2.5 66.3 0.28 23 .*9REGIOHAL*** 21 13:10:40 37.075 117.687 221 501 2.67 2.46 21 18:34:58 37.256 114.467 1.1 5.18 1.3 6.65 16 HOOVER DAM 21 18:37:17 36.448 AD! 1.73 1.27 1.60 15.9 0.5 1.69 1.3 188 14.5 0.15 12 BOULDER BEACH .;v'" 114.733 156 B90 1.76 1.3, 1.50 22 5:33:16 36.064 114.754 1.7 e.41 1.6 22 11:40:19 36.052 - *1 r V.t.. ****. .** - .*. - :';Th. -'. .4 dl 1991 LOCAL HYPOCENTER SLL&ARY - SG. EARTHQUAKES STAND' STAND AZI OO0 DILDEL-, RES.• IN DATE - TIME LATITUDE LONGITUDE ERROR DEPTH ERROR GAP 12S M&GNITUDE ESTIMATES P1. U.S.G.S. (UTC) (OEG. N), (DEG. W)' H(KM)' (Kw) Z(KW) (DEG) Mco Md MLh MLv MiLc (KM) (SEC) QUADRANGLE AUG 22 15:39:14"37.202 114.883 1.7 0.84 1.5 246' E")I 1 .47 1.23 1.32 2.1 27.2 0.13 9 DELAMAR 3 NW 22,,20:24:22 37.261 117.715 1.2 0.15 1.4 186 ADI601 1.38 1.52 1.58 1.2 6.9 0.21 12 LAST CHANCE 1TH 22 ,21:38:34 37.805" 118'.211 0.4 2.36 0.6 191 8.911 04.59 138- AC1 A.351 3.9 0.05 10 TIPPIPAN SPRING 23,,14:48:17 37.7608 118.365 0.5 8.51 8.5, 1.80 1.47 1.7 2.4 0.10 10 GEORGES WELL' *1. 23 15:31:10 37.812 114.691 1.3 3.25s 267 COI 1.43" 1.67 1.29 23.2 0.13 8 THE BLUFFS 23 :19:17:37 35:893. 1153.002 2.7 8.50 2.6' 211 COl 1.45 ,22.5 0.13 11 SLOAN NE 23 19:55:29 37.241 114.968 1.3 4.51' 7.2 221- CCI 1.57. 1.37. 19.8 0.14 9 DEL.MAR 3 NW 23 -19:57:49 ,37.251 114.984 1.1 8.34 2.5 214 DOI 1.27 1.16 1.19 1.4 18.3 0.15 '91 1.13 1.61,, 1.7 DELAMAR LAKE 23 20:13:22 37.260 115.014 1.6- 8.02 2.7' 264, BDII.61, 18.6 6.16 8 ALAMO SE 23 20:41:29 '37.244 114.978 3.8 3.87. 2206 C01:1.29 1.46 1.12- 1.5 19.5 6.16 8 DELAMAR 3,1W 23 ,21: 5:57, 37.231 114.926 3.6 0.35: 2.6 231 C0I,1.55 1.37 1.9 22.4 0.44 9 DELMAAR 3 NWI 24 8:26:10,37.106 117.084. 0.5 7.46 2.1 98 96011.38 1.28 1.21 1.4 14.4 0.17,19 DOWI4E CLAIRE SE 115.0647 24 19:18:26 35.831 5.6 6.01. 219 001 1.32 28.2 6.81 6 SLOAN SE 25 1:52: 3, 35.812 115.025 1.6 5.67 2.4 249 B9I 27.3 6.04 5 SLOAN SE 25 2:39: 8 36.867 118.746 0.4 7.76 1.9 169 ABI 1.06 0.45' 13.2 0.11 17 CARARA CANYON 25 , 3:15:59 36.617 116.241 0.3 7.39 0.8 142 ACI 1.19 0.68 1.3 9.3 6.09 16 SPECTER RANGE SW 25' 14:32:26, 37.762 116.365 0.4 8.60' 0.7 103 AD! 2.12 1.67 1.631, 2.6 6.14 20 GEORGES WELL 28 5:33:22 35.950, 116.891 0.8 6.09 2.4 2"8 901 1.34 1.42 1.44, 1.5 16.0 6.08,. 6CONFIDDCE HILLS 26 13:28:37 37.552 118.472 1.3 0.330 317 DOU 1.83 2.03 2.1 51.9 0.16 8o.REGIONAL...6 ' 27 9:38:33, 27 15:42: 8, 36.70237.885, 114.717 1.7 3.26# 259 COI 1.15 1.32 22.2 0.24 11 THE BLUFFS 116.285 e.8, 7.47 0.7 203 ADI 3.6/ 4.7 6.08 10 STRIPED HILLS 'I - 28 9:16:20 37.512 117.231 0.7 12.94 1.9 148 ACI 1.23 1.27 1.38 23.5 6.10610 RALSTON 28 16:12:52, 37.181 115.087 2.2 10.60 2.5 254 D01 1.66 1.41 6.85 1.5 9.60.14' 6 LOWER PAHRIAAGAT' LAKE 28 20:55:21, 37.440 115:497' 0.6 0.68 6.9 143 ACII1.32 1.50 1.3, 2.0 22.860.1512 CRESCENT RESERVOIR A' 29 2: 8:51 37.512 117'221' 1.6' 18:73 4.9 147 OCI 0.99 0.96 1.09 23.7 0:15' 7-RALSTON' 29 17:26:33- 37.326, 115.019, 1.0 6.81 1.3 182 001 1.62 1.35 1.7 9.4 6.07 9 ALAMO SE 29, 19:24:27 37.2668 117.577 0.4 10.34, 0.5 94 A)I 1.02 1.65 1.00 7.2 0.07 I1 TULE CANYON 29 21:34:23. 37,460, 115.617 1:2 14.58 2.5 128 981 1.52 1.26 1.41, 15.3,6.15. 8 GROOM RANGE NE.' 29 21:37:42, 36.920 1160865 0.9 16.78 2.4 128 . 081 .*52 16.6,0.17 12 BEATTY' 30, 6:37:37- 37.260 115.201 1.6 12.77 2.2 134 DOI 1.32 1.18 1.14 1.6 10.2 0.16 9 ALAMO. 30 11:31: 8 36.653 117.757 4.1 0.13 3.2 276 CCI 1.73 1.61 1.78 35.7 8.20 12 NEW YORK BUTTE 30 11:31:,8 36.642 117.771 3.2 2.29 10.5 277 COI 1.73 1.42 1.60 37.3 0.17 13 NEW YORK(BUTTE 36 20:41:55 37.258 115.209 0.8 10.99 1.9 128 ABI 1.44 1.13 1.19 1.6 11.1 0.12 9 ALAMO 31 9:10:22 36.388 118.901 0.7 12.79 1.7 135 ABI 1.16 1.51 1.27 17.9 6.12 11 WEST OF FURNACE CREEK SEP 1 5:50:59 36.840 115.990 0.8 6.13 1.6 167 DCI 1.15 0.68 11.6 0.15 11 FRDENCHAN FLAT 2 14:30:33 36.405 116.987 6.4 8.86 0.7 95 ABI 1.62 1.34 1.05 1.3 10.3 0.66 10 WEST, OF rlMNACE CREEK 4 22:29:48 36.619 117.129 0.4 5.18 2.1 1" OCI 1.84 1.84 2.1 13.7 6.08 14 STOVEPIPE WELLS 4 23:12:53 36.623 117.132 0.2 4.36 2.1 166 !CI 1.42 1.56 1.54 1.4 13.3 6.05 12 STOVEPIPE WELLS 5 11:12:43 37.373 114.907 0.6 2.31 1.1 197 ADI 2.12 2.2 13.2 6.07, 8 DELAAR LAKE 5 15:58: 4 36.823 117.1 3 0.8 0.57 2.0 109 ABI 1.83 1.69 1.9 13.0 6 6.11 13 STOVEPIPE WELLS 3:41: 5 36.631 116.324 0.3 3.36 8'.2 299 ADI 1.14 0.99 2.2 0.04 6 13:49:22 11 STRIPED HILLS 37.334 115.031 2.8 4.74 5.8 170 CCI 1.28 1.21 1.1 8.2 0.19 8 ALAMO SE 6 14:47:39 37.308 117.523 6.8 6.77 2.4 9S C1I1.25 1.30 1.15 1.6 13.8 0.17 10 TULE CANYON -6 14:51:14. 37.310 117.522. 0.4 5.71 1.4 75 ACI 0.99 1.00 14.0 0.09 11 TULE CANYON I I ( 0 'I - 0 L S I 4 4*W .1. . I 4•" *1 ' , '- - •"'/' , 1991 LOCAl L HYPOC ENTER SLuiLAY -SOSc ARTIOJAXES 000'' DEL- RU IN ''' STJ STAND AZI MR DEPTH ERROR GAP, 125 MAGNITUDE ESTIMATES MIN,, RES. PH. U.S.G.S..-, DATE - TIME 2. LATITUDE LONGITUDER1 01) (u )' Z(KM) (DEC) , Uca' Md MLh, MLv,'ML¢ ' (KoM)(SEC), , GCUADRANGLE (UTC) .. ' (DEC. N) (DEC.'W) H( SEP i ý 1:19:21" 37.924 116.132• 0, .4, 2:76' 2.8a 120 DCI 1.50, 1.64 1.57, . 24.9 0.14 14 REVEILLE PEAK-NW 6.65 36.623' 117.135 0 .2$ 5.95' 1.3 108 ACI 1.67• 0.881 0.90 . 13.1 12 STOVEPIPE WELLS 6 19:22:31L ABIS I135 1.59 CANYON .+ 6' 19:26:23 37.3066 117.523 0..3 7.39' 0.9; 78 1.32, 1.5' 13.6 0.08 13 TULE 5. 19:41:35 '37.309 117.522' 0:.4 7.28' 1.4, 84 '60.855 0.79 6.61 . 13.9 0.10 11 TULE CANYON .5, 9.52, 0.6 145, ACI 1.26, 6.36 6.69 2.9 0.16 12 IJERCURY-- . 6, 22:39: 5 36.635' 115.966 06 1.11, 6 23: 0:506 37.814* 117.747 1,.8 0.89, 1.3, 267, BOI' 1.285, 1.23, . 12.1 6.14 11 SILVER PEAK , 3:56, 37.-118 117.226 o0o '.9 4.16'' 11.2 94, CCI' 1.47, 1.521 1. 5 17.0 0.27 13 BONNIE CLAIRE SW S3:' 9.8 6.12 12 UOIEHCE CRATER 7 22:18:60;'37.084 117.375 0 .5 0.99' 6.8 1191 AB! 1.26 1.14, 1• 2: .4 1.72' 1.21 159 AC!' 1.10 1.38, 6.87. 13.3 6.08 14 BEATTY NiTN 8 , 3:45:19 36.880 116.734' 0 .9' 1 1.21" 3.4 258 SDI 2.16 2.02 2.23 + I. 9 22.7 0.20 11 THE BLUFFS .• 8 12:55:26 37.816 114.724' .1• 5:16. 8 17:27:23" 36.859 114.491' 1 1.3 208 B0D'2.43 3.ee 2.53, 2. 4 t76.9 0.22 23 *.soREGIONALe.s .4 9' 5:39:26- 37.226' 117.673 0 .1- 12.35' 0:2 165 ACI 1.27 1.43 1.39. 1.7 2.8 6.03 13 HANGING ROCK CANYON 9! .9 2:45o 281 CI: 1.81 6.90 1.406 35.4 6.23 S8 DARWIN- ,, 9, 1'657: 0' 36.467' 117.6051 4 .9 1:11:585 37.735' 116.062 0 .8 2.02 1.4 141 9CIl, 1.81 1.72 1.68 2. 1 5.7 6.18 13 MOIOTONY VALLEY 18' 16:51:17 37.386, 117.136' 0 .3' 1.28 0"6 285 ADI' 1.00, 6.80 0.96 14.4 0.04 9 STONEWALL PASS,, 10o 13:36:37, 37.758 115.418: 0 .5' 4.26 4.5 98. DCI' 1.55' 1.56 1.45 1'.7 14.5 0.13 11 MURPHY CAP%,-f 37.20C' 116.529, 0 .4' 0.83 0:6 128 AC!+ 1.63 1.81, 1'39 1. 6 13.7,6;12 14 THIRSTY CANYON 10 17:45:36' HTN 11" 5:27:53 37.506' 114.629 0 .7 5.35' 2.1 274 8Ol1 1.56 1.22 1.40 14.6 0.65 8 CHCKECHERRY 11 ' 7:45:58 37.885' 114.691' 1 .3Ž 5.e09 8:2 266 CDI 1;51 1:261 1.492 22.5 6.12 - 8-THE BLUFFS--, 6.96 1.3 13.16 115 CANE SPRING -' 11 8:45:10• 36.814% 116.025! e .4' 4.95 1.9 138; ACI1:11 4, A 11' 9:6e:7 36.815' 116.026" 0 .31 3239' 5.1, 141' CCI: 1.03 6.89, S13.1 6.67 12 CANE SPRING -, 9o0: 1.52, 1.28 1.56, 1.7 14.5 6.11 10 CHOECHERRY M1TN 11 10:19:53' 37.511' 114.626. 1'1' 7:64 2.0 276, :9" 11, 16:23:25" 36.988 116.203, 0 .4 6.54" 0.7 148, AC! 8.83 6.15' 6.660.11 1 MINE MTNtD 11• 26:43: 2 37;213' 1152626 0 .8, 2.48 5; 9 134 CCI' 1.59 2.12 1.69,1 2. 6, 19.0 0.17 16 FALLOUTHILLS NE 11 23:58: 9' 37.036 116.299' e .4' 6.87' 0.7' 97 AS! 1.17 1.66 1.:1, 1. 4 6.2 0.12416 BUCKBOARD MESA 12, 13:16:11 36.677' 116:264 0 .6 4.40 0.7ý 248 ADI 1.65 2.30 1.48 1. 2, 7.3 6.08 16 STRIPED HILLS 12 16:.8:51 37.851 116150' 0e.2 0497 0.3 151 AC! 1.24 6.72 1.11 S21.1 0.02v 6 REVEILLE PEAK 13 1:54:27, 36.861' 117.720' 1 .I1 5.59 8.6 236 CDI, 1.51 1.18 1.64- 1. 8 28.8 6.16 14 WEST.OF TEAKETTLE JUNCTION 13 20:31:59' 37.522ý 115.382' 0 .6 1.00 1.e 178 ACI 1.13' 0.57 19.6,6.68 7 CRESCENT SPRING 14 11: 3:49. 36;237' 115,425, 1,.2 18.80' 1.5 294 9011,1.46 1.13 1.30 I. 3 17.3 0.15 14 LA MADRE MTH 14' 11131:'4f 36.8565 116.194' 0 .9 0.15 0.6 114 Sol 1.11 0.55 6.7 2.368.21,13 SKULL MITN 15. 2:50:58' 37.001' 116;370' 3.'9 0.97. 211 CDA, 8.91 13.2 6.17 5'BUCKBOARO MESA 15 3:44:26 37.232 1165491, 1,.9 3.84. 225, CDA 1.68 31.7,0.20 9 SCAUCHAM PEAK 15 5: 1:44' 37.351' 116:423 2 .9 7.6e0 324 COA 1.33 38.9,6.16 8 SILENT BUTTE 15, 6:49:57' 37.196 118.471' 6 .4 7.e0. 301, DOA 8.75 27.8 6.26 7.SCRUCHAM PEAK 15' 7: 1:13" 37.145' 116.397' 3 .7 10.44 6.6 288 COA 1.06 19.1..11 6 SCRUCHAM PEAK' 15 ý8 1: 7 37.245 116.437, 1 .1'% 1.00 2.3 218 BOA .. 1.16 29.5 6.12 11 SCRXHAU PEAK 6.88. 35.6 6.16 6 SILENT BUTTE 15 8: 4:52 37.287 - 116.481 1 .4 3.60. 316 CDA 11: 2: 4 36.856 116.004 9 .4 2.87* 333 DOA 8.34" 14.7 6.51 7 CANE SPRING 15 SCRUCHAM 15 15:23:48 37.220 116.409 le.4 .-0.53. 348 DOA 6.79 20.6 6.10 7 PEAK 15 15:39:50 37.320 115.395 1 .3 ,-.16.82 4.1 322 BOA 1.09 34.7 6.63 6 SILENT BUTTE 3.41 V' 15 18:37:37 36.731 116.282 0 .7 0.7 172 9CI 1.00 1.25 6.71 0. 8 1.6 0.16 16 STRIPED HILLS -1 -fl 16 5:35:43 37.284 116.e52 6 .7 2.39 2.3 93 8!I 1.18 0.87 1.07 I. 5 9.9 6.15 10 OAK SPRING BUTTE 5 a18:25:54,36.474 117.016 0.8 12.44 1.4 89 S•1 1.34 1.45 1. 4 11.8 6.20 15 EMIGRANT CANYON F -y . q) / .9 1 'I i - -, - -, I , 1991 LOCAL HYPOCEHTER SLJ.&ARY - SGO EARTHNUAES STAND AZI 000 DEL-' RMS IN STAND 'RES. PH. U.S.G.S. ERROR DEPTH ERROR 12S •AGNITUDE ESTIMATES WIN" DATE - TIME LATITUDE LONGITUDE (DEG) Ico . Md lLh ULv ULc (KM) (SEC) . QUAAORJ4dLE (UTC) (DEG. N) (DEG. W) H(KM) (KM) 1.a 241 7.9 6.12 10 LATHROP WELLS 36.656 116.428 1.0 5.42 801 1.12 0.94 EP 17 7:47:58 0.7 205 ADI 1.09 1.26 0.59 5.7 6.67 15 STRIPED HILLS 17 13:39:52 36.693 116.289 0.4 3.62 1.6 2.15 1.1 199 ADl 1.48 1.38 1.47 16.1 0.69 10 DELAMAR "' 17 14:13:19 37.487 114.869 6.7 NW 0.5 7.H 2.3 107 ,qCI 6.57 0.48 18.6o.6, 8 BONNIE CLAIRE 19 6:24:58 37.160 117.157 279 ADA 0.24 5.6 0.68 16 SPECTER RANGE W -19 5: 118.226 6.7 6.61 0.7 1:31 36.714 0.9 234 BOA 6.59 17.760.17* kUIIN MTH '19 7:35:24 36.889 116.158 6.8 0.27 SW 1.1 9.42 1.8 172 DOI 0.95 0.98 1.62 11.4 6.11, a MONTEZUMA PEAK 19 20:41: 4 37.601 117.416 23.1'0.27-'6 AMMNIA TANKS 14.6 2.91. 352 DOA 6.83 19 23: 7: 4 37.242 116.367 258 1.26 1.04 23.6 6.16 10 WILLO PEAK 4115.843 6.9 7.10 2.4 801 20 23:23:31 35.459 2.1 226 801 1.37 1.15 1.38 2.6 .2.2 0.28"11 CHOCOLATE MOUNTAIN 21 7:32:11 37.405 117.966 2.2 9. 68 I.IS1 1.3 7.54 1.4 178 DCI 1.31 1.37 p1.5 3.4 6.16,11 CHOCOLATE MUTAIN 21 7:35:54 37.485 117.876 6.9 ACI 1.18 .47 ,1.4 "2.9 ,.12 11-CHOCOLATE MOUNTAIH 21 -7:49:,2 37.418 117.881 ,8.9 7.32 159 6.9 9.01 0.9 2e7 ADl .1.40 1.52 .1.9 3.0 6.14 13 CHOCOLATE MOUHTAIN 8:33:48 37.400 117.895 !1. 0.14 11 ,CHOCOLATE MOU4TAIN 117.884 .1.1 9.22 162 acI 1.09 1.11 1.4 2.3 16: 7:56 37.416 12.4,0.13 IS SMRINGOALE SW 116.947 0.4 4.02 3.9 95 scI 1.53 1.56 1.8 15: 18: 24 37.869 1.26 7.6 6.15 17 GEORGES WATER 116.254 6.5 66.65 1.2 ,123 881,1.40 1.3 8:59:58 36.825 0.84 *6.92 13.6 6.16 '•9 D*1441ECLAIRE SE 37.105 117.629 6.5 8.99 1.4 102 ABI 1.11 15:56:31 .A•l 1.58 1.74 1.65 1.5 22.2,4.12 13 HANCOC.KSLMIT 20:29: 3 37.471 115.288 60.4 8.76 2.8 85 6.88 8.4 133 ACl 1.53 0.93 0.92 1.5 22.536.02 11 HANCOCK SU4IIT 22:19:25 37.461 115.295 .6.3 NE 7.60 8.9 200 CO1 1.34 1.22 A1.25 27.1 6.25 16 FALLOUT HILLS 9: 2:20 37.213 115.507 1.8 .1.66. NE 2.8 11.58 6.7 288 Col 1.68 1.62 28.1 0.24, 7 FALLOUT HILLS 9:7: 8 37.193 115.510 1.5 22.6 6.69 12 HANCOCK SUMMIT 115.295 6.3 5.34 .3.2 132 DCI 1.48 2.H4 •1.37 9:32:25 37.468 ).78 23.1 6.11 7 HANCOCK SUIJIT 37.469 115.306 .6.8 3.94o 133 CCI 9:43:41 102 DCI: '1.69 1.59 1.89 1.9 13.9 0.10 15 STOVEPIPE WELLS HE 14:49:19 38.630 117.124 6o.4 4.57 3.5 .1 8.4 132 ACI.1.16 1.87 o.94 22.6 8.03 •7 HANCOCK SLUMITX 24 19:55:22 ''37.468 115.295 0.2 0.00 ,0:5 1.94 3.4 132 DCI -1.15 1.36 1.63 22.9 0.15 12 HANCOCK SUMMIT' 25 2:58: 7 '37.468 115.298 1.4 ,5.9 6.16 9 EMIGRANT CANYON 117.044 6.8 11 68 1.6 91 AI 1.27 -1.12 25 - 3:43:34 -38.419 286 A0I ,1.68 6.99 0.35 9.9 6.12 11 RAINIER MESA 25, 7:46:0 37.126 116.238 6.9 6828 ,1.4 'CDI 1.85 ,1.54 3.9 ,2.88 10.7 ,273 1.65 1.9 23.7 0.18. 9 THE BLUFFS 25 9:33:18 37.810 114.663 1."6 1.54 S54.4 0.10- 6qjIMTAIN SPRINGS 25 11:16:29 36.115 115.550 3.7 8.41s 291 Col 1.50 0.3 6.93 6.4 146 ACI 1.67 1.5e 1.53 1.5 22.5 6.6" 12 H4CO0K,SUWWIT 25 21:10: 6 37.462 115.296 6.89 22.4 6.11 1e HANCOCK SUMMIT 115.295 6.4 3.01. 133 ,CCI 0.94 1.20 1.5 25 21:14:31 37.461 .801 1.86 1.97 1.77 1.7 8.1,6.15 12 LOWER PRAkiNA•AT LAKE SW 25 21:31:33 37.110 115.243 0.8 5.33 1.8 188 6.4 60.08 0.6 87 ACI ý2.03 1.85 1.9 22.7,0.12 13 HANCOCK S.LIMIT 25 21:46:48 37.466 115.296 1.1t 1.5 21.5 6.26 9 HANCOCK SUMMIT 115.278 1.1 9.53 4.4 125 DCI 1.18 0.89 25 21:57:12 37.485 191 DO1 1.62 1.58 1.6 22.6 6.16 6 HANCOCK SU.64IIT 25 22: 4:22 37.460 115.290 1.9 17.60 3.4 0.4 6.51 0.5 ,,133 ACI 1.93 1.79 1.75 2.1 22.3 0.1 11 HANCOCK SUMIT 22:22:31 37.462 115.293 7.4 6.16 14 LOWER PAHRANAGAT LAKE SW 37.114 115.234 6.4 6.53 ,e.9 136 A•l 2.21 2.15 2.67 2.1 23:15:36 1.31 1.68 1.19 1.4 "22.2 6.14 13 HANCOCK SUMMIT 23:44:24 37.465 115.291 0.5 7.67 2.6 87 DCI 0.9 2.18 2.4 135 DCI 2.28 2.24 2.2 7.0 0.19 13 LOWER PAHRANAGAT LAKE SW 0:34:22 37.119 115.236 0.14 11 LOWER PAHRIAAGAT LAKE SW 115.239 6.9 5.17' 1.7 191 AOl 1.90 1.78 1.68 1.2 7.8 1:43:54 37.112 6.85 1.5 22.7 6.68 9 HANCOCK SULAIT 1:47:57 37.474 115.2;3 3.4 3.14. 130 CCI 1.24 1.22 115.2381 2.1 5.69 2.1 271 001 1.52 1.34 1.43 1.4 9.4 6.15 9 LOWER PAHRANAGAT LAKE SW 26- 1:53:31 37.e94 1.74 1.69 1.6 22.4 0.14 15 HANCOCK SUMMIT 26 -2:23:36 37.462 115.294-....0.3 12.00 1.7 88 ABI 1.60 Ii.- I C)ii 0 jj199 LOCAL kYPOCENTER SUMIAARY - S08 EARTHQUAKES AZl 000 DEL- RMS IN SSTAND STAND UIN -RES. PH. U.S.G.S. ERROR ERROR. GAP 12S UAGNITUDE ESTIMATES /I LONG ITUOE DEPTH DATE -TRUE' L'AT'ITUDE Uca Md MLh ULv 1ILc (KM),(SEC) ,QUADRANGLE (UTC) (DEC. N) (DEG. W) H(KO) (KM) 'Z(KW) "(DEG) :•e6.6 4.68. 16 HANCOCK SUARIT - 88 OCI 8.93 0.686 0.94 "i22.8 6.15 SEPý 2 6">2:57:50 :37.465 I115.298 1.8 7.5 6.12 11 LOWER PAHRANAGAT LAKE SW .1.2 ' 188 ADIA1.95 1.94'' 1.92 268-' 6:4e:34 37.115 115.240 .0.8 6.45 RAINIER MESA 7:89 189 ADI 1.32 1.97'*1.36 1.3 010.3 6.11, 15 "26 7:49:56 37.136 115.224 0.7 1.1 RAINIER MESA 6.9 7.82 1.5 184 AD[ 1.14 1.28 0.59 1.3 19.3 0.14 13 26 7:52:36,37,136 116. 235 1•.68• 0:99' "16.6 0.14 14 RAINIER MESA 6.7 7.59 1.3 187 'ADI 1.16 1.4 ,,26 ' 9:44: 5 37.128 116.227 1.16 1.01 1.5 ,23.0 0.16 12 HANCOCK SUMIIT S26 11:24: 6 37.472 115.299 _,9.5 0.93 "6.9 86 9CR 1.11 '6.93 22.4 e.e8 9 HOC= SL4J.I T 9 6.6 131 'ACI 1.62 1.07 -26 12:19: 37.470 ,115.291 6.4 6.90 "0.80 1.5 22.5 6.15i12 HANCOCK SUMMIT :,26 '13:17:47 '37.473 115.292 6.5 7.06 3.6 85 oCi 1.19 0.93 1. 58, 1.33 1.6 15.5 6.20 10 OAK SPRING BUTTE 116.622 6.5 3.640 - 146 CCI 1.33 26 '14:37: 6 37.389 1.19 1.5 4.5 6.13 16 YUCCA LAKE 116.068 6.5 6.7 149 ACI 1.25 26 15:45:26 \36.889 10.96 1.34 1.25 - 35.2 0.13 8 HANCOCK SUIAMIT .26 -19:14:24,,37.478 j 115.274 _6.6 3.68. - 95' CCI 2.26 CCI 1.29 1.24 0.90 1.5- 22.5 0.13 11 HANCOCK SURI T 226 22:51:2237.466 115.294 .0.6 3.110 - 144 '85 9CI 1.21 1.39 '1.14 22.5 0.15 12 KANCOCK SULSIT 26.3:15:35 ý'37 476 115.290 6.5 7.0e 3.8 0.10 9 HACC SUMMJIT 6.5 7.6e "3.3 131 jBCI 1.13 '1.29 1.04 1.5,•22.7 26 '23:31:46 -37.474 115.296 6.63 6.7 0.11 13 STRIPED HILLS 116.272 e.7 8.78 0.7 210 ADI 1.09 26 23:51:26 36.682 1.14 1.60 22.6 6.68 8 HANCOCK SUMMIT 115.294 0.5 4.63 8.7 131 Cri 1.01 26 \23:54:49 37.476 1.56 1.25 '1.47 22.6 0.64 8 HANCOCK SUMRIT '-I 27, 8:21:16- 37.467 115.295 0.2 7.0.64 .0.3 ,,132 ACl' 1.39 1.82 ' 1.41 1.4 22.3 0.12 11 HANCOCK StUMIT 27 8:41:54 37.473 115.288 6.5 7.24 ,3.1 ,129 OCR V.35 6.87 1.4 26.8 6.69 6 HANCOCK SUMMIT ;'115.270 1.4 1.62 4.0 .J96 001 1'15 0.99 'Ž27 • 0:44:37 37.475 1.13 1.12 - 22.2 6.11 8 HANC SUMMIT S27 8:46:58a 37.472 115.287 0.7 7.81 .3.8 129 9CI 1.02 2.8 87 9CR 1.61 1.79 1.50 1.5' 22.3 0.11 13 HANCOCK SUMMIT S27 1:25:58 37.463 115.292 0.4 6.56 HANCOCK 6.3 2.0 87. ACI, 1.71 1.52 1.9 22.0 0.09 13 SUMMIT '27 .3: 2:35-37.463 115.289 .7.43 1.5 SUMMIT 7.75 3.3-.•84, 9CI1..38 1.55 1.34 '22.3 0.14 11 HANCOCK 27'' 3: 9:15 37.478 115. 287 S0.6 2.3 ' 22.1 0.12 16 HANCOCK SUMMIT 27-, 3:15:15 37.463 115.290 0.4 .6.19 .3.9 ._87, OC1,2.55 2.55 "9.1 87a OCR 6.98 1.09 C'.73 1.5 22.3 0.16 11 HANCOCK SUMRT S27 3:19:44' 37.486 S:,115.291 6.6 4 .64 22.5 6.09 9 HANCOCK SUM.MIT 6.5:" 4.79 5.1 129 OCR 1.35 1.51 1.24 27 3:29:12, 37.475 115.290 1.4 21 4 6.18 10 HANCOCK SURI T I' 115.278 0.8 '-4.77 1.2 '127 0I11.63 1.70 .. 45 27 7:11:54- 37.472 1.47 0.92 1.5 20.9 0.19 9 HANCOCK SUMMIT 27 16:34:27 37.496 ,115.290 1.0 10.74 3.7 126 681 1.49 1.66 0.61 0.9 ' 3.6 0.11 14 SPECTER RANGE Ni ,,,116.242 0.6 - 5.34 0.5 , 202 ADI 6.97 27 11:45:26- 36.721 0.99 0.65 1.5 21.5 6.28 6 HANCOCK SUMMIT 28. 8:36:58 37.476 115. 278 3.8 7.6e. - 249 COI 1.04 HANCOCK SUMMIT 6.3 190 CC)011.12 0.82 0.66 • 20.7 0.21 9 28 :16124:38" 37.475 115.289 •,,1.4 .5.96 BONNIE SW 0.58 .85 6.9 t116 ACr''.e8 1.14 0.82 13.1 6.14 9 CLAIRE 28 13:13:15' 37.063 .117.143 CROCU RANGE NE 115.554 1.1 11.81 4.4 126 9•811'.13 1.0 1.0e 1 20.2,6.18 8 28 17:30:27 37.440 1.5 22.6 6.10 11 HANCOCK SUIMMIT 28 18:18:15, 37.465 115.295 , 6.3 0.49 00.8 132, ACI 1.24 1.18 0.87 6.38 9.6 113 ABI 1.30 "1.32 1.2- 5.3 6.16 14 GOLD POINT' 29, 8:30:25. 37.284 ,,,,117.313 0.4 6.09 T•IRSTY CANYON W S29, 11t :8:e•37.165 ,,116.,689 0.3 7.47 9.5 ,139, AC| 1.26 1.28 6.97 "-3.8 15 6e.6 '2.96 1.5 22.4 0.18 13 HANCOCK SUIMMIT 115.292 3.7-, 129' 9CI 1.23 1.43' 1.02 29,.11:33:53,,37.476 1.46 1.68 1.5 21.969.16 9 HANCOCK SUIART, 29, 17: 7:45'-37.481 115.266 6.9 _,,7.6e 5.1 '127 OCI '1.18 '1.36 3.4ý 276 901 2.18 2.07 1.89 1.5 9.3 0.15 9 LONER PAHUANAGAT LAKE SW 29 17:37:41 37.089 115.221 2.2 8 LOWER PAHRANAGAT LAKE IM 1.5., -11.69 6.4 266 CDI 1.37 1.38 1.31 32.2 6.20 29 22:48:38 37.139 115.188 HANCOCK SUMRIT 115.368 -0.8 1.07 3.3 135 1 DCI 1.13 ',"1.28 1.10 1.5*'23.660.09 7 29 23:26:56 37.463 '-1.21 0.89 1.5'1 22.5 0.141 OHANCOCK SUMMIT 29 23:34: 9 '37.470 115.292 6.6 4.27 11.0" 86as"CC! 1.24 1.8 7.7 6.10 11 LONER PAHRNACAT LAKE SW 115.227 6.5, 4.76 1.2,4 191 ADl 1.66 1.70 1.40 30 8: 7:47 37.107 6.67, 8.5 0.22 11 SKULL MTH OCT 1 4: 7:55 36.783 116.138 2.6 6.82 2.3 287 BOA . £ .. I i''' 1991 LOCAL HYPOCENTER SIUJARY - SG8 EARTHQUAXES I . , . . 11 DEL- RMS IN STAND STAND AZI OD MIN RES. PH. U.S.G.S. LONGITUDE ERROR DEPTH ERROR GAP 12S, MAGNITUDE ESTIMATES DATE - TIME LATITUDE (KM) QUADRANGLE (UTC) (DEG: N) (DEG. W) H(KI,) (KW) Z(W) (DEG) ucca 'M ULh ULv ULc (SEC) 11:56:39 37.010 116.869 1.1 8.69 1.7 188 BOA 0.81 15.1 6.08 16 SPRINGDALE OCT 1 PAHRANAGAT LAKE SW 3 3:43:30 37.101 115.213 6.9 0.49 1.6 164 CCI 2.19 2,13 2.17 2.4 7.9 0.31 33 LOWER A 115.665 16.8 4.00. 171 DCI 1.18 1.09 23.9,0.27 6 VALLEY 3 18: 5:36 36.330 DONNIE CLAIRE SE 4 1:49:11 37.114 117.064 0.3 8.48, 1.2 186, ABI 1.06 0.81 0.96 14.9 6.16 14 16.5 6.06 it SPRINGDALE -- :1' 4 19:48: 18637.016 116.855 - 0.3 1.66 0.9 116: ACI 1.15 6.82. 0.95 ý1.6 4 20:41:10 37.478 115.276)" 8.7 7.00 2.2 192 0D1 1.23 1.17 1.07 21.5 6.07 6 HANCOCK SIULUIT 4 22:26:22 36.986 "116.748 6.2 7.00 1.0 115 -ACI 1.22 0.96 17.9 0.04 13 BEATTY MTN 18.3,6.08 II WEST OFGOLD UTN 5 9:40:44 37.157 117.404 0.3 6.10 1.2 Ill ACI 1.28 1.37 1.21 11: 6:35 37.159' 117.399 0.4 7.80-- 1.5 125 ACI -1.088 0.75 6.96 18.3 6.08 9 WEST Of GOLD UTN 8 1:32:55 37.213 116.533 . 6.5 6.91 1.9 133 ABI 1.15 0.92 6.82 12.9 0.12 14 THIRSTY CANYON 8 12:43: 2 36.933 117.472 8.3 56.41C' 1.0 178' ACI 1.206 1.27 1.06 1.3 13.4 0.04 9 TIN MOUNTAIN S. UBH•BEE 8 14:47:46 37.063; 117.461 0.6. 2.59 1.4 160 'ACI 1.25 0.86 1.18, 1.3 16.2 6.14 It CRATER 9 6:22:21 37.194W 114.989 1.3 13.72 1.0 235 9OI'1.88 1.79 2.06 1.9 17.9 0.15 I DELAMAR 3 NO 6.6 SPECTER RANGE NO 10 5:14:47 '36.727 116.2901 ' 0.8 16.25 6.8 223 A/I 1.07 6.60 1.2 0.12 12 11 22:57:24 37.105 116.995 0.4 2.17 1.2 164-- ,A I 1.51 1.12 1.22 1.4 14.1 6.12 26 SPRINGDALE SW 12 4:40:22 37.438 115.576 1.6 10.89 5.2 142 CCI 1.09 1.36 1.29 19.7 0.17 8 CROOM RANGE HE 12 15:47: 6 ,35.962 116.995 1.0 4.38 3.1 260 9O1 1.36 l.66 1.07 1.3 11.5 0.89 7 WINGATE WASH. 15 FALL CANYON 13 4:33:60- 36.777 117.225 8.4 0.39 6.6 83 - ACI 1.68 1.74 1.74, 1.6 15.3 0.12 NE. 13 21:57:59 37.167 116.753 0.8 2.83 6.7 165 DCI 1.64 1.84 1.30 1.7 3.3 6.19 17 SPRINGOALE 2.9 6.11 HE 13 22:10:24 37.163 116.752 0.5 1.94, 0.8 163 ACI 1.63 2.07 1.41 1.6 13 SPRINGOALE 6.6 12 TULE CANYON L. 14 6:18:45 37.283 117.607 6.3 0.63 6.4 88 ABI-1.28 1.55 1.26- 1.7 0.16 14 2:41:34 37.161, 116.753 6.5 2.13 6.7 163 ACI 1.35 1.31 0.93 1.0 3.6 0.12 13 SPRINGOALE HE 14 7:25:6 -36.691 116.268 8.6 1.53 3.9 2066 01 1.24 1.30 6e.85 5.8 6.14 15 STRIPED HILLS 14 17:41: 5 37.165 118.751 6.7 2.51 6.8 184 ACI 1.42 1.49' 1.05 1.6 3.6 6.13 16 SPRIHGOALE HE 1.01. 15 2:;6:43 36.680 116.243 0.5 266 COl 1.17 1.49 0.97. 1.0 7.4 6.06 10 SPECTER RANGE W 15 12:24:18 36.690 116.277 6.7 0.99. 0.6 20e- AOI 1.19 1.45 1.C3s 1.0 5.8 6.11 12 STRIPED HILLS 15 13:45:12 37.312 117.579 0.3 1.86 6.8 1;12. ACi 1.85, 0.96 1.65, 10.7 0.07 10 TULE CANYON , 186 7:58:54 38.687 116.261 0.6 1.54 2.9 245 801 1.15 1.25 0.80 1.0 6.2 6.08 13 STRIPED HILLS 18 8:43:50 36.688 116.275 0.6 1.77 1.9 229' AI 1.68 2.13 1.44 --1.6 6.1 0.08 11 STRIPED HILLS 16 11:26:14,- 37.449 116.389 2.3 9.37 4.7 297 801 1.78 2.76 ',1.59 , 1.7 25.2 6.20 16 COLD FLAT EAST 117.375 0.6 7.45 2.4 156 DCI -1.22 0.92, 0.64 16.7, 6.16 8 WEST OF GOLD MTN 16 16:30:12 37.183 SW 17 17:44:34 37.004 117.626 1.6 7.00 4.5 194•- 80 1.26 6.80 1.14 24.9 6.13.•9 LAST CHANCE RANGE 18 5:35:20 37.132 118.002 2.0 6.91 2.1 245 DO 1.76 1.80 1.75 1.9 33.5 0.19 11 *e*REGIONAL*** 18 6:50: 9 36.821 115.998 1.1 0.86 1.4 194 DOI 8.89 0.62 13.1 0.22 8 FRENCHMAN FLAT 19 22: 5:28 37.174 116.750 1.3 6.78 0.4 246 BOA 0.53 3.7 1.19 , 8 SPRINGOALE NEk 20 2:55: 8 37.164 116.754 0.5 2.93' 0.6 164 ACI 1.25 1.27 0.60 1.1 3.2 0.12 14 SPRINGOALE HE 20 15: 1:18 36.714 116.2e2 1.6 4.43 2.1 227 DOI 1.12 1.34 0.82 1.1 7.6 0.21 I1 SPECTER RANGE No 21 12: 3:59 37.164 116.747 0.3 1.56 0.5 162 ACi 1.58 1.83 1.36 1.7 2.7 6.08 13 THIRSTY CANYON NW 21 23:45:14 37.567 117.167 0.6 2.36' 4.8 128 DCI 1.40 1.44 1.57 24.3 0.15 15 RALSTON 22 3:19:25 36.757 116.248 1.1 4.82 0.9 l186 DCIl .69 1.24 8.68 0.9 2.7 0.17 11 SKULL MTN 117.998 1.1 " 4.68. 249 COI 1.5a" 1.56 1.52 1.9 32.6 6.13 16 JOSHA FLATS, 22 17:58:47 37.141 16 HIKO NE 23 8:39:44 37.768 115.652 0.5 5.70 2.7 :117 9O1' 1.29 1.31 1.25 11.9 0.13 23 12:30:16 37.164 116.751 8.3 6.77 0.2 16A ACI 1.49 1.55 1.27 0.9 3.0 0.09 16 SPRINGDALE hiE 10.9 0.16 12 WEST OF FURNACE CREEK 23 12:31:15 36.415 118.982 6.8 11.69 '1.3 89 BAI 1.50 1, 1 1.60 1.5 .* .7 * 7"ý r - 1991 LOCAL HYPOCENTER SUMMARY - SGO EARTIHQUAXES 'STAND ,- STAND' AZI "000 DEL-' ~~ DATE- TIUt" LA TtUDE LONGITUDE ERROR DEPTH ERROR CAP 12S MAGNITUDE ESTIMATES MIN RES. PH. U.S.C.S. (UTC) ' (DEG. N) (DEG. -A) H(KU) (KM) Z(KM) (DEG) Mco Md MLh MLv MLc (kid) (SEC), UADRANGLE, ' I' OCT -23 i2:35:27 37.i62 •0.53 I.6 0.6 ' 163 AC1 1.51 1.65 1.34 0.9 3.6 o.6o15 SPRINGDALE NE 24 " 6:41:25 "36.816 '.115.930 8..4 "117:178 8.93 1.5 :184 ADI40.91 '9.58 17.0 0.08'- 7FRO4CHMAN FLAT '25 '8:47:40 37.566 :6.7 ,0.77 1.4 -126 BCI 1.22 '" 1.15 1.22 23.6 6.19 13 RALSTON,, 27 '1:16:14 36.332 A116.239 ca , 1.47 -.1.1 265 ADI 1.20 1.33 0.97 19.1 0.11 14 SPECTER RANGE NW '27 '1:22:18 36.636 "116.227 0.9 1.76 -1.1 -298 56. 646 :ADI 1.37 1.80 1.08 1.3 10.2 0.11 12 SPECTER RANGE W 27 "1:42: 9 '116.254 '6.7 4.31 0.7 283 ADI 1.42 1.31 0.78 1.2 7.7 0.06 10 STRIPED HILLS 27 "4' 75. 5 356.643 017 '13.56 1.2 279 AoI 1.66, 0.56 "7.5 0.06 9 STRIPED HILLS 27 ' 5:52:57 36.642 116.261 -5.9. 5.17 0.8 279 "ADI 1.36 1.48 1.11 1.2 7.1 0.68 10 STRIPED HILLS 27 9:29:56 36.641 116.245 6.4 2.25 0.3 285 AoI 2.69 0.92 1.3 8.4 6.63 9,SPECTER RANGE MW 27 10:33: 1 356.647 116.256 0.9 -0.17 6.7 276 ADI 1.26 0.35 7.5 0.65 16'STRIPED HILLS 27 15:49:17 36.632 116.238 3.9 , 0.65 3.2 296 COD 1.51 , 0.60 11.3 9.9 0.13 9 SPECTER RANGE IW 25 ' 4:25:40 37.527 115.120 0.6 5.09 2.4 165 OCI 1.07 1.09 0.95 14.7 6.08 7 HIKO SE 57'.732 31 23:14: 5 116009 "0.9 -•.60 6.9 141 AC-1.61 1.40 '1.69 2.8 6.4 0.14 "9 MONOTONY VALLEY NOV I 5:' 7:18 37.221 117.360 0.6 9.22 a 1.1 156 ACI 1.67 0.68 0.87 12.7 6.69 a COLD MOLUNTAIN "53 13:38:11 37.198 117.595 6.6 7.79 0.9 151 ACI 1.62' 1.79 1.8 5.9 0.14 15 SAND SPRING, 4 3:56:22 37.391 115.471 0.4 4.25 9.3 -168 CCI 14,43 .1.57 1.9 27.5 0.09 t7 CRESCENT RESERVOIR '4 10:5:58 37.451 115.823 0.6 4.66 2.9 119 BCI 1.25 1.46 1.28 13.7 0.05 6 CATTLE SPRING 4 22:32:57 37.764 117.687 2.5 2.05 7.4 174 CCI 1.63 2.04 1.77 2.0 16.4 0.21 10 LIDA WASH M, 5 '7:20;23 37.1ig 117.841 6.2 7.25 2.7 252 001 1.28 1.14 1.41 17.9 0.15 10 EASi OFrJOS`HJA FLATS 6 5:35:7 36.847 116.272 6.3 0.43 0.3 95 681 1.20 1.05 0.8 1.3 4.3 6.15 25 GEORGESWATER 38.885 6 6:11:16 116.363 0.4 16.45 0.5 ý41 8AI 1.64 1.82 1.25 1.7 2.6 0.15 33 T~OOPAH SPRING, ;,, 6 14:49:18 37.183 117.416 6.4 0.01 6.5 122 ACI 1.03 1.10 0.79 19.2 0.11 14 WEST OF GOLD MTN -7 2:46:27 37.088 115.112 1.4 '9.09 1.4 286 B0I 1;77 1.52 1.40 1.7 11.2 6.12 8 LCWER PAHRANACAT LAKE SE 7 2:47:13 37.088 115.101 6.6 6.43 1.2 137 BCI 2.75 3.59 3.0 11.8 0.21 41 LOWER PAHRANAGAT LA.E SE 7 '3: 5:37 37. e69 115.136 0.3 9.66 0.5 221 ADI 1.55 1.63 1:4e 1.5 9.7 .6.3 7 LOWER PAIIRANAGAT'LAKE Sw 7. 5: 9:' 6 36.844' 116.273 6.3 1.57 3.8 97 BBI 1.61 6.76 0.65 4.4' 0.12 17, GEORGES WATER 8 12:32:23 36.848 11.240 0.4 5.34 1.1, 113 AB3 1.24 1.15 1.80 1.2 6.40.10 16 SKULL UTN 8 22:39:55 37.798 114.722 1.0 2.68 3.3 257 EPI 1.42 1.02 21.3 0.68 7 THE BLUFFS 9, 6:55:29' 36'725 116.246 0.6 6.81, 0.6 197 Aol 0.88 0.56 3.9 0.10 11 SPECTER'RANGE MW 9ý 10:12:45' 37.619' 117.859 1.9 7.e0. - 226 COI 1.23 1.22 1.37 30.3 0.21 10 EAST OF,:WAUCOA SPRING 10, 1:24:40! 37 626' 117.849 1.0 6.72 4.5' 93 80I 1.44 1.53 1.7 4' 29.2 0 .06 8 EAS T OF WAUCOBA SPRING 10' 10" 11:58:W611:39:471 37.219 117 337; 0.6' 1e;58 1.4, 96 ABI 1.32 " ; 1.29' V.5, 11.5 0;14 11 COLD MOUNTAIN 37.219" 117.348' 6.2 8.13, 0.64 94 Aol' 1.33 1.26 1.6 12.140.06 13 COLD MOUJNTAIN 10, 12:13:57' 371219 117.348 0.4. 7.42, 1.2 93 A81 1.16 1.27 0.96' 12.1'0.1016 COLD IEX*NTAIN 10 16: 1:46 36;460" 117.6261 6.8 11.76 ' 1.1 10o 681 1.65 173' 1!4" 6.8 0.16 10 DIIGRANT CANYON 106 16:11:42, 37:419W 115. 023 2.3 4.46 1.2 191' 001 1.35 0.83 1.06 1.2 2.8 0.19, 9 ALAIO HE, 10-'19133: 5 36 -7560i 116'674' S 0 .6, '138 ACI,1.34- 1.41,' 0.98 1.6 "16.1 0.18'15 CARRARA CANYON 10 23:J4:40 37.612" 115.0689 6.7 e1.7 2.5,' 122, 6CI-1.07 0.78 6.97 14.1 0.17 9 HIKO SE 11 4:30: 6 37.974 116.820 0.7 2.38 4.9 158 oCI 1.66 1.47 36.2 0.18 12 REEDS RANCH 12 23:59:39 36.631 116.616 6.3 10.84, 0.6 133 ABI 1.34- .1.16 1.55 1.6 5.5 0.06 13 CAM DESERT ROCK 13 18:13:26 37.324 114.674 1.0 3.42 - 296 CDI 1.80 1.84 1.76 31.7 6.68 8 ELGIN SW 14 9:46:46 36.647 116.261 6.5 5.46 0.6 249 ANo 0.90 0.64 7.6 0.06 16 STRIPED HILLS 14 10:23:45 37.085 115.122 1.4 9.92 1.3 248 601 1.86 2.68 1.79 1.8 10.9 0.16 11 LOWER PANRANAGAT LAXE SE 14 10633:12 37.079 115.128 1.7 10.44 1.4 286 80I 1.61 1.66 1.41 1.8 11.3 0.12 7 LOWER PAHRANAGAT LAKE SW I' S * j a' .5 .. *1 1 1 L L S ,-1 STAND STAND AZI DATE - TIME LATITUDE LONG ITUDE ERROR DEPTH 12S MAGNITUDE DEL- R s (UTC) (DEG. N) (DEG. W) H(IG) ERROR GAP MIN RES. PH. U.S.G.S., (KU) Z(KM) (DEG ) UCo Md ESTIMATESMLh MLv ULc (Ku) (sE) QUDRNLE NOV 14 ,16:30: 2 37.'240 116.501 6.8 6.87 1.7 '161 15 2 ACI 1.07 1.26 0.98 1.41•. •1.8 0.12 2:25: 37.377 115.237 8.1 7.51. - 232 DOI 1.31 1.18 1.6 60: 146 ASHTHIRSTY CAYoN 1S -4:29:29 37.258 '115.3,8 2.8 2.1 SPRINGS 3.31 231 CoI 1.19 0.93 .1.7 IS .,7: 1:57 37.378 115.237 0.6 4.93 4.1 6.10 8 DEAD HRSE'FLAT 5.3 135 CCI 1.37 1.11 1.30 1.8 16.7 15 7:37: v 36.742 115.970 0.3 77.32 1.0 131 6.11. 2 ASH SPRINGS 15 ABI 1.84 2.04 1.74 1.7 9.6 0.06 12 MERC•RY 7:39:44 36.742. 115.962 0.4 1.1 134 ABI 1.39 9.61 0.95 1.47 1.68 9.0 .16 13 MERY 15 7:59:55 "36.733 115. 988 6.4 9i.36 6.6 ACI 1.07 0.89 15 16:59:25 36,743 115.972 0.3 5.35 166 8.1 0.04: 8 OMRMRY 0.9 131 AB! 1.11 6.72 9.2 15 .18:22:42 37.137 117.058 L.5 4.00 9.6 144 0.05 9 MERCURY:. Ccl 1.65 1.6 17.3 6.11 16 8:22:35 36.931 116.182 0.6 11.07 1.2 111 ABl 1,31 11 BONNIE CLAIRE 6.86 0.40 8.6 0.12 It MINE 16 16:5: 8 36.710 116,232 1.4 5.57 1.8 214 301 1.04 MTW' 16 21:47:37 0.63 1.0 5.1 0.21 12 SPECTER 37.928 116.123 6.3 1.73 1.6 122 BCI 2.35 RANGE NN 3.14 3.1 24.8 6.15 38 FREDS WELL 17 8:11:16 36.602 116.28a 5.6 0.42 3.6 298 COI 1.67 18 13:22:59 37.431 115.473 6.8 6.65 6.7 0.14 12 SKELETON HILLS' 13.96 3.7 109 Da1 1.35 1.30 1.31 20 18:49:*S 37.251 116.393 1.4 19.95 24.9 0.15 9 CRESCENT RESERVOIR 1.6 208 801 1.50 1.31 2.4 6.5 21 4:16:68 37.288 117.533 0.3 '8.81 0.7 86 0.24 15 SILENTBUTTr ABI 1.45 1.24 1.54 1.5 11.7 6.67 21 4;54:19 37.154 117.394 7.80 1.0 125 ACI 1.16 11 TULE CANYON 21 14:55:27 6.3 1.13 6.84 17.8 6.06 0 WEST 36.647 116.298 0.4 5.01 0.5 131 ABI 1.28 OF GOLD MTN 1.85 1.11 1.2 3.7 0."9 16 STRIPED HILLS i, 21 23:24:40 38.691 115.569 3.9 0.93 2.9 300 COI 1.70 1.29 2.1 cg 22 5:16:37 35.900 116.816 1.4 4.78 21.6 0.10 10 HEAVENS WELL 1.5 270 901, 1.78 1.62 1.54 7.2 23 9:15:26 36.528 116.011 5.7 12.19 1.1 251 DOA 0.13 9 WINGATE WASH 23 13:41:55 6.68 12.9 0.20 9 POINT ROCK 38.840 118.813 7.000. - 286 ADA '0.36 OF 24 0:46: 4 38.688 25.6 6.08 4 CANE SPRING 114.756 0.6 -1.37 0.4 197 ADI 2.63 3.17' 24 11: 5:29 37.319 115.106 1.6 2.44 2.8 16.2 6.08 16 BOULDER BEACH 6.16 1.8 158 ACI 1.50 1.29 1.5 16. 9 6.11 9ýA LAMO 24 17:39:42 36.404 115.737 0.5 11.68 S.E 25 1.1 152 AC' 1.31 1.00 1.05 8:34:39 36.744 116.255 2.5 4.27 1.5 309 I'.3, 18.3'6.67 25 10:17:59 CDA 0.32 1.5 6.16 1S'CDLD"CREEK8 36.445 115.871 4.2 14.98 3.2,' 299 CO^A 0.98 STRIPED HILLS 25 10:20:28 36.328 115.899 1;. -0.51 21.-60,.17. 16. WILLOW PEAK, 25 1.0 286 BOA 6.768 26.8 10:21:55 36.741 116.274 1'44 - ADA 0.62 5 NIAVI WASH - , 25 16:23:27' 6.3, 243 0.93 6.2 0.03 36.467 115.928 12.74' 7.9 304 WOA 1.33 4 STRIPED HILLS 16.1 6.19, 9 MT STIRLING, 25 10:48:12 35.469' 115.814' 6.4 2.29. - 314 D6A *11.28 I> 25' 10:59:26 36.472* 115.815m 26.2 0.20 6 WILLOW PEAK 5.6 2.19. - 301 COA' 0.94 25 11: 4:14 36.438' 115.721 26.2 0.63 5 WILLOW PEAK 6.1 7.66. - 313 WOA 1.01 25 15:41:,7 36.777 116.273' 6.5 34.4'0.07 SCOLD CREEK 25' 4.65, 1.I .132 ABI, 0.68 0.44 19:31:17W 35.913 115.469 2.6 2.49 10.7 262 3.8 6.60 10 GEORGES WATER 25 23:24:42o CDI 1.80 1.41 1.87 46.4 0.29 1I'COTTbONOO 36.624 116.433 1.9 6.78 1.5 270 ol11.27 0.62 PASS 1.5 8.6 0.11 11 SOUTH OF LATIROP WELLS 26 12:18:54 37.229 117.336 1.0 9.49 1.9 89 e8 0.99 27 3:50:14 37.813 114.690 1.42 0.98 10.8 8.21 11 GOLD MOUNTAIN 1.2 3.61. COl 1.25 1.01 1.21 29 2:34: 2 37.383 115.249 9.4 4.50*. - 1267 23.4 0.13 8 THE BLUFFS 236 DOI 1.36 1.55 1.12 29 12:51: 8 36.052 114.727 1.3 3.49 1.4 17.8 0.17 7 ASH SPRINGS 29 13:31:36 1.9 201 130I2.21 2.18 2.27 2.2 14.7 6.26 37.594 117.036 0.6 8.94 3.8 145 OCI 1.46 17 HOOVER DAM 34 6:45:56 36.739 116.215 1.82 1.48 28.2 0.11 12 STONEWALL SPRING 0.3 5.58 0.6 36 SAI 2.82 .44 2.9 5.1 0.17 52 SPECTER RANGE NW 30 14:21:59 36.812 116.089 0.4 6.76 1.4 108 ASI 1.99 2.44 30 18:43:25 16.728 116.195 2 1.62 1.5 8.5 6.1318 CANE-SPRING I.e 5.09 1.2 226 AD1 1.01 1.92 1.33 1.4 7.1 0.14 13 SPECTER RANGE W :: ) . 92 * 2 • FIRM __ 1991 LOCAL HYPOCENTER SU.LARY - SOB EARTHOUAJ(ES DEL- RMS #N STAND STAND AZI 000 UIN RES. PH. U.S.G.S. DEPTH ERROR GAP 12S MAGNITUDE ESTIMATES DATE- TIUE LATITUDE LONGITUDE ERROR ULh MLv ULc (KU) (SEC) OUADRANGLE (UTC) (DEG. N) (DEC. W) H(KI) (KM) Z(t.) (DEG) 1cc Ud AD[ 2.53 1.4 2 2.0 6.9 6.14 14 SPECTER RANGE NW NV 30 19: 8:46 36.733 116.196 0.9 5.96 1.0 223 1.68 NV 11.06 2.2 159 DCI 1.43 1.4 3 26.3 0.12 9 REVEILLE PEAK DIEC 1 23:47:54 37.913 116.174 0.7 1.I6 16.3 6.59 6 MELLAN 2 8:42:42 37.634 116.507 9.6 6.ee. - 126 DCI 2.22 2.0 le 881 2.12 2.6 '3 2.2 12.5 0.20 14 ASH SPRINGS 2 12:13:45 37.385 115.189 6.7 9.51 W 4.96 0.6 212 ADI 1.33 1.95 1.e '9 2.0 5.3 6.69 14 SPECTER RANGE 3 3:58:37 36.733 116.214 0.5 0.9 4 20.9 0.16 6 COAL VALLEY RESERVOIR 3 4:25:50 37.974 115.355 1.5 2.99 8.1 260 CDI' 1.02 2.9 126 DCI 2.15 3.04 2.6 '5 2.3 24.5 6.69 13 REVEILLE PEAK NW 4 13: 8:34 37.926 116.129 8.3 2.63 SPRING 1.83 2.2 136 BCI 1.06 6.7 '6 9.6 0.17 15 CANE 5 2: 5:56 36.801 116.084 P.5 6.6 .3 9.6 0.18 13 CANE SPRING 5 11: 1:55 36.802 116.083 0.7 4.63 5.9 136 CCI 1.61 6.6 218 ADI 1.36 2.16 1.3 7 2.0 6.0 6.08 15 SPECTER RANGE MI 5 14: 0:18 36.730 116.207 0.5 5.82 6.68 11 MIITE SPRINGS SE 6.49 1.0 128 ABI 1.18 6.82 1.4 5 1.4 10.2 BLOTCH 7 4:26:59 37.622 115.765 0.3 2.29 2.2 3 2.3 79.4 0.31 16 LITTLE LAXE 7 6:41: 4 35.921 117.764 3.7 4.68. - 291 COI 2.14 5.e6 2.0 137 ACI 1.36 1.22 6.9 9 1.4 9.1 6.12 22 CANE SPRING 9 8:34:20 36.869 116.0853 0.3 1.1 9 1.6 14.8 6.69 14 FRNCHMAN FLAT 10 4:10:12 36.809 115.986 0.4 1.78 1.2 155 ACI 1.25 15.15 0.9 124 AS! 0.8 89 22.6 6.64 6 MUJRPHY GAP 16 18:54: 6 37.866 115.493 6.3 1.12 6.991 1.4 6.6 0.11 7 FOSSIL PEAK 11 6: 2:42 37.726 115.248 1.8 6.85 2.6 195 BOI 1.19 4.28 3.8 139 BCI 1.62 0.9 91 9.7 0.17 13 CANE SPRING 11 17: 5:43 36.865 116.886 0.6 2.69 1.1 3 2.0 6.1 0.11 12 STRIPED HILLS 11 22:17:37 36.693 116.306 0.8 4.83 1.6 181 ADI 1.85 0.9 98 1.5 8.4 0.12 15 CANE SPRING 12 6: 2:28 36.812 116.096 6.4 5.92 1.9 165 AI! 1.14 1.6 196 ADA 0.44 17.4 6.07 16 SPECTER RANGE SW 13 3:53:30 36.592 116.157 0.7 1.85 NE 1' 7.46 3.9 112 581 1.21 1.07 1.1 6 7.9 0.23 8 HIKO 13 15:31:47 37.667 115.024 1.2 11.4 0.16 7 BUCKBOARD MESA 13 23:22: 4 37.606 116.264 5.6 2.26. - 282 DDA 0.74 15 SE 8.43 7.1 269 COA 1.26 32.5 0.12 FRENCHMAN LAXE 14 1: 2:42 36.813 115.868 1.6 8.9 0.68 6 BUCKBOARD MESA 4, 37.037 116.287 2.5 9.58 2.3 298 COA 0.32 IS 3:13:25 At.-. BUCKBOARO MESA 1.05. - 200 COA e.71 8.3 0.15 11 15 3:14:21 37.006 116.354 6.7 PINNACLES RIDGE 4.94 3.3 ,140 BOY 1.05 7.6 6.14 9 15 16:51:57 36.959 116.477 1.6 PINNACLES RIDGE 4,' 4.69 2.0 192 BOY 6.77 5.7 6.68 14 15 16:15:23 36.948 116.473 6.6 1.6 6.08 7 STRIPED HILLS 15 23:27:14 36.734 116.268 1.5 0.96 0.4 312 BOA 0.64 8.76 1.9 250 BOA 1.34 6.7 0.14 11 SXULL 1TH 16 2: 2:58 36.799 116.139 1.2 8.5 6.69 12 CANE SPRING 4 16 3:56:57 36.768 116.121 6.6 1.93 6.8 261 ADA 1.66 5.21 0.5 270 ADA 0.48 7.5 8.62 7 CANE SP'ING16 S16, 4:34:53 36.805 116.114 6.3 .,+6.2 0.12 12 SKULL MTH,,-, 16 '.5:22:43V 36.866 ', 116:132 1.1 3.62 1.7, 257-. BOA 6.99 2.22 1.8., 272ýCBOA 0.59 - 6.8,6.18 9 CANE SPRING.. 16 5:26:41 36.813 116.113 1.9 ,16.2 0.12 12 FRENCHMAN FLAT 2.3 '294 -, -Cx"A . 1.68 16 '6:38:4,, 36.847 ' 115.987 2.9 6.52 3.26 6.7 e164-ACY 6.:71 .16.3 6.68 It PINNACLES RIDGE 17, 5:14:50- 36.942 116.467 0.4 15.9 0.15 11 SPRINGDALE 17, 6:13:27 37.017 '116.801 1.1 23.16 1.9". 133 j BOA 6.83 6.71 1.2 126 ACA 1.71 16.9 0.11 0 CR004 RANGE NE 17 12:59:19 37.487 115.536 6.6 5.760.12 9 SKULL MTN 17 20:14:58 '36.815 "116:128 '-1.5 ,14.16 1.4 265 BOA o,0.64 ,'2.64, '0.8 -'285 'ADA,, 6.74 7.2-:.:7 9 CANE SPRING 18 2: 6:12 36.866' '116.114 'S.7 -7.5 6.11'10'SXULL MTH 116.163 1.6 4.74' '1.4 '247 ADA 0.64 18 9:28:28 36.787 7.9 6.16 16 MINE MTH 21 14:19:28 36.988 116.165 1.6 4.50 1.4 246 BOA 0.68 22.6 6.12 10 GROTTO CANYON 21 18:54:32 36.556 117.015 2.0 10.56 3.1 ',,226' BOA '1.26 11.0 8.13 8 MINE 11TH 1.8 2.63 2.4 286 BOA 6.46 23 14:15:16 36.979 116.129 6.2 0.17 11 SXULL I1TH 24 5: 3:42 36.862 116.247 0.8 2.96 1.6 130 BOA 6.61 *1 I-- . B Sr ...... , + -. .I t 1991 LOCAL -YP4T.OCEdRSd.RI Y - SG8 EARTHQUAKES T4II SSTAND AZI 000 DEL- FOS IN MIN RES. PH. U.S.G.S: LATITUDE LONGITUDE IERRI R DEPTH ' ERROR GAP 12S MAGNITUDE ESTIMATES DATE - TIME ' MCC MLh MLv MLc (KU) (sEC), QUADRANGLE (UTC) (DEG. N) (DEC. W) I) (KM) Z(KQ) (DEG) Md 1.2 0.94 12.2 6.13 16 CARRARA CANYON DEC 25 0:39:19 36.864 116.736 0.7 7.25 1.8 229 BOA 5.18 3.6 241 BOA 0.77 19.3 0.07 16 L[ELAND 26 0:17:38' 36.539 116.606 16 RAINIER MESA 116.204 1.0 5.21 5.6 132 CCA, 0.79 13.7 6:23 25 '-5:25:27 37.159 BUCKBOARD M4ESA 110.257,'. 1.1 S4.60 . 2.5 122 BSA, 0.76 4.7 6.26 12 26 18:18:15 -37.602 2.5 22.6 6.19 EAST or ECHO CANTON 27 11:29:60 135.498 116.6800 3.26e - p266 Cr. A 0.93 DCA 14.8 6.15 6 OIAK SPRING BUTTE *5 30 15: 3:56 537.314 118.101, 1.11 -0.63 3.4 156 0.74, 0.85 8.6 0.13 16 BUCKBOARD'MESA 31 18:11:53 37.108 11o.288 0. 1 0.96 1.1 161 ACA Sf 41' I N # '5.-I. ,,p L,. k,. -- ' , ) I '.-... -. Appendix B - ...... Chemical explosion location data for 1991 - - The southern Great Basin of Nevada is seismically active from both natural and manmade sources. Seismograms from chemical explosion sources that are detected by the SGBSN are scaled Sto provide information on the accuracy of the crustal model and location algorithm used by the SGBSN. The following organizations have been contacted and have provided helpful information on source locations, times, and in some cases, TNT-equivalent source size: (1) Bond International Gold, Denver, Col. Blasting at Ladd Mountain, Nev. (Beatty iopographic quadrangle), daily on weekdays, 4 PM to 5 PM, with limited weekend blasting. Approximate coordinates, 36.89°N., 116.82°W. (2) Chemstar, Inc., Las Vegas, Nev. Blasting at two limestone quarries, one in th-e Dry Lake, Nev., quadrangle, and one in the Sloan, Nev., quadrangle. The Dry Lake quarry coordinates are 36.3610 N. latitude, 114.915°W. longitude. (3) Cyprus Tonopah Mining, Tonopah, Nev. Blasting in the San Antonia Mountains (San Antonia Ranch quadrangle), weekdays, usually in the morning. . (4) Frehner Constru-tion, North Las Vegas, Nev. Blasting at limestone quarry in Sloan, Nev., quadrangle. (5) Saga Exploration Co., Beatty, Nev. Blasting at Bare Mountain, Nev., usually early to late afternoon. (6) Gold Bar Mine, Beatty, Nev. This mine is about 10 km northwest of the Bond Bullfrog Mine, in the Bullfrog Hills. Less active than (1), blasting occurs from early to late afternoon. A number of other organizations also known to be engaged in blasting in the southern Great Basin of Nevada have not been contacted. Column headings for this Appendix are identical to those for Appendix A. The depth of all blasts is at the surfa~ce (plus < 100 feet, usually), but in many instances, hypocenters have been located with depth as a free parameter, to examine the location algorithm'and velocity mod:l. If thi hypocenter depth is reported as -1.00 to -1.10 km, it was fixed at that value during hypocenter determination. All other depths are freely determined. If the letters "PB" follow the depth estimate, the eventis a probable blast, but just enough ambiguity was present in the seismograms to prevent a certain judgment. Data from known chemical explosion sources are not scaled from Develocorder films, so "gaps" in the explosion record may -exist for periods of isniiiiic•ci-rrip-iter do-fwitime. Errors in hypocenter3 for chemical explosions are not'necessarily indicative of errors in earthquake hypocenters. One reason for 'relatively large depth-of-focus error for explosions is that S-wave arrival times are often impossible to determine from such sources. As is well known, S-wave arrivals from near-source stations often provide important information for constraining focal depth. The Bullfrog Hills blast hypocenters reported here are usually from "ripple charges" that efficiently 'gzierate S-wave coda. Hypocenters from those sources generally settle at very shallow depths, although competing hypocenters in the 5 to 10 km below sea level range ar'e frequently encountered. The nearest station to these Bullfrog Hills blasts is about 20 km away, so the station-near-source constraint is absent. 59 (t -- .-'. - -. - - - Ch"MASI Ua..U I "I ""7 ' 0 i 7 SrnSIORAHC STATION 0 cart ORTMT o25 5, 1tohn "- C 1(I0 0 20 Seag ( 30 I O0 1 il < 20 0 30SuMeg Figure BI. Epicenters for known and suspected chemical explosions detected by the SGBSN /or the calendar year 1991 are plotted in map view. 60 i I 1991 LOCALHKYPOCENTER SLUAAR -: 506 CHEMICAL ECXPLOS!ONS 'I 'S STAND AZI DEL- FU3 IN 11 , " - .I I 1 STAND , , , '12S MACNITUD ECESTIMATES MIN , RES, PH. U.S.G.S. ERROR GAP DATE - TIME*' LATITUDOE LONGITUOD ERROR DEPTH (DEG) ' oo t . ,U MLh MLv ULc (KU)) (SEC) CJADRANGLEQ- (UTC) " (DCG. H) (DEG. W) ,' H(KI,) (KM) Z (OM) 18 BEATTY, 0.4,. -1.i6L' :e.7' 122 ACI' 2.36 1.66 1.76 '1.2 26.18'.14 JAN 1 23: 4:19 36.895 116.816 1.9 26.1 6.1317 BEATTY 116.8186+ 0.4 -1.606L 8.6 124 ACI,2'21 1.57 1.75 . 36.892 15 BEATTY 2 23: 7: 8 0.7 124' 1 1.88 2.6 26.3 6.14 3 23: 1:55' 38.894 116.826 6.4 '-1.600L ACI 2.161 1.8 26.3 6.22 16 BEATTY ,119 1.68 1.86 5 23:31:58 . 36.902 116.813 e.s -1.606L 0.7 : 1.83 2.0 26.8 6.17 15 BEATTY" 118.821 6.4 -1.606L 6.7 123 D•C 2:36 7ý 23:21:55 36.898 1.1 -0.82P6 2.2 136' 'WI 1.47 " 6.80 1.1 9.2 6.19 11 EAST OF BEATTY M4TH 8 20:49:35, 36.8885 116.624 2.65 2.1 19.7 8.1416 DEATTY'l *' 2.36 1.71 8 23:14: 6. 36 :891 116.8147 8.4 ,'-1.606L .0.7 123'- ACI BEATTY, 1.1 124 'BCI 2.26 ' 1.61 2.06 19.7 0.23'16 9 23:32:52 36.888 116.817 0.7 -1.008L 14 BEATTY 0.9 121 'S1CI 2.49 1.94, 1.72 2.1 20.5 0.22 13-23:15:21 36.901 116.8175 6.6 -1.680L 1.67 2.0 20.1 0.13 17 BEATTY 116.815 6.4 -1.6061 0.6 122 ACI 2.32 1.72 14 23:30:51. 36.896 1.47 1.9 20.6 0.19 16 BEATTY' 0.8 125 "C! 1.51 ¶ 4,'4 15, 23:32:48a'36.892 116.824 6.5 -1.0061 0.12.13 BEATTY 0.4 -"176 ACI 1.46 1.13' 18.8 16 21:56' 5 '36.913 116. 843 6.3 -I.52P9 1.6e 1.62' 2.6 26.5 6.14 17 BEATTY 0.5 122' AC! 2.24 '* 16 ,23:33:52• 36.899 116. 81 0.3 -1.800L 6.20 17 BEATTY, 118.819 124 OCI 2.28 1.78 1.62 2.1 20.6 17 -23:20:540 3,6.896 6.6 -1.106L 6.8 2.1 26.0 0.14 13 BEATTY 0.6 -1.108l 0.8 '121' 'AC! 2.68 1.70 2.31 18 23:25: 9 36.895 116.5814" 0.79 19.1 0.16 12 BEATTY 21:41:49 36.965 116.844., 0.4 -1.066.6 .6 127 ACt 1.44 20 ACI 2.07 1.68 1.65 1.8 '26.2 0.13'16 BEATTYi 21 23:24:49:'36.896 116:17,' 6.4 -1.100L, 6.6 122 6.16 12MBEATTY 6.3, --e.966L 0.51 125' AC! 1.48 1.61 ' 1.4 ,19.2 ,22 -21:53:35 Zo6.967 116.841 20.0 6.14,17 BEATTY 116.826', 68L 125 "ACI 2.24.' 1.74,' 1.7 23 23:25:29,38.889 116.818+,, 0.51 -1:1 ' e.6 2.6 6.12'15 BEATTY 0.4 '-l:l60L 0.6 123:'ACI 2.34' 1.62 26.2 o% 25 , 0:18:4a8 36.895 1.88 2.1' 26.1 0.14,15 BEATTY.' 0.5 1.10e.8 126 AC! 2.16 1.73 25 0:43:48' 36.898 118.813 1.64 1.71 1.8 26.3 6.14 16 BEATTY 119 ,AC! 2.14, 4. 29,- 23:3e:59-.36.962, 116.813, 0.5 . -1.106L16.8 1.9* 26.3 0.29617 BEATTY,' 116.817',. 6.5 ,-1.006L0.7 , 122 BCI 2.29' 1.47 1.48/ FEB 4ý 23:36:45- 36.896, 1.66 1.89 2.0 29.6 0.22 16 BEATTY:% 5' 23:36:44',36.892 116.833,. 0.6 0-l.006L6.9 128 9CI 2.11,' 116.818 .1.78 1.8 26.5 6.18:16 BEATTY!' 6,.23:37j55, 36.9ie 6.3 "-1:008L 0.5"' 121 '"9CI2.39 BEATTY" 116.817 0.3 -1.0GL 6.5 123 AC! 2.28 1.86 2.03 2.1 261 0.1416 8,19:57:54- 38.893 116.,817 1.67 1.7d 2.6 26.0 0.14,17 BEATTY 9 1:25:54 36.892 0.4 -1.001 6.6 'S 123 AC! 2.21 116.813 6.4 6.6 176 ACI 2.36 1.67 1.9 26.2 0.13 16 BEATTY 11 .23:30:44 36.906 -1.0061 6.22:16 BEATTY 1168 822 2, 6.5 S-1.60L 6.9 126 NCI2.37 1.88 1.50 2.2 20.1 12 123:16:45 386.587 116.815_ 1.25 1.84' 2.1 20.3 6.16'16 BEATTY 13 23:14:42 '36.899, 6.4 -1.8081 06.7'' 121 BDC!2.35 116. 815? 121 2.20 1.56 2.0 20;1 0.13215 BCATTY:f:. 14,'23:38:54 ,36.896 0.4 +-1.606 6.7' ''ACI 116:824 2.32' 1.86- 1.24 2.6' 20.3 0.14'15,B.ATTY,' 16 0:48:44- 365189 0.5 -1.6l6L 6.8a 126 - ACI 116.844' 1'.32 6.68 • ,' 19.0 6.68,14 BrATTYt 16 21:51:521"36.906 6.3 -1;.0L"e,.5" 127''ACI 116.812 126 ACI 2.15 1.58 1.9 20.1 0.16 12 BEATTY 16 23:29:58. 36.900 6.5 -1.166L 1.4 26.1 BEATTY, 116. 821 1.7 1.6.TP9 5.5 125• CCI 2.21 ' 1.82 1.55 2.2 0.40,14 18 '23:59:38, 36.888 1.91 1.93,. 2.6' 19.6 6.14 16 BEATTY.,, 20 0:32:37 '36.893" 116. 811 6.5 -1.188L, 0.7 121 :ACI 2.37' BEATTY 116.817" 0.4 6.6 123 43AC! 2.29' 1.77" 2.06 26.1 0.12116 20 +'23:29:37' 36.894-, "-1.168L 1.86 2.0 26:0 0.12,14 BCATTY, 116. 814 6.5 -1.108L 1.0 ' 1214"ACI 2.40' 21 .23:34:39'-ý36.896 116.826' 1.71 2.2 ,26.4 0.12,415 BEATTY , 22 23:23:41 '36.895 6.4 -1.27PS 6.9 123' AC! 2.47 118.526 , 6.4 AC! 2.58 1.79 1.26 2.1 26.2 0.13 16 BEATTY 23 .23:44:36 36.893, -1.10L 6..6 124 BEATTY 116. 821• 6:4 2.788L 3.0' '122 ONI 2.56' 1.62' 2.1 26.7 6.15,16 26 0:11:39 36.899. 1.98 2.1 19.8 0.19 15 BEATTY 116.812 121 DCI 2.76 1, 26 23:24:35 36.895 6.4 -1.166L 6.7 2.14 1.9 26.2 0.08 15 BEATTY 27 23:49:39 36.905 116.809 e.3 -1.166L 0.4 166 ACI 2.40 116. 815 A.75, 2.6 20.1 6.12 13 BEATTY MAR 1 0: 7:30 36.896 e.5 -1.106L.-1.4 169,' ACI 2.24 .. . ' '' 4. ,,, +•+ 4 + + 1991 -LOCAL HYPOCENTER SI&4ARY - SCO CHDOICAL EXPLOSIONS STAND STANO AZI 0O DE:.- rs IN DATE - T!UE L.AT!TUOI E LONGITUDE ERROR 'DEPTH ERROR CAP 12S UAGCNTUDE CSTIWATES U!N , RES. PH. U.S.G.S. (UTC) (DEC. N (DEC. W) H(KM) (0.) Z(I.) (DEC) Ucv Wd MLh UL ULc (I U) (SEC) ,QUADRANGL MAR3 0:20:30 36.896 116.818 0.4 -1.1BOL 0.6 122 ACI 2.51 1.87 1.9 2 0.3 8.11 14 BCATTY 5 0:22:29 36.898 110.819 0.4 -1.900L 0.8 122 AC! 2.40 1.80,'2.0 2 0.6 6.1S,14.BRATTY .7 5 23:44:38 36.889 110.827 0.5 -1.0801 0.9 127 DC1 2.53 1.63 1.57, 2.0 2 0.5 0.1W,15 BCATTY 6 15:46:59 36.831 116.698 0.7 -1.30PS 0.6 231 ADI 0.99 0.48 7.4 0.68 9 CARRARA CANYON 7,' 0:32:27 36.895 1116.819 0.4 '-l.880 e0.60- 123 AC! 2.37 1.79 2.0 2 0.4 0.13ý15 BCATTY 8 0:13:27 36.891 116.824 0.5. -I.W01L 0.9 '128 SCI 2.43 1.54 2.1, 2 0.4'0.18517 BCATTY 8 23:33:35 36.897 116;815 0.4 '-1.806L 0.8 122 ACI 2.29 1.58 1.69 2.1 2 6.2 0.14,16 BEATTY 12 6: 7:32 36.889 116.823 6.4 -I.886L 0.7 ' 126 OCI 2.50 1.93 1.96 2.2,- 2 0.3 0.16 14 BEATTY 12' 23:28:35 36.893 -116.813 0.4 -1.08OL 6.9 122 AC! 2.88 1.52 1.9-1 9.8 0.12,13 BEATTY 14. 6:31:36, 36.89 118.823 6.5 -1.8081 1.6 125 BC! 2.69 2.28 2.1 2 0.3 0.18 13 BEATTY "14- 23:42:53' 36.895 116.819 ,0.5 -1.000L 0.9 ý123 ACI 2.09 1.61 1.9 20.3 0.13 13 BEATTY 15" 23:24: 3 '36.899 116.811 0.5 '-1.000L 0.8 126 0CI 2.48 1.81 '2.1 19.9 0.17 15 BEATTY 18 23:45:28 36.896 116.823 ' 0.5 -1.600L' 0.8 126 DCI 2.66 1.93 2.06-2 0.4 0.19 16 BEATTY 19 23:32:43 36.898 116.813 I 0.5 -1.001L 1.0 121 ACI 2.35 1.79 2.0. 2 2.1 0.12 13 BEATTY 21 1:12:19 36.889 116.818 6.4 -1t.68L 8.7 124 ACI 2.68 2.67 - 2.2 19.9 0.12.16.BRATTY 23 1:38:32 36.897 116.817 0.3 -1.680L 0.6 122 A'l 2.40 1.16 1.75 1.9 28.3 0.12 18 BEATTY 25 23:45:30 36.897 118.819 6.3 -1.009L 8.6 122 ACI 2.54 1.87 2.0 ý220.4 0.15.16 BEATTY 28 i:1:29 36.899 116.821 0.4 -1.006L 0.7 123 DC! 2.36 1.32 1.57 2.0 221.7'0.18 16 BEATTY 28 23:39:26"36.893 116.826 0.3 -1.08L0 0.6 124 DCI 2.38 1.84 1.62 2.2 20.3 0.17 14 BSATTY 29 "23:53:27 36.888 11. 822 0.4 -1.608C1 0.7 , 126 ACI 2.53 1.73 2.1 20.1 0.13 15 BSATTY 31 23:11:38 '37.012 116.718 0.5 -1.48PS 1.1 102 ACI 1.29 0.91 14.9 0.09' 9 THIRSTY CANYON SW APR 1 23:24:29 36.898 116.818 0.4 -1.60L9 0.7 122 ACi 2.50 1.57 1.64 2.0 20.4 6.14 16 SCATTY 3 0: 5:37 36.896 116.817 6.4 -1.060L 0.7 122 BCI 2.26 1.82 2.10 '2.2 20.2 0.18,15 BSATTY 3 23:49:26 36.895 116.815 6.4 -1.088L 0.7 122 ACI 2.58 1.28 2.0 20.1 0.15 17 BSATTY 5 0:38:23 36.893 116.821 0.4 -1.008L 0.6 124 ACI 2.51 1.46 1.66 2.1 20.4'0.12 16 BCATTY 6 18:18:24 30.895 116.820 0.4 123 ACI 2.49 1.28 1.55 2.6 26,4 1.14,15 BCATTY 8 -22:36:50 '36.897 118.819 0.4 -1.008L 0.7 122 SCI 2.23 1.28 0.07 20.5 0.15 13,BRATTY 9 118. 822 0.4 125 ACI 2.44 1.72 1.83 2.2 26.3 0.14 14 BSATTY 22:39: 7 36.890 ---1.008L1.0051L 0.79 22:39:15 36.898 118 .814 0.4 0.7 121 'AC 2.18 1.20 1.93 1.9 20.1 0.14 14 BSATTY 12 0: 1:18,36.094 S116.819 0.4 123 OCN 2.37 1.72 2.2 26.3 0.19.14 BSATTY 1.7 "• 116.816 S-1.60BL 12 22:40:35',-36.895 110 BCI 2.67 1.55 2.5 ,28.1 0.17 23 BSATTY *1.9, 19.5 0.16 19 BSATTY 15 22:29:29 36.893 116.869 i-.e8L8 0.9 84 9C[1.63 1.52 1.77 16 22:26:47 36.891 1168.818 6.5 -I.600L 1.2 124 ACI 1.84 2.5' 20.0 0.12,12 BSATTY 10 116. 813 17 22:32:11 36.889 0.3 -1.800L 1.4 62 AC! 1.78 1.81 19.5 0.13 18 BSATTY 18 117.618 19: 3.43' 38.035 116.819 8.3 221, DO! 1.09 15.7 0.25 7 TELESCOP POAX 18 22:31:17 36.883 6.6 -1.006L 1.2 59 Dc1 1.80 1.82 1.77 19.6 0.21, 17 BSATTY 116.8e9 19 22:43:17 36.897 1.0 -1 .080L 2.4 18 DCi 1.69 1.61 1.74 19.7 0.25 15 SCATTY 118.820 22 22:39:12 36.896 0.3 -1 .806L 1.8 79 ,ACI 1.93 - 2.6 20.1 0.15 18 CBATTY 23 118.814 22:22:27 36.890 116.815 0.4 -1.808L 1.1 79 ACI 1.83 1.82 2.6 19.7 0.14 23 BSATTY 24 22:27:36 36.891 0.6 -I .e60L 1.7 162 BCI 2.01 1.74 19.8 0.15 15 BSATTY 25, -1 .068L 22:39:16 36.894 116.813 0.5 -1.608L 1.4 79 DCI 2.16 2.63 1.57 2.5 "19.8 0.17 22"BEATTY 26 21:47:18 36.896 116.813' 0.4' 1.2 80 AC! 1.61 2.08 1.9 '19.9 6.12 15 BSATTY 29 18: 9:57 35.220 117.720 12.6. 0.0001, 9.92 329 00. 1.86 113.1 8.21 6 ***REGICCAL** 29 22:37:25 36.892 116.814 0.4 -1.880L 1;e - 68 ACI 1.72 2.603-1.9 19.8 0.12 19 BEATTY I 7 Njý Zn * 1991 LOCAL HYPCENTER SUIARY SCU CHEMICAL EXI0OSIONS STAND STAND AZI 000 RUS IN ERROR DEPTH ' ERROR CAP 12S UAGNITU ESTIM4ATESULh ULv 'ULc' S *A MINDEL-(Kla)'(SEC), RES. PH. QUAORANGLEU.S:G0S. DATE - TIME LATITUDE LONGITUDE H(KI) U:o IS (UTC) (DEG. N) (DEC. W) (KM) ',Z(KM) (DEC) APR 36 22:23:23 36.895 1 18:11 0. 6a -1.8081•, 2.8 DCI 1:45 1.46 19.8'0.14 8 BRATTY. MAY 1 22:22:20 36.898 116.813 0.5' -1.0011. 0.9 121 DCI 2.27' 1.eo 1.2 2.0 20.6 6.17 13 BCATTY 2' 22:54:18 36.892 116.815 0.31 -1'.0OL 6.9 123 AC1 '2.66 2.16' 1,42.1' 19.8 6.16 14'BrATTY 0.3" -1.6081 0.6 122, ACI 2.40 1.48 1.81 2.0 19.9 6.10 14 BEATTY 3 22:24:36 36.894 116.814 168 6- 22:18:57? 36.894, 116.847, 0.4 -1.083L. 2.3 DC| 1.74 1.89 2.5 19.3'0.14'18 BCATTY, 7 22:47:27- 36.893 116.819, 0.3 -1.0813 6.6 124 DCI "2.69 "1.19 2.2 20.2 0.22'15 BCATTY, 6.4 -t.eeoL' 6.8 8 22:30:20, 36.892 118.,21, 124, ACIV2.71' 1.42' 2.0 20:3 0:13 15 BEATTY " 9 22:10:54., 36.894' 116;817 6.4 -1.008L 6.6 123, ACI '2.16S 1.00' 1.50' 1.9 26.1 0.11*15 BCATTY 16 22:29:524 36.894 116.824 64 -1.666L 1.2 125 8CI 2.3V• 1.67' 2.0 2e.6 9.19 13 BCATTY 11 21:57:21 36.895, 116.812 6.4 -I.e6oL 6.8, 121 DCI 2.62 1.22 2.03 2.1 19.8 0.19 13 BEATTY 13 22:25:23, 36.894 116.815, 0.4 -l.e6OL e.8'0.9 122 AC! 2.42 1.91, 2.1X' 19.9 6.12 13'WBATTY 14' 23:29:256 36.896, 116.826 0.5 -i.eeeL. 126 601 2.63 1.61 2.1" 20.5 6.16 16 BCATTY' -l'.eeet" 9'7.' 15 22:53:23' 36.898 116.826 0. 4' 122 DCI 2.42 1.69 2.6 2066 0.20 18 BEATTY. 0.5 -Vt0081. 0.9'" 1 .69 17 0:14:17' 36.888 116.825' -1.660L 0.8' 127, DCI2.57 2.2 20.,4 0.1515 BSATTY 17 22:17:2r 36.900 116.815 e.4 -1.8081 6.7 121 BCI 2.31 2.0 20.3 6.23 14 BSATTY, ,-,26 23: 3:26 36.895 116.812 0.3 -1'.66 6O.90. 121 ACt, 2.58, 1.49 2.2 19.8 6.12 15 BSATTY 21ý 22:51:56^ 36.894" 116.824 0.5 -t.eeOL 0.7 125 WCI 2.51 2.69' 2.0 20.7,0.17 188BRATTY 0.4 -•I-'1.666L .eOBL 0.66.8 124 DCI 2.68 2.1,' 26.3 6.207' 16WBRATTY 22 22:17:28 36.893' 116.820, -160 .6. 23, 22:,6:46 36.894 116.811, 0.4 12 1 OCIx2.50 19.7 6:15'18 BEATTY, AC1. 2.71' 2.96 20.160.15 17 BSATTY 24 23:23:25 36.890, 116.820' 0.3 -1.00L 6.7 125, 1:4P• 2.6 w 28 22:25:48 36,896 116.822 8.4 124' BCI' 2.50 S1.2i 20.76.2615 BSATTY 226 601 1.38 0. 55 1.55 26.5 0.14 7 APEX 29, 20:-5:52, 36.373, 114.914, 2.2, -4.8661 1.4, 2.1' 6.5 164, 1.64' 20.:51.077 0 BSATTY 30 0:14:29 36.969i 116.8092 8.4k 156 cc I' 1:26d 36' 0:14:33 36.934. 116.831, -11.908L-1.6001 19.26.7 DCI 2.96: 19.6 0.25" 7 BSATTY 120 DCI'2.57' 2.0' 210.S"17 15 SCATTY'. 36 22:43:,!1 36.899, 116.813, 0.5 -1,66L 6.9' 1:62' 31, 23:.4:38, 36.892' 116.826W 124 8CI 2.64' 2.1 20.2-6.20 15•BEATTY' JUN 3 23: 9:26 38.895' 116.816 6.3 129S DCI, 2.78 2.9' 19.7 0.16 '14 BRATTY', 1.55 20 4 0.17 17 BSATTY 4 22:26:52 36.898 116.819, 6.4 -1.90681. 6.5 123 DCI 2.51 2.01.8? 5, 22:19:53 36.904, 116.815, 0.5 -1'.6061 6.6 168 DCI 2.461 1.59' 20.6 0.16'13 BSATTY 6 18: 9:60 36.418 114.851 10.1 2.4601' 27.4, 242 DOI 1.206 1.21"V, 29.3,0.37- 6'DRY LAXE 6 22:28:33 36.892 118.821 0.5 11. 124' BCI 2:57 1.95' 2:2' 26.3-0.18 14 BEATTY 7 23:49:35' 36.888 116.824 6.4' -1'.e609L 0.7 127: OCN 2.65 2.$, 20.3 6.17'19 BEATTY' 10 22:27:55 3.892' 116.822 0.4 -1. 606L 0.7 1251 ACl 2.57 1:56 2.4" 20.4 0.15 17 BSATTY' '.4 12 0: 5:55 36.897 116.815 0.4 6.7, 121 8C1 2.49 1.83. 2.,• 20.2 6.17 18 BSATTY 12 22:45:50 36.896, 116.821 0.4 6.7 111, 0C1,:2.36, 1..67 217 20.2 6.15 17 BEATTY) 13 22:25: 4 36.896 116.8208 0.4 0.7 t 231 DCI 2.48 1.91, 2.5' 20.4 6.19 17 BSATTY' 4*.J -1.80B1 6.5 14 22:22: 5 36.890 116.817 0.3 1241 AC612.49 1.50 2.4 19.i,0.11 :17---ATTY' ";,18 0: 3: 4 36.894 116.825 6.6 1.6 125 Oct 2.45 1.94 2.6 26.7 0.21 17,BSATTY .4 18 22:31:17 36.897 116.818 6.3 3.1 122' 6C1 2.61' 1.64 2.7 26.3 6.67,12 BSATTY" 26 23: 6:37 36.892 1 116.816 6.4 -1.606L 6.6,1 123 AC! 2.59 1.90 2.5 19.9 0.14.16 BSATTY 21 23:27:39 36.898 113.8206 6.4 -1.08OL-1 .606L 6.7 123 , CI.2.57,,, 2.6 26.6 0.19,16 BEATTY,' 24 22:37:37 36.888 116.813 0.4 8.7 123 AC! 2.64 2.7 19.5 6.12 15 BEATTY 25 22:22: 8 36.898 116.818 6.4 -1.6081 0.7, 122 DC1 2.38 2.40, 2.04 2.5 20.4 0.26 16 BSATTY 26 18:13:14 36.360 114.927 1.2 -1.028L 1.2 '16a OCI 1.59 ,1.64" 126.4 6.13 7 APEX .5 ,)) iS ++ 1991' LOCAL HYPOCENTER SLLUARY - SCe CHD4ICAL EXPLOSIONS' STAND STAND AZI 000 DEL- IMS IN TIME LATITUDE LONGIIUDE ERROR DEPTH, ERROR GAP 12S M4AGNITUDE ESTIMATES WIN RES. 'PH. U.S.G.S. DATE - Scao Mid MLh MLv Mec (101) (SEC),- QUADRANGLE (UTC) (DEG. N) (DEG. w) H(KM) (KW) Z(KM) (DEG) .20.5 6.18 17 BEATTY 8 36.888 116.826 6.5 -1.80801 0.9 127 DC! 2.61 2.7 JUN 26 22:27: 'ACI-2.72 2.5 19.5 0.12 IS BEATTY 27 22:50:38 36.891 116.811 0.4 -1 .800L 6.8 122 36.897 116.820 0.4 -I .00OL 6.7 123 DCI 2.63 2.6 29.6 0.19'18 BEATTY JUL I 22:29:39 19.9 6.15 16 BEATTY ,2 22:21:25 36.896 116.813 6.4 -I. iSBL 6.7 121 ACI 2.38 1.47 2.6 36.896 116.827 0.6 6.9 121 SC!'2.46 "'' 2.5 '28.6 9.20615 BATTY 3 26:53:57 -I I0O,1 .6 ACI'2.24 '1.62 2.3 22.5 6.14"12-8EATTY 8 23:11:13 36.886 116.813 0.5 -78 -1. 62pe -0.69P8 2.01 '1.86 -2.0 •22.7 0.16 13 BSATTY 9 22:24:25 36.892 116.587 6.5 0.9 9CI 2.65 6.4 6.6 "124 BCI 2.70 1.78 .2.7 29.4 0.17-16 BCATTY 16 22:29:43 36.894 116.821 -1.806L 36.893 116.810 0.5 0.7 84 DC! 2.12 2.28 1.84 2.1 19.3 0.18,19 SCATTY 12 22:59:44 2.6 20.4 0.17 16 BSATTY 22:28:41 36.892 ,116.821 6.4 -1.60OL 6.7 124 DCI 2.54 13 1.40 2.7 19.8 0.14 15 BSATTY. 15 22:27:20 36.888 '116.817 0.5 -1.660L 0.9 "125 ,ACI'2.'47 16 22:23: 7 36.890 116.822 6.5 -1.660L 6.8 125 &ACI'2.61 2.30 1.47 1.8 -26.3 0:15 13 BSATTY 38.895, 116.815 6.4 -1.068L 6.8 .122 AC1 2.66 2.5 '28.600.13'15 BEATTY 17 22:21:49 -I .MOL 36.894 116.813 6.3 -1.008L 0.7 122 ,AC! 2.54 2.04 2.5 19.8 6.09 13 BEATTY 18 23: 2:43 1.39 1.96 2.6 '20.7 0.16 15 BEATTY 19 '22:36:16 35.896 115.823 0.4 -1 .6661 0.6 124 fnCI 2.38 38.898 115.821 6.5 -1.0001. 0.7 123 DCI 2.53 2.6 29.6 0.22 16 BEATTY 22 22:42:43 2.5 36.898 A116.819 824 0.6 "122 ,ACI 2.4 1.8.8 26.5 0.14 14 BEATTY 23 22:38:40 -1. 6601 ,1.6 '110 aCt 2.17 2.5 20.6 6.21 24 BEATTY 24 22:54:47 36.893 116.817 6.5 36.895 116.811 6.4 -I-1.0001 .MQL 60.9 '121 BC! 2.56 1.83 2.6 19.7 6.16 14 BEATTY • ,, % 25 23:38:15 DCI 2.47 2.6a 1.52 2.6 26.4 0.16 14 BEATTY r 26 23:43:45 36.894 116.820 0.5 -1.008L 0.8 124 9.5 ,122 ACI'2.59 2.5 19.7 6.15 15 BSATTY 0% 34 0:26:12 36.892 116.814 0.5 4:- 1168.26 0.3 0.6 124 ACI 2.54 2.0" 2.6 29.2 6.12 14 BEATTY 3. 23: 2:47 36.892 -1 .659L 61.9 36.897 116.11 6.5 126 DCt 2.28 2.6 19.9 6.1715 BEATTY 31 23:32:47 116,821 "-1.0406L 6.5 126 ACt1.682 2 15 1.65 1.6 26.6 O.1016'6EATTY AUG 2 22: 7:47 36.886 0.3 i. -! .OO01 1.67 2.5 20.2 0.13'16 BSATTY 5 23:28:56 36.892 116.820 0.4 0.7 124 ACI 2.46 116.814 0.4 6.8 122 ,ACI 2.47 1.98 2.5 19.7 0.14,15 BSATTY 7 22:26:33 36.891 '-1..50L 6.7 9 1 36.897 116.818 6.4 122 BC! 2.59 ,2.5 20.3 0.17'17 BSATTY 0: 8: '-1 .000L 6.7 6.9 26.5 0.13 13 BSATTY 9 21:49:47 36.898 116.819 0.4 122 ACi 1.59 1.09 1.46 26.1-6.12A18 BATTY 12 22:29:21 36.891 116.818 0.2 '8.4 124 ACI 2.40 1.95 2.6 6.5 0.9 125 '26.2,6.18,16 BSATTY 13 22:18a15 118.822 DCI-2.09 2.26 1.66 2.0 8.5 SAG 10 SPRINGOALE 14 15:59:52 :37.874 116.758 8.4 6.45P9 ,0.6 133 ASI 1.04 6.70 36.891 AC! 2.57 1.69 12.5 19.9 0.10 19 SCATTY 14 22:31: 3 116.817 6.3 0.4 123 2.43 37.697 116.003 1.0 149 AC! 1.27 0.45 6.82 21.2 0."9 8 YUCCA FLAT 15 16:10:35 2.6 26.1 0.14 18 BSATTY 15 22:17:12 36.891 116.820 0.4 "-1.0608L 6.6 124 AC! 2.53 1.89 136.894 116.816 0.4 -1.0068L 8.7 123 DCI 2.85 2.28 1.57 1.9 26.0,0.15 17 BSATTY 16 22:45:18 o.5 20 6:29:56 36.891 116.812 -1.80e0 6.8 122 DC! 2.69 2.6 19.6 0.15 1 BSATTY BSATTY 20 23: 9:52 36.888 116.822 0.7 -1.608L 1.2 126 SCi 2.03 2.29 1.62 2.1 '20.2 6.23 17 22:28: 2 36.895 116.809 0.6 -1.608L 1.7 126 SCI 2.47 2.6 19.6 0.22 15 BSATTY 21 AC! 2.5 26.1,6.15 16 BSATTY 22 23:13:55 36.894 116.817 0.4 -1 .00L 0.6 123 2.46 23 22:11:29 36.894 116.824 0.4 -1.906L 6.6 125 DCI 2.13 2.26 1.77 2.6 26.7 0.15 18 BSATTY 79 DCI 2.12 2.29 1.94 1.7 19.6 0.19 20 BSATTY 26 22:28:24 36.893 '116.810 '6.6 1.4 36.890 116.826 0.5 -1.0OL,,1l.081. 0.8 126 DC! 2.43 ' 1.85 2.5 20.5 6.18 16 BSATTY"' 27 22:22:15 t 116.812 0.4 -1.608L 0.7, ,122 DC! 1.90 1.98 1.48 .1.8 19.6 0.15 19 BSATTY 28 22:23:53 36.892 .'" 27.1 0.14 6 APEX 29 18:17:17 36.365 114.913 1.8 -2.028L1 1.9 '179 CI 1.24 125 C--i 1991 LOCAL HYPOCXNTER SLL4ARY - SCS CHOEICAL EXPLOSIONS STkO STAND AZ! '0OO0 DATE -TIE', LATWITUOE LOc*!TUOE ERROR DEPTH ERROR CAP 12S MAGNITUOE ESTIMATES U!N RrIES. P. I (UTC) MLh MLv ULi U.S"C.S. ' (DEG. N) (DEC. W) H(KM) ,(KM) Z(Ku) (DEG) Wca Md (Ku) (SEC), OQUADRANLE ::~~•0.8 AUG 29 22:28:55 3i. 895 116.811 0.4 121 'AC! 1.51 2.20 1.61 1.8 19.7 6.14, 114.899 15 BEATTY 30 -18: 8:46 36.376 1.9 -1.258L 1.2 224 001 1.54 1.29 1.49 27.5 0.09 6 DRY LAKE WV 30 ,23:53:55 36.893 '116.889 8.5 --1.808L 0.9 121 BC1 2.60 2.6 19.4 6.16:15 BEATTY SEP 2 ,18:39:51 36.915 118.862 6.5 13.98,8 1.3 129 AS! 1.35 1.49 6.92 17.1 0.13 19 BEATTY 3 '22:2e:55 ,'36.895 116.822 6.5 "-1.808L 0.8 12A BCI 2.02 2.19 1.69 2.6 20.5'0.16 17 BEATTY 4 23:32:17 :36.893 116.819 0.4 -1.881. 0.5 ,124 AC! 2.41 20.2 8.13'17 BEATTY '.57 1.72 23: 9:31 '36.894 S118.826 6.04 -4.008L 0.7 123 ACI 2.04 2.31 20.3 0.14115 BSATTY 6 22:43:16 36.893 116.827 6.4 -1.600L 6.7 126 BC! 2.48 1.82 2.5 20.8 6.17 17 BEATTY 18:48:26 '36.915 l16..864 0.5 13.53P8 2.8 '129 '58!1ý1.24 1.49 0.85 17.6 6.13 17 BEATTY 9 23: 7:27 36.893 116.821 6.4 -t.OSIL 0.7 124 BCI'2.31 2.58 '1.95 2.5 26.3 6.17.18 BRATTY '10 22:21:28 36.896 :116.836 6.5 -1.0081 0.8 128 OC! 2.34 2.48 2.5 26.9 0.19:20 BEATTY 11 22:33:17 36.895 ,116.816 8.4 -168 .6 122 AC! 2.15 2.43 1.ba 2.6 20;2 0.13 16 BEATTY 12 22:16:68 36.893 116.824 0.6 -1 .6081 3.7 125 9C! 2.23 2.25 '1.72 2.6 28.6 8.15'15 BEATTY 13 22:27:20 36.895 116.811 0.5 -1.6081 0.8 121 9C! 2.27 1.99 2.5 19.8 0.16 16 SCATTY "16 120:34:39 '36.916 116.857 1.6 16.81PS 5.2 172 CCI 1.22 1.12 6.47 17.5 e01412 BEATTY 22:29:41 '36.592 116.818 0.4 -1.6081 0.7 123 AC! 2.50 :1;83 '2.6 26.1 0.15'16 BSATTY '17 '22:23: 2 36.891 '6.6 -1.008L 1.0 126 '"CI 2.28 .1.72 2.5 20.760.20'16 •, 18 +116.616116.827 6e.4 BEATTY :22:33: 3 36.890 -1.808L 6.9 124 "AC! 2.54 '1.96 2.6 .19.8 0.14'17 BEATTY "19 21:56:42 36900 116. 815 8.3 -'I-OWL 6.7 126 AC! 2.34 1.83 2.5 20.3 6.09 14 BSATTY 26 3.4 223 CO! 1.46 '*26 18:48:49 36.383 114.910 -1:570L 1.4 1.31 1.44 26.2 0.12 6 DRY LAKE W 22:45: 1 36.894 116.869 6.8 -1.W08L 0.9 126 OC! 2.50 1.86 .2.5 129 DOI 1.31 19.5 0.19 17 BSATTY 21 '18: 9:36 36.913 116.862 9.5 12.6"P9 2.2 1.46 6.72 ' 17.2 0.11 14"BEATTY 23 22:23: 3 "36.892 116 .816 6.4 -1.608L 0.6 123 'ACT 2.53 '1.96 '2.5 19.9 24 0.12 17 BSATTY 22:18:16 '36.897 116.815 0.5 -1.OWL '1.6 121 BCT 2.96 2.32 1.81 '1.8 20.1 6.17 17 BSATTY 25 '22:47: 3 36.894 116 814 6.5 -1.603L 1.2 122 AC! 2.46 2.6 19.9 26 0.14:16 BSATTY 23: 7:38 36.895 116.516 6.3 -1 .68L 6.7 123 AC! 2.29 2.5 2327 20.2 0.13 15 BSATTY 22:43:353 36.898 116.a22 6.4 -1 .09L 6.6 ,123 8CI 2.30 1.90 2.5 20.8 0.16 16 BSATTY 30 22:5a:31 36.889 116.820 6.4 -1.6081 0.7 125 BC!I 2.39 1.86 OCT 1 23:11:44 36.901 2.6 20;8 0.16 16 BSATTY 2 6.5 -1.6081 0.9 121 OC! 2.15 2.30 1.75 1.9 26.7 8:17 15 BEATTY '2 22:56:27 36.894 116.821 6.5 -1.866L 0.8 124 9C! 2.19 2.28 1.77 2.6 20.4-0.21 20'BEATTY 4 23:49: 5 36.898 118.819 8.3 -1.608L 0.5 124 AC! 2.32 1.84 2.5 '20.0 0.13 19 BSATTY 5 22:48: 4 36.886 116 .815 6.4 -1.8813 0.7 124 BCi 2.42 1.70 2.5 19.5 0.17 17 SCATTY 27 .21:55:8 36.891 116.817 6.5 -1.6691 1.1 123 AC! 2.27 1.75 .2.1 20.0 0.15 13 BSATTY 'I '9 22:31:46 '36.895 116.818 6.4 -1.0001. .7 121 AC! 2.54 1.91 2.6 19.960.11 15 BSATTY 0:21:33 36.897 6.4 *.1 .669L 6.6 122 AC! 2.12 2.28 1.61 1.8 26.3 0.12 15 BSATTY '2 22:44:18 '36.890 116.818 6.4 -1.1881 6.6 124 AC! 2.48 1.96 2.6 20.6 6.13 22 BEATTY 16 11 22:26: 6 36.891 ,116.822 6.5 -1.081L 6.9 125 BCI 2.50 1.93 2.6 26.3 0.20 16 BSATTY 14 21:54: 9, 36.889 116.618 6.6 -1.008L 6.9, 124 BCI 2.41 1.66 2.5 19.9 0.19 17 BSATTY 15" 22:41:47''36.889 116.810 6.4 -I.eO6L, 0.6 122 AC! 2.54 '2.16 2.7k' 19.3 0.13 16 BSATTY' 16 22:57: 8 36.893 116.818 6.4 -1.68L 0.6 123 AC! 2.35 ",'1.79 2.6 20.1 0.13 17 BSATTY 16 18:14:40 36.414 114.840 7.1 1.388L 30.8 242 DO! 1.39 1.53 30.5L6.23 6 DRY LAKE 22:55:16 36.891 116.829 6.8 -1.081. 1.4 127 BC! 2.24 2.38 1.68 2.5 26.8 6.22 14 BCATTY 17 23:50: 8 35.896 116.815 6.3 -1.608L 6.7 123 AC! 2.36 2.38 1.68 2.7 19.7 6.12 18 BSATTY 18 22:43:41 36.898 116.813 814 -1.008L 1.6 120 AC! 2.31 2.46 1.84 2.5 26.1 6.16 14 BCATTY CHEMICAL EXPLOSIONS 1991 LOCAL HYPOCENTER SUMMARY -G A + STAND STAND AZI DEL- RMS : ON DATE - TIME' LATITUDE LONGIIUOE DEPTH ERRO GAP 12S A•NITUDC ESTIMATES ,UMN RES. P1H. U.S.G.S. H(KM) Md MLh ML•v MLc (KW) (SEC) OJADRANGLE (UTC) (DEC. H) (DEG. W) (KU) Z(UO) (DEG) Mcea 7'. OCT 22 23: 9:31 36.892 116.816 6.4 -1 .808L 0.9 123 AC! 2.39 1 . 75 2.6 19.9 0.11 16 SEATTY 23 22:32:50 36.691 116.821 6.4 6.7 125 SCI 2.11 2.56 1. 72 2.6 20.2 0.16 IS BSATTY 24 22:48:32 36.892 116.817 6.3 -1.608L 6.6 123 AC! 2.27 2.53 1.1W5" 2.6 20.6 0.11 15 BSATTY W8 25 22:15:32 36.898 116.817. 6.5 -1.000l 0.9 122 ACI 2.31 2.52 1.1 2.6 26.4 0.14 16 BEATTY 29. 0:23:18 36.8911 116.812 6.4 1.2 122 ACI 2.55 2.54 1.192, 2.4 19.5 0.10,12 SEATTY, 29 23:49:41 36.895 116.815 6.5 -1.OOSL 0.9 122, OCI 2.49 2.5 20.6 0.15 14 SEATTY + 0.4' -I.38L 6.7 122 AC! 2.11 2.37 1. 75 1.9 20.6 0.14 17 BSATTY 0:38:435 356.894' 116.816 91 NOY 1 0:22:54 36.892 6.4 0..ea L 6.7 122 ACI 2.60 1.1 2.6 19.7 0.14 17 BEATTY 2. 0:23: 8 36.891 116.818 6.3 -1.608L-l.H66L 0.6 124 AC! 2.53 2.5 20.6,6.12 18 BEATTY' 72 16 BEATTY. 2 19: 18:60 36.696 116.821 0.4 -I .008L 6.8 123 13CI2.07 2.28 1. 2.7 20.6 0.17 5 1: 3:'8 36.893 6.3 6.5 122, ACI, 2.56 2.1 19.8 6.08,13 BEATTY, 3.1 -I .OOSL 5 19: 6:32 36.383 114.895 -1 .808L 2.7 226 CDI, 1.33 22 27.4 6.12. 6 DRY LAKE Ni 5 23:48:10 56.889 116.818 0.4 -I .8881 0.6 124 ACI 2.45 I.E67 2.6 1g.9 0.13,17QrATTY 6 19:25:29 35.948 115.229 189 AWl 1.67 1.154 42.9 0.66 4 SLOAN 6.7 122 ACI 2.15 2.356 1.68 2.1 19.9 0.12 17 BSATTY 6 23:44: 7 36.895 116. 814 6.4 -1.60061. 7 23:48: 2 36.895 116.817 0.4 6.7 123 AC! 2.52 1. 44 2.5 20.2 6.12,16 SCATTY 26.4 6.16 16 BSATTY 9 22:52: 7 36.896 116.819 6.5 -1.168L 6.9 123 SC! 2.59 2.5 12 6: 2:14 36.890 116.615 0.4 0.8 123 AC! 2.44 1.191 2.6 19.806.13 IS8EATTY 12 23:48:44 36.894 116.815 6.4 6.8 122 AC! 2.66 2.34 1.164 1.71 19.9 6.12j15 SCATTY 6.4 6.9 122 ACI 2.30 1.1 89 2.5 19.6 6.14 15 BEATTY -, 15 23:45:15 36.892 I mw8I -l.008L-1 .18L 14 23:17:11 36.890 116.822 6.5 125 OC! 2.45 2.62 1.187 2.6 20.3 0.26 15 BCATTY 116 .827 -1.6088L 0.9 15 23:46:15 36.887 6.6 -l.e00L-1.106L 128 BCI 2.31 2.57 1. 79 2.5 26.5 6.23 17 BSATTY 18 2.6 20.4 6.19 16 BSATTY 23:56: 8 36.892 116.823 6.5 -1.e6t8L 0.8 125 SC! 2.41 1. 71 19 23:41: 6 36.895 116.816, 0.4 -1.008L 0.7 122 ACI 2.20 2.J6 I. 55 1.9 26.1 0.1186 BEATTY -1.60e0 A' 93, 20 23:14:9 36.890 116.816 6.5 -1. .OeL 0.9 124 SCI 2.43t 2.1 2.5 19.8 6.16 17 BEATTY 116.818 -1. 6891. 88 21 23:51:28 36.889 6.3 0.5 124 AC! 2.34 1.i 2.6 19.9 5.14 17 SCATTY 1 22 23:11:34 36.1895 1168.11 0.3 -I .678L 8.74' 121, AC! 2.49 2.5. 19.7 6.14,15 BCATTY' 116.828 SC! 1.! 2.6 26.9 0.22,16 SEATTY, V. 26 0:10: 4 36.897 6.6 0.91 124 2.23 2.22 7- 116.811 -1. .OBL 61, 2.5 19.4 0.13.16 BCATTY 26 23:46:26 36.890 6.4 -l. 0el. 0.7. 122, ACI.2.56 2.50 .116 27 18:59:41 356.367 114.925 1.8 -1.1003L 1.7 178 DC! 1.65 1.86 .1 26.1 $.111 6CAME.. 27 23:24: 3 36.892 116.818 6.4 -I .3791 6.7 124 AC! 2.33 1. 67 2.6 26.1 6.13 16 SEATTY, 6.3 6.5 128 AC! 2.28 2.6! 1. 72 2.6 26.2 0.69 13 BCATTY DEC 1 22:57-:52 36.884 116.826 73 3 6: 1:57 36.888 116.825 6.6 1.6 126 BCI;2.34 2.66 1. 2.4 26.2 6.26 14 BCATTY 3, 23:10:54 36.892 116.825 6.4 -I.108L 6.6 125 9CI 2.25 .196 2'6 26.4 6.16-16 BCATTY 4 23:43:16 36.886 116.824 158 AD! 20.1 6.01 4 SCATTY -1, 1651 5 23: 6:19 36.891 116.828 e.7 1.6 127 BCI 2.43 .191 2.5 20.8 6.26 14 BEATTY -1.108L 6 23:40:22 36.896 116.825 6.5 0.8 125 DCI 2.26 2.5e 1.1 2.6 26.8 6.17 15 SCATTY 36.893 116.828 6.5 -1. 168L 0.8 126 SC! 1.94 2.03 1. 51 1.8 26.9 0.17 15 BCATTY 9 23:45: 2 -1.t1081 16 23:40:16 356.893 116.811 0.4 1.6 79 ACI 2.49 2.2 19.6 0.13 22 BCATTY 11. 816 6.3 -1 .6081 0.6 123 ACI-2.23 1.,as 2.6 19.9 6.14 15 BCATTY 11 23:46:14 36.891 -1.168L 12 23:40:10 36.891 116.813 6.3 0.6 122 AC! 2.37 2.5 19.6 6.11 16 BCATTY 1 C> ;7.. Appendix C Nuclear device tests and low-frequency shallow seismicity in the NTS, 1991 Hypocenter data for announced Nevada, Test Site underground nuclear device tests that were detonated in 1991 are listed in table C1, as they are reported to the National Earthquake Informa tion Center (NEIC) by the Department of Energy. Magnitude estimates are provided by Berkeley "Sisrmographic Laboratory3(BRK) or by-thiNEIC.'Groundvibr-ation-from most NTS nuclear deto nations saturates all or most SGBSN stations for several tens of seconds; thus, only initial P-wave arrival times can be reliably scaled from SGBSN seismograms of those tests. Relatively high levels of seismicity are regularly recorded in the vicinity of many NTS nuclear explosions by SGBSN stations for periods ranging from hours to days following the tests. The seismicity listed in Appendix C, table C2 (located events) and Table C3 (unlocated events), consists of events having characteristically lower-frequency P-wave coda and S-wave coda than the vast majority of earthquakes in the 'SB. Mast low-frequency Iocal earthquakes, which we designate "LFE's,'; are associated in time and space with nuclear-device testing at Pabute Mesa, Yucca Flat, and in a few instances, at Rainier Mesa. Some of these events may be identified as the collapse of a given test. LFE seismicity is usually recorded by .2BS.' stations at high levels until the time of the cavity collapse, after which the LFE seismicity level abruptly and sharply diminishes. Good examples of this pattern' may be seen in table C3, for the events following the April 1991 tests I BEXAR'and MONTELLO at Pahute Mesa. In some instances, a heightened level of LFE seismicity continues for days to'weeks following the collapse. This pattern was observed for :the Pahute Mesa test LOCKNEY,(Harmsen and others, 1991). Dctectable LFEs rarely continue at a high level for more than a few hours following nuclear-device tests (or collapses, if any) at Yucca Flat or at Rainier Mesa. For example, relitively high levels were detected for about 4 hours following the Yucca Flat test LUBBOCK (and its cavity collapse) in October 1991 (see table'C3). Figure C1 is a plot of nuclear-device test epicenters listed in table C1 and of LFE epicenters listed in !Table C2. Figure* C2 displays several 1SGBSN seismograms for a pre-collapse LFE fron BEXAR (note the high level of pre-P vibratin' aýt the nearest station to the hyjocenter, EPM). A few LFE hypocenters outside the NTS are included in table C2. Most such LFE hypocenters from this and previous SGBSN catalogs are probably ineccurate due to low signal-to-noise ratios at near-source stations at che time of presumed P-wave onsets. However, it is possible that some LFE's occur at relatively great distances from the nearest underground nuclear test (15 km?, Harrmsen and others, 1991). These events may be indicators' 6f slow straixi diffusion in shallow crustal rock at the NTS. The relative abundance of LFE's at random times in June and July 1991 provides evidence of ongoing shallow seismic strain release at northern NTS.'Whether this "delayed" LFE seismicity is more closely-associated with nuclear explosions or with temporal -iariations in thE regional shallow crust strain field is, in my.opinion,,not known. Table C1. Announced nuclear-device tests at Nevada Test Site in calendar year 1991. YRMODA HR MN SEC.IML or Mb Latitude Longitude Depth - NAME ..... ". ... UTC 1 SRC'! f 'N -W (km) _; _,__ _ _ _ 910308 , 21 02 45.08 4.6 BRK 37.1044 116.0740 -0.95 COSO BRONZE/GRAY/SILVER 910404 . 19 00 00.00 5.4 BRK 37.2961 1i16.3129' -1.54' ` , BEXAR 910416 15 30 00.07 5.4'BRK 37.2454 116.4416: 1.39§' " "'-,MONTELLO 910815 16 00 00.00 4.0 BRK 37.0873 116.0018 -0.81- . FLOYDADA 910914 19 00 00.0 5.5 NEIC 37.2256 116.4281 -1.32 HOYA 910919 16 30 00.0 4.0 NEIC 37.2357 116.1664 -1.68 DISTANT ZENITH 911018 19 12 00.00 5.1 BRK 37.0634 116.0453 -0.78 LUBBOCK 911128 18 35 0.073 4.6 BRK 37.0965 116.0696 -0.82 BRISTOL 67 - 751 - r . '- -'& - -.. ,t: -. T 'S C 1991, 37.55" ý I -I .1 7 $ 36.5 117 115.8 I0 I10 f 120 - 30 km . £-L- "•"j"iUL YM-Yucca IMtn. 0 CITY OR TOWN NTS-Nevada Test,Site' L LFE epicenter O UNE enicenter Figure CI; Epcner o nnone NT ular device tests detonated during the calendar ,ear 1991 are shown in map view (octogon symbols), along with some nuclear-testing.induced actl'vlty ('V symbols). Location unceriiainty of tie "Ls" is high, due to low sign.l-to-noise ratios in the seismograms of SGBSN instiuments t!hat record the collapses. I 68 Y' ý' -v-. --e, 4.-, rd.., - 1 I Figure C2.-Seismogra-ms (rojn;SeraflSGBSN stat:ons ror :wo or' more induced low-frequency events occurring about 5 hrs after the Silent Canyol' nuclear devic-e test BEXAR (1991-04-04). The nearest SGBSN station, EPM, records almost continuous ground vibration for'several hours following larger Silent Canyon Caldera tests-. 69 ) ft - -. - TADLE C2. 1991 -LOCAL HYPOCENTER SVAWARY - 548 LOO-FREQUENCy PHEOMC*ENA STAND STAND AZI DEL- •JS IN DATE - TIME LATITUDE LONGITUOE ERROR DEPTH ERROR GAP 12S MAGNITUDE ESTIMATES uRN RES. (DEG. N) (DEC. P1H.U.S.G.S. (UTC) W) H(KW) (KM) Z(KM) (DEG) MCa Md ULh MILy UlLa (M) (SEc) QUADRANGLE FEB 7 8:25:29 37.265 116.490 0.6 9.28 1.0 133 Bel 1.81 1.54 1.5 13.6 8.17 18 SILENT 7 17:34:15 37.414 116.467 3.6 BUTTE 22.62 1.5. 282, CO..I.56 2.09 0.97 20.5 0.12 7 GOLD FLAT EAST I 7 21:52:46 ,37.343 116.252 2.8 14.27 3.5 299 Col 1.11 1.86 6.89 1.5 14.9 0.25 8 DEAD 10 16: 1:21 37.321 116.475 HORSE FLAT 2.6 14.14 2.5 232 CDI 1.58 2.33 1.37 1.8 15.6 0.13 8 SILENT BUTTE WAR 6 17:57:57 37.330 116.336 2.8 12.72 1.2. 278 CDI 1.26 1.91- 6.90 1.6 11.5 8.15 8 8 21:28:13 37.104 116.077 DEAD -ORSE FLAT' 1.0 19.23 1.7 148 BCI 1.45 1.22 11.8 0.16 11 YUCCA FLAT 8 21:39:19 37.126 115.960 1.5 -1.67 1.2 222 501 2.71 2.04 2.4 9.5 6.22 13 JANGLE RIDGE S",(COSO'COLLAPSE e) APR 5 0: 1:39 37.280 116.3e6 2.0 1.79 2.9 197 801 1.56 6.5 6.25 11 DEAD WORSE FLAT 1 JUN 4 4:25:14 37.258 116.4356 0.3 "-4.76 8.3 123 ABI 1.69 1.46 2.3 9.4 6.68 13 SILENT BUTTE AUG 15 16:12:15 37.088 115.941 0.8 1.66 1.7 ,37.082 128 AC! 1.86 1.47 1.31 14.0 0.12 8 PAIUTE RIDGE 15 18:16:45 116.014 e.7 0.26 1.4 75 1.64 1.74 OCI 1.47 2.1 ,13.0 0.22 23 YUCCA FLAT, 15 16:17:18 37.e85 (FLOWDAOA COLLAPSE9) 115.918 1.4 -1.6. 2.5 251 1.80 1.27 1.54 2.1 15.4 0.26 11 PAIUTE RIDGE (FLOMADA COLLAPSE.) 20 18:26:43 37.270 116.486 6.5 5.36 3.1 86 ,CI 2.19 1.93 1.97 2.6 13.9 6.17 23 SILENT BUTTE SEP 14 20: 4:43 37.227 116.422 8.3 B81 2.93 2.9 46 IDCBOII 2.74 J.24 2.95 2.5 26.6 0.15 39 SCRUGHAM PEA( 17 14:32:21 37.228 116.418 0.5 "-4.53 6.4 113 2.42 1.66 2.4 7.4 0.12 26 - 2:39:11 37.225 AB! 13 SCRUGHAM PEAK 116.413 6.9 2.81 1.8. 86 Ba' 1.89 1.53 2.0 6.9 6.18 15 SCRUGHAM 26., 2:39:11 37.225 116.413 6.9 PEAK 2.81 1.8 86 Sol 1.89 1.53 2.0 6.9 6.18 15 SCRUGt4A PEAK OCT 18 19:59:58 37.043 115.997 1.9 9.34 3.0 222 0.98 18 20: 5:25 37.062 901 17.4 0.22 12 PAIUTE RIDGE 116.044 1.0 -1.85 1.4 146 BCI 1.35 1.10 1.19 " 14.9 6.28 17 YUCCA FLAT NOV 5 19:49:39 37.244 116.439 6.6 4.96 1.6 171 AC I 1.87 2.36 1.25 1.5 9.5 0.16 11 SCRU•HAM PEAK * Nuclear-device test collapse times provided by S. R. Taylor. Los Alomos National Laboratory (1991. written comun.). I.5 - .,, -- r - TABLE C3. 1991 SGC LO*-FREOUENCY EVENTS WITHOUT HYPOCENTER DETERMINATIONS MONTH DA HR:lN DA HR:MN DA HR:MN DA HR:MN DA HR:MN DA HR:IMN DA HR:MN JANUARY 02 I1:17 i4 14:42 0e420:0 04,20:14 _0 19:19 . "FEBRUARY 16 13:46 20:44 423 . - MAR01 . ALL! LOW-MFEQUUDCY EVENTS'IN MAR-HAVE H CfTERS (Uoo table C2). AAPRIL"'' '419:16 04 19:23 e4 19.25 04 19:29;-04.19:32 04,19:45 04 19:47 04 19:41 .04 19:54' 04'20:01 04 20:63 04'20:e6 64 20:10 04 20:12. 04 20:15 -04 20:21 04 20:28 04 20:42 '04 20:47 '04 20:54 -'04'20:56 - "4 21:00 e4 21:09 04 21:27,04 21:31 ý04 21:46 04 22:00 :04 22:02-" - 04 22:34 04 22:37 84 22:41- 04 22:53 04 23:02 04 23:3e 04 23:33 04 23:40 0e423:42 0e423:48 04.23:50 ý04 23:52 -'05 00:0 0e5e0:04 0500:11 0500:12 05 0e:14 05 e:19 05,08:23 05 00:28 05 e9:33 05 00:38 -05 00:41* 05 02:56 04:2925 0900:22 e9 ,4:25, 09 06:29 eg 96:31 13 17:64 1317:18-'16-15:38- 16 15:41' 16 15:43 18 15:48 16 15:49 .16 15:52 16 15:54 16.15:56 .16 15:5a8 16 15:59 16 16:62 ... .'• IS16 16:05 16 16:e9 16 16:19 16 16:12 '6S 18-16 16 16:20 16 16:23 18 16:24 16 16:26-, 16 16:30 .16 16:33 - 16 16:35 16 16:41 -16 16:44 16 16:47' 1 16:54 16 16:57 ý16 17:6e 16 17:03 18 17:le.-,1e 17:13 16 17:15' 16 17:20 16 17:22 16 17:24 lb 17:29 16 17:44 18 17:45 16.17:51 16 17:55 16 17:5181 16 16:01 16 16:02 16 16:04 16 18:08 S118:13'e16 18:18 16 18:17 16 16:22 16 10:23 16 18:25 '16 16:27 16 '18:51-" 16'18:54 18 18:44 16 18:47 16'18:48 16 18:58 16 16:52 16 18:54 16 18:56 16 1g:04 16 19:06 16 19:15 16 19:17- 16 19:21 16 19:27. 16 19:31 18 19:38..,, .MAY '-29 2e:32 ..... " " " ' J'UN.EJU-E.. 01 ee:17 e7 20:14 -14 r.2:16 16 14:14 , 17 00:17 17 04:29, 18 09:32 ,18 09:53 18 19:36 '25 01:54 -: - - * JULY' e4"0:23 -e6 19:52' e9 01:20 12 20:3 1 .13'12:04 13 14:19 13 18:38 15 21:17 14,18:23 14 2e:35 14 22:33 16 68:13 '16 03:23 16 04:14 "1804:24 16 e4:31 18, e4:47 18 04:53 18 12:28 23 00:11, 28i22:25 S'AUUST 01 12:23 0l 21:05.05 06:08m 15 16:10 15 16:11 ' 15 16:16- 19.15:25' * - '28 15:26' 2b 17:31 25 e4:43 26 10:00 28 15:04 ' SEPTDABER 02 e0:14 12 85:355 14 19:06 14 1g:07, 14 19:009 14 19:11 14 19:13 -. '14 19:15 14 19:20' 14 19:24 14 19:25 14 19:29, 14 19:31, .14 19:32 . - 14 19:34 .14 19:38 14 19:43 .14-19:46 14 19:4a"14 19:5e '14 19:56 14 -19:58,, 14 19:59 14 20:e4 14 20:12 -14 2e:14 14 20:21- 14 20:22 - 14 20:26 14 20:29* 19 21:38 19 21:43 20 02:39 23 1e:47 26.16:5., -,.27 00:57 !27 16:47' ° - '' " OCTOBER"" 0106020:35 e504:40 08 10:49 .16,11:29 16-1g:18. 16 19:41: '15l S. 19:43 ;18 19:49118 19:59 18 20:e5'1820:34-18 21:14 18 21:28 18 21:34 18 21:43 18 21:51 18 21:53 18 22:e2 18 22:06 16 22:27 18 22:36 1 22:40 16 22:46 18 22:47, 18 22:59 18 23:e0 18 23:01 16 23:03 18 23:e56 18 23:12816 23:19: NOVD8ER e3 03:37 e6 23:33 13 ee:e5 26 18:356 .26 18:59 26 19:09 26 19:25 , 26 19:30' .26 19:34t'26 20:07j, 26:20:14 26 20:15 26 20:51 26 21:2e _'.'26 21:26' 26 21:40-26 21:49--26-21:51 26 21:58 26 22:23 26 22:25 26 22:32 26 22:34 26 22:47 26 22:54 26 22:58 26 23:01 26 23:13 26 23:24 26 23:29 26 23:35 26 23:37 28 23:38 26 23:42 26 23:44 DECEMBER NOhNE ' -. ' . * Collapse time Is• ator shortly followlng th slow -frequency event time (S. R. Taylor. Los Alamos National Laboratory. 1991. written commun.). ' 71 Appendix D Southern Great Basin earthquake focal mechanisms for 1991 The focal mechanisms of Appendix D were obtained by. selecting the best-fitting solution(s) from the application of the cormputer progriln "FOCMEC* (Snoke and others, 1984) to the ray data generated by HYPO71, and in some instances, to amplitude'daia. We plot data on, the lower focal hemisphere using the equal-area projection (Lee and Stewart 1979).The -polarities, and symbols represent thir positions represent the points where the HYPO71-determned raypaths intersect the focal hemisphere; The darkened circles represent impulsive compressional arrivals, the + symbols represent emergent compressionals, the ope'ri circles represent impulsive dilitationals, the - symbols rep'resent emergent dilatationals, "nd the x symbols represent indeter minate or nodal readings. The.+ symbol at the center of each mechanism is not a compression; it is a point of reference for readers who man wish to search for alternative solutions using a Schmidt (equal area) net. SGBSN station names are printed adjacent to the first-riotion symbol for many of the solutions presented in Appendix D. Ini the following figures the P and T symbols represent the pressure aid tension axes, resp•ctively. The X and 'Y symbols represent ilp ý'ectors for each nodal plane, and B. is the null axis.: Primed P and T sym.'ols are'the'respective vectors for (dashed) solu'tions.when alternate they are presented. Some mechanisms from 'previous SGB data reports are composited using data from several events that are clustered in'time and space. Composite solutions are not present in the 1991 data set. - For one mechanism, shown in figure D7, the irformation'contained in P-wave polarities not adequate was to effectively constrain the range of permissible nodal'planes. For this e'arthquake (1991-05-15 20.01 UTC), first motion P- and SV-amplitude data were gathered at station NOP, indicated by 'a large squ'are around its P-polarity' symbol. The observed and theoretical far-field 1oglo(SV/P). ratios and the difference between the logarithms of observed and theoretical ratios are computed for hundreds of potential solutions whose nodal planes cohform tb P-wave first-motion polarities. The preferred nodal planesishowvn in figure D7 corr~espond' to the "optimum* solution, having the minimum theoretical-to-observed ratio difference and no polarity inconsistencies. In general, five or six SV/P ratios-should be computed, but for this earthquake all near-source stations' SV-wave amplitudes were overdriven. Kisal;nger and others (1981 and 1982)!and Roger's and others (1987b)'discuss several assump tions that must be satisfied for the (SV/P),. amplitude ratio'method to be valid. Their comments and obsirvations are included herein by reference. Foi completeAess, the actual formula used to compute the theoretical (SV/P)' amplitude ratio, as cod~d in focmec.for, is explicitly stated (from Kisslinger and others, 1981 and 1982). The formula for the ratio of SV to P wave-displacement amplitude in the far field for elastic'waves leaving a shear dislocation 'point source may be written (sv/P)o = 3Cot \V. 6 - (cot - tanS)sin Atan OsinA + 2siA + csc/cosA tan qbcos A] e -2D where ' ' .'' D = co+,;cosZ ; Ain 1- sini sin Asec2S+nco2sAc ] i :-,+ sinAsin Obcos~bsin A(cot6 - tanS) + sin A(cosý g6 --sina2 sin 2 A). In this formula, V, is the compressional wave velocity at the source, V. is the shear wave re Ilcity, 0 is the takeoff angle of the ray, measured upward from the z-axis, which points downward, 72 9 - V .- 6 is the angle between the fault plane normal and the z axis, A is the rake angle, measured in the fault plane, and A is the source-to-station azimuth. For comparison with theoretical (SV/P)0 , the observed (SV/P). ratios are corrected for propagation effects (Rogers and others, 1987b). It is assumed that the raypaths for the P-wave and S-wave are identical, or, equivalently, that the ratio of V. to V. is constant over the source-to-station raypath.-,-' . i I / 1 1 I 't , I r '' y 4,- 4, 1 * ,- - - I - 5. 5! I- *r " .-< 73 .4. I' I, :;7 'C r 0-- azi plunge P axis 20.24 11.94 LATHROP WELLS NW T axis 288.29 9.18 DATE&-TDME: 910105 8 55 21.84 B axis 181.68 74.87 LAT* 3e.730 LONG: 116.432 X axis 84.52 1.93 DEPMH. kn 7.55 +/- 0.6 MU 1.5 Y ax!, 334.00 15.00 DIIN (km)- 8.5 strike dip rake Soln 1 84.00 75.00 -2.00 Var 2' 84.00 fi4.00 -24.00 Coetranlnt an solution set or nodal planes is Fali- using Pove Var V 87.00 67.00 11.00 pr larItIas: in not op ,r•Jng at th. tI• of' this eo-th1 luod have hel•p• This is the Act•r•ook ar a aQl I se-ls*a. of Yucoa Miounlain. Figure Dl. Focal mechanisms for this earthquake near Fortymile Wash, southwest NTS, January 5, 1991, display mostly strike -lip, right lateral on the North 3350 West nodal plane, and left lateral on the auxiliary nodal plane. The small mechanism in the upper right of this figure (and all other figures of Appendix D) is a copy of the large mechanism's preferred solution, with compressional quadrants darkened, shown here to help the reader identity this mechanism when discussed in the main text of this report. 74 (r L / o-. , -a. * - I .E t % "r - azi plunge P axis 181.73 15.09 T axis 75.39 46.23 INDIAN SPRINGS NW B axis 284.74 33.86 -31.51 19.06 DATE&TD&: 910301 17 24 56.03_ X axis LAT: 36.631 LONG: 115.644 -Y axis 141.00 44.00 i(L23 , -DEPH~k: 111+! 2.5 aLrlke dip rake * DIMDILIN. (km),-(kin) 18.4164- Soln 1 231.00 46.00 27.00 Var 2" 235.00 60.00 35.00 37.00 is a roreshock to a series Var 2" 237.00 54.00 This earthquoas k ? Indian Spne. Ny. vrrom Junar to July. n at *i P 1 @tol • oaallpOoI• oonelltwancxJ occus at stOtion ., , Springs. Nevada, foreshock" of March 1. Figure D2. The focal mechanism solutions for this Indian northeast-trending nodal plane, predominantly right-lateral strike slip motion on the 1991, display planes. The sense and predominantly llft.lateral strike slip on the west-northwest-trendingnodal the central'Las'Vegas'Valley fault. All nodal of motion on this plane is opposite that expected for substantial component of thrust. plane s•!ip vectors contain a 75 V V .. , .... ý.N-. 'f i: { I I r,,. t i '\X,•.. azi plunge " -~ P axds' 38.58 24.84 T axis 130.55 4.29 LOWER PAHRANAGAT LAKE SW B axis 229.78 64.94 910310 21 38 47.89 X i 87.31 20.35 "DATE&TUM: 352.00 14.00 LUT: ' 37.115 LONG: 115.227 Y axi3 4.1 DEPT1,kmn: 6.11 +/- 0.6 ILL rake Soln 1 82.00 78.00 -21.00 DILIN (kmn)- 8.8 -11.80 S. 'Var Z* 83.30 73.70 -29.15 Z' 83.06 82.56 Th. ar-thiks ro whichi this rool .. Va" 0F a eIIalI In the Paor-oWagt Shearo Zone begmiIng on Miarch 10. 1331. Zone mainshock of March Figtre'D3. The focal 'mechanism solutions for this Pahranagat Shear on the north-south trending nodal planes, 10, 1991, display predominantly right lateral strike slip planes. and left lateral strike slip on the east-west trending nodal 76 .4 L.. - - -,...- J Is 1- YT ,TCN IT - TN azi plunge P aids 57.03 39.41 T axis 170.63 25.98 BARE UTN B axds 284.34 39.53 DATE&TIUE: 9 54 21.48 , X axis 120.42 49.34 10312 13 8.00 LAT: 38.939 LONG: 116.594 t Y axis -21.00 "-"'DEPTH. 1m: 5.94+/-,1.9I 0.8 .... sre dip SolII 11.00 82.00 -50.00--rake 11.1 -55.00 SVar 2Z 111.00 82.00 -• nfl rk Fnf The oad ,moe Al r odOal PlWS ah- '_. Var 2 I le 0ou. -14... a ar sIorlutlon. ore seleoted rr-o. r s set.aIIp ,.oet(ro Iher or tieee hon rxw>•lslme.berOI ,N')a I I honhe* Nevada, earthquake at northern Bare Mountain, focal mechanism solutions fr this Figure D4. The alternate solutions, having varying nromrl slip. A large 'number of indicate oblique strike slip of this earthquake is so small. shown. Because the mainitude of reverse slip, are not from this earthquake components solutions are also possible, data and because a wide range of alternate Mt. 0.8, in this report. - comrute average P and T directions ' -- *'~are not used to 77 .1. .4 -.. . * - S * .,, , I -E plunge P aris 250.15 44.14 T, axis"- 89.85 44.14 RYAN B aias 350.00 10.00 DATE&TDLE: 910413 16 8 57.86 1 SXaxis 80.00 0.00 LA'T. 38.488 LONG: 118.575 Y axis 170.00 80.00 "DEPTH. kmn: 4.80 +/- 2.9 MU 1.3 DUDII(kin)- 13.4 S- - s~t.rike dip rake Sola 1 260.00 10.00 0.00 41%0.VU 85.00 85.00 RG0SR DESERT. CALIFMIAR4EVADA BORDE Dilatotlonal first motions for, this .cwthquok. are aboaved over a v" wyi do range or *ouroe-to-,tatli oxazmuh. lu.ing the I I Itq or celSAlo ali an Som.C-ho:zontol Cdietoomvent}t vult. The q.8-k^ 'depth or fooue do"e not owtipond to a Asnlinu t.volts#% residualS htcxntet solution. All foool m 1o e'lutlone for.thl hipooente have a mub-horizontel nod•l plane. -. I Figure DS. The' focal mechanism solutions for this Amargosa Desert (Ryan quadrangle, Calif.) earthquake all display a sub-horizontal nodal plane when using the 4.8-km focal depth. However, surface-focus hypocenters have lower average traveltime residuals, and display a much wider variety of possible focal o... chanism solutions. Data from this earthquake are not used to compute average P and T directtuus. in this report. 78 IC...... - I j:R H- •azi plunge LOWER P. GAT-. LAKE Taxis- ", :Pi 121.14 18.01 33.8318.71 LOWrER PAHR&AGAT LAKE B axis 234.96 -50.02 910415 6 53 37.04 X axis' 74.29 .38.35 LAT:DATE&TMLE: - 37.i21 LONG: 115.211 :',' ;..' " Y axis 338.20 -9.60 3.79 +/- 1.3 ML: 3.1 . " strike - dip rake DEPTH, km: soli '66.80•"1 .80.40 -39.00 DILNN(k]m)- 5.7 -33.30 * 'Jar 2' 68.80- '78.70 The kiFjpot For hicoh tlh , Focal i-e sffuu w.eprpie w e in tha .mainwok or I: In the Pao-onat Shear Zonel in AprIl. 1991. Shear Zone earthquake display Figure D6. The local mechanism solutions for this Pahranagat oblique strike slip normal ship. " " Z.-I * "79 M I I, , - 7 (1 cE W azi plunge P axis 181.00 29.93 STOVEPIPE WELLS T axis 89.29 ý'3.08 DATE&TIfLE: 210515 20 1 50.43 B -axis 353.97 '59.88 LAT: 38.;30 LONG: 117.148 X axis 229.09 18.35 DEPTH. = 8.75 +1- 1.2 ILL: 2.8 Y axis 131.00 23.00 DILIN (kzn).ý 11.5 strike dip rake Soln 1 221.00 67.00 -20.00 Var 2 208.90 -35.50 -30.60 Largest earthquake of a series in mid-May 1991., Var 2" 230.10 88.20 9.80 with epicenter about 3 km north of Stovepipe Wells. Calif. Figure D7. The focal mechanisw solutions for this Death Valley earthquake display a wide range of nodal plane dip angles. However, the tension (T) axes of these solutions' all trend - east-west, providing potentially useful information about crustal stresses in the vicinity of Stovepipe Wells, California. 80 - -. A .%4 .1 I E I azi plunge P axii 54.19 37.44 "S.P.IUNGDALE -T axis 314.78 12.08 "SPRINGAL 9-0 0B axis 209.99 49.99 DATE&T=: 910805 14 58 10.12 X axis 99.50 18.37 IAT: 37.103 LONG: 118.998 Y a.l 357.50 35.30 kzL.i :5.31 +-- 1.0 - M- 3.4. 2.DEPTH. rake ~.. N(k•)= 13.8 , - Soam n'87.501 54.705 -20.20 Var 2' "97.70 40.70 -9.40 4 "Constrolnt on the solution set Var 2"" 90.40 77.80 -48.90 I1 f - - ", fa inr'l Fo P wveflratthis Soroobatue maotIon Flat ethquok-tO. •r;SIOp veotorn rea,.y • - -, to ob ique rwo.ol. .trikesl ip. '.-"v ~ , Figure D8. The focal mechanism solýtions for this Sarcobatus Flat, Nevada, earthquake are, for the most part, predominantly strike slip Constraint on the range of nodal plane dip angles is poor. -- r. -1 81 ] ''4 .1 . * .'s-.t ( -E 41 'C azi lunge SPsxas43.688 35.6a 3SPRfl•GDJM" •T axis 145.3e 15.79 B axis 255.04 19.96 DATE&'FWIUF, 910812 22 39 26.84 X axis 100.45 37.20 LONG: 118.958 X a' 0.8045 LATK.*37.192 f 12.70 DEPTH. km. 6.00 +/- 0.7? 3.3 Y axis DMIN (kin)- 21.0 Sol 1 '90.80k dip rake Var 2' 90.70 77.30 -38.30 51.80 -12.30 This Sr obatus Flat earthquake Va-r 2' 90.00 81.40 -59.60 room I NhnIW molutlon wet 1`a77es fr•m predonlanwtiq strike-al oblil fl-Ol slip. The 6 kA fixed depth Is f t u nIuan bof the RMS residual groph UMS - B1.12 seconds) .Ia'nI htude based on .. dill" froa 38 dO LSMand LS2IE station data onlIH:III 'vetioal comaponent data 6.(. *1ipped. Figure D9. The focal mechanism solutions for this Sarcobatus Flat, Nevada, earthquake also display a wide range of nodal plane dip angles. 82 - .. 3. .1 ). - IN azi plunge mm P axis 50.69 29.78 T axIs 285.58 45.16 1LERCURY B a3ri 180.01- 30.03 DATE&TflLE: 910814 8 24 54.48 CX ariX 255.05 8.64 "LAT. -,38.739 LONG: 115.985 - Y axis 359.40 ' 58.50 2 -.. . -' t.rk; dlp DEPTH. kin: -2.GO +/ 1.1.:- .2 _.. .. t i k , i rake18.70 - D1LDM(kin)= 8.7 "Soln'l 89.40 - 31.50 Var 2' 84.90 30.40 8.60 WVar 2" 100.70 - 31.60 36.30 This Frencmaon FltT. HS. earthquake dl IT dual R traovel tIe t',ldual It k Rbeuow " WOaObelio sh~ownat z-2 hen.) and at z at at- just, belo"at e level UMl nrimdI1.l41 sWc. ,.. Thhdilotation at SlRG (azimJth i -- ot-th 13•9 dog. Vast) is questionable. 4. Figure DIO. The focal m-chanism for this Frenchman Flat, NTS, earthquake are predominantly yertical ,strike slip on the shallow-dipping east-west nodal plane, and oblique sl1p on the almost dipping north-south nodal plane. 83 | I ic - r.s.'.; * %'.* .*' +r lam. SSP *BG TM GVN CTSN F.P ais 58.0 2.81- " " ':T aria 321.73 12.29 TDBE*H•B aris 209.49 80.06 - - 9.87 - X axis 102.21 - 9.70i LATDATETM 37.114 910818 LONG: 22118.4428. 59 DEPTH. km- 9.03 +/- 0.5 MU 1.4 Y mIt..-•trik &p,dip ra:0rake DMIN (ki),, 10.2 Soln 1 97.00 82.00 -11.00 "Var V 100.00 40.00 0.00 The r-mmjpoatoe this owlthqa. Var 2" 101.00' - 83.00 19.00 eT te no•thern b o the Timerlountoin Colder-. dIplotj" a RMS travel tiao A"ft." ror depth. ,."O- ng rro 7 to $ kA below .e Iel. "loat focal neohonlor%solutions dippingcw nodal pl•., Ike Ml.rOdoInontlIp on osepliq Figure Dil. The' focal mechanism solutions for this Timber Mountain eathquaice are all predom inantly strike slip. .co*84 .6- . .- 4E - - LU YUT6 '4T UC CDH1 iT'\, i!-i SSITS IN, pmp -BG- N. "P`X LR "i iTCN-! ) WT" ,•i , . • .' l ...... -aml plunge P a&id 59.94 4.81 TO.'--." A2H " T axis 150.05 1.27 "TOPOPAH SPRING N B axis 254.78 85.03 DATE&TLE: 910704 0 22 .11 X axis'105.09- 4.30 LWNG: 116.421 - a- 14.90 2.50I LIT:. 38.997 1.4. Y xis14. dipp rr0 k .DDEPTH. UIN fk,-)- 3 -5.27.67 +1- 0.5 UL• - ~ i e d -, "-- Soln 1 104.90 87.50 -4.30 Vae 2 285.80 76.40 8.50 Thi .tm-t t•,cwell I ocntrained at a . Var 2 278.90 55.20 -3.40 below ea level. The deth '" pB I kA rin the resugnt, %o entel *o t erMuntaInthe mouth Ccldaco, I ex. Focal aean•mA molutlone allstrlre-iI011 Ip. iarthquake are Figure D12. The rocal mechanism solhtions for this Timber Mtn. resurgent dome "all predominantly strike slip. " ". . ." " --- 85 i . )q ' '>-- 6 I I Z! t ! C 000 ai plunge P axis 19.81 4.02 INDIAN SPRINGS NW T axis 110.38 8.82 DATE&TDL: 910712 18 41 30.51 B axis 280.21 80.08 LATM, 38.833 LONG: 115.840, X axis 84.78 9.59 DEPTH. kzr 1.29 +/- 2.0 UL 2.8 Y axis 155.20 2.80 DUIN (icm)- 18.7 -strike, dip rake Soln 1 245.201 87.40 9.80 Var 2' 245.30 88.60 ljpoet.,- I.- this earthquk~e 9.40 lndiw, Spi.lr~s. Nevada. ho lnJp.~ Var 2" 245.15 88.30 9.90 at L k" belw mIlevel M 4 I Ower. Thee.mfwI AeohanIan solutlron haveaone polarltj tnoonseltt"-,rj at statlon HTI. Figure D13. The focal mechamism solutions for this Indian Springs, Nevada, earthquake are very well constrsained. They are stnke slip. The nodal planes do not agree in trend with the major Las Vegas Valley fault, although thu sense of slip on the north-northwest trending plane agrees with that expected on the Las Vegas Valley fault. 86 C 2 - - *t. * ...... V ,. ".s* .v*1 I,',''I. . .. - 'I I , ]M GM_ -.-.M -.azl plunge P • 315.00 75.00 -" CRATER.. "T axis 135.00 15.00 DATE&TDE•: 910805 11 40 -19.9i' .1 axi 315.004 0.00 LAT: 37.180 LONG: 117.414 Y. axi 135.00 60.00 DEPTH. kin 5.71 +/-, 1.0 Mu 3.0 =;, Dial (..m)- 19.3 Soln 1'225.00 30.00 -90.00 - Var 2 49.00 70.00 -79.00 .,io-aru k o r. 12 -eq w is.- . -Var, 2 ' 220.0 0 15.00 - 90 .00 This a -1 u oda r o1= @1111ed v.t loo ,p. I n e• ; • e nt t ha t ww u ms oo o te d. .Ldetea~lned rroA hIz.-oop. date. ~ ,-* Figure D14. The focal mechanism solutions for this Gold Mountain. Nevada (Ubebebe Crater :quadrangle), eazthquae all display-normal *slip. -Some solutionsi have a -shllow dipping nodal . ... ,-plane (possibly indicating a scismically active detachmient fault). - 87 I 2------I" - ' , -I -;I:.- , -,-- ',,A. - f., , -'- . z1 -E K.~ NpRRN, Ir Sazi plunge PJ aris 37.28 8.43 LOWER PAHRANAGAT LAKE SE T axis 301.99 39.29 DATE&TInE: 911107 2 47 13.21 B axis 134.99 49.98 LAT:., 37.091 LONG: 115.105 X airs 253.17 21.63 DMEPH. km. 7.39 +/- 1.1 ML 3.8 Ye axis 357.40 31.80 DIL]N (kin)-' 11.4 strike dip rake So]In 1 87.40 58.20 25.70 Vae 2 87.50 63.00 This event's agnltude In based on 30.70 LSN's SS-"pIltude on 1 (not be bi asd highh. OaIOONik or a oeMW%.1o0m-Tto I'oOeleteo Ii " o~our foe stotionis W# and E9. These statlons, ore, 3 I k e-romthe e oimeter. and their first notions We-euoA.OdLt Gb•UOU for- this ee-thquOka. Figure DIS., The focal mechanism solutions for this 7.4 km below sea level Pahranagat Shear Zone earthquake of November 7, 1991, display nodal planes with predominantly strike slip motion, although a substantial component of thrust is also present. 88 t,] .4 I r I P. •:~... DL "I-- -- P 4xs21 . plunge o PT axs 215.93 4.68 LOWER PAHRANACAT LAKE SE - '- " axis 124.78 64.75 DATE&TILE: 911107 2 47 13.25 X axis 241.41 24.78 LAT: 37.098 LONG: 115.108 -Y axjs 15.50 44.18 35.60 D=•IDEPTH. (kcm)-j-10.8"° k1m: 9.50 +/- 0.8 UL: 3 8 •-sreArie D 1Soln 1 105.50 dip rake 54.40 59.00 .... Var 2' 111.50 57.40 66.00 Thls fixed depth "= 8"teat 3.5 k, - Var 2" 103.40 52.20 50.80 beI~ow e. I ve wlJetrove residual I Is at a flt Atr. zof ro 7 to 9.5 k.)"' har r-* thrust ooppanet to the foool-. eeohonlas,~ than~ the troe-depth main. Figure D16. The alternate focal mechanism 3slutiuns for this Pahranagat Shear Zone, Nevada, earthquake of November 7, 1991, display greater amounts of thrust than the solutions shown in - figure D15. These soldtions correspond 'to a hypocenter fixed at 9.5 km below sea level. 89 I •===I 1' K .4 -E y azi plunge s202.13 45.08 SPEiTER RANCE NIW T axis 108.55 3.56 DATE&TIME: 911130 8 45 58.39 .X B axle811s 254.4815.01 27.1844.70 LAT: 38.739gLONG: 116.215 Y axis 145.00 33.00 -DEPTH. k= 5.58 +/- 0.8 DMIN,(Icm)- 5.1 ILL: 3.0' 1 strike4s 3 SI 5Soln dip rake 1 235.00 57.00 -33.00 I "Var 2 239.00 46.00 -26.70 : NIEIC aognitude 3.3. This eorthc•,•-e Var 2" 232.00 62.00 ollmed all SGSH mtation - -49.00 esoIK'PlOt *9treate~hd .PolitaPI asa r9.rtPOOl.;.o-ated PAYN.ot CIR and SOH an .pd wrlval. dlepl"oe polorlf9 or-c for.- l olutlons. Figure DI7. The focal mechanism solution, for this November 30, 1991. earthquake in the southern Nevada Test Site display 'oblique strike slip normal slip. The next figure also deals with this earthquake's focal mechanism data. 90 qy (U if"1 - if -.... , y.- ,'I I Nov 30,""1991 Focal Mech. "f i . * O0 w,0 t: if-if- -.20, S V V V V VVV V .40 *i I. (0) 7I100 _J if if if V ifif - .4 U) if if if if- - if if if. -if if .4ififififififif I r. I -120 000o 0 i0 0 0 -140 0 0 0 0 0 0 a 00 0 0 -160 I I II -180 I I I 30.0 40. 50.0 60.0 70.0 3 O.' 90.o DIP (degrees) range Figure D18. For the Specter Range NW earthquake of November 30, 1991,06:45:56 UTC, the are plotted, using of dip angles and corresponding slip angles consistent with SGBSN first motions trending a V symbol for the (dip, slip) pair corresponding to each plausible northeast-southwest The symbols nodal plane, and using a o symbol for each north-south nodal plane (see Figure D17). nodal planes are filled in for the "preferred rolutior' (dip, slip) pairs, which are shown as solid-line in nodal in Figure D17. This plot is provided as evidence that an approximate ±"10* uncertainty at least for the plane dip and slip angles, mentioned in Table 3 cf the text, can be demonstrated, better-constrained SGB earthquake focal mechanisms. 91 (1] S/:q __L r- . ,.'!. '3..'. I Appendix E Station codes, locations and site geology, and instrumentation Appendix E contains a list of SGBSN station names, mation. Instrument coordinates, and other descriptive infor codes-refer to the "seismome-tei,_"'amplifier/VCO), for each station. and discriminator packages For the current network, codes I through systems hiving 7 are valid. Any other codes are unknown frequency response and which for following are no longer operating in the SGBSN. iable shows the major components comprising The the seven current2 seismographic systems. Table El. Major components in seismographic systems comprising seismometers have the SGBSN in 1991. All natural frequency, J, 1.0 Hz. The digitized (analog) output of the discriminators on a PDP 11/34 computer, with sampling is rate = 104.167'spes/channel - i KIND SEISMOMETER Motion Aplifierv 1 Mark L4C vertical Tricon 649 D)iscriminator Tnicom 642 2 Teledyne S13 vertical 'ricom 649 3 Teledyne S13 vert., Tricom 642 horiz. Teledyne Geotech 42.50 4 Mark L4C Teledyne 4612 vertical Teledyne Geotech 5 Mark 42.50 Tricom 642 L4C horizontal Teledyne 6 Geotech 42.50 Teledyne 4612 Teledyne S13 vertical Teledyne 7 Ranger RR-o Geotech 42.50 Tricom 642 vertical Teledyne Geotech 42.50 Teledyne 4612 me F;,.#: a - . in Rogers'and..... others.u (1987b)for representatLive seismographic systems in the SGBSN may be found and in Harmsen and Bufe (1991). Ro'ck types and geologic ages each static.n are listed in table E2. at I SJ I 92 * *'w - '-'.it. "°" ' Table E2.SGBSN station sitegeolog (ýre min=). STA S-" - "RockType Geologic Age Tertiary AA4R Conglomerate APKW Limestone, dolomite Paleozoi BGB Bedded tuff Tertiary "-BLT Ash-flow tuff Tertiary BMTN "Trachytelava Teritazy CDHI Argillite Mississippian Cambrian - Limestone •CTSCPY Intrusive macc rocks Tetiary Paleozoic DLM Limestone, dolomite E,%QI Andesite and basalt flows Tertiary SEPMi'EIMN .. Ash flow'tuff Tertiary EPR Volcanicrock Tertiary FMT Metamorphic rock Precambrian GLR Limestone and dolomite Paleozoic GMN Granite Mesozoic GNMR Limestone and dolomite Paleosoic GVN Fanglomerate Tertiary GWY Volcanic rocks Iocene Tertiary HCR Ash.flow tuff JON Quartzite Precambrian KRNA Ash-flow tuff Tertiary "LCH Lim'Stone axid dolostone Cambrian Tertiary LOP * - Lava Tertiary LSM -. 'Basalt . MCA Limestone, dolostone Paleozoic MCY 2 --Dolomite, Irmestone - Dev6nlax MGM Quartzite Precambrian MTI Carbonates Devonian MZP, Volcanic tuff Tertiari Paleozoic : NOP •Limestone NPN Ash-flow tuff -- Tertiary, "PAN "Limestoni and dolostone Cambrian PPK' Granite Mesozoic PRN Ash-flow tuff Tertiary QCS Basalt Tertiary QSM -.- Tuft Tertiary - 7 -" Quartzite Precambrian 'SDH Miocene "SGV o •Rhyolite- SHRG Limestone,dolomaite "Cambrian Tertiary SPRG' TUJTffaceous sediments -4 1 'SRG -ý .rolcanicrocki Tertiary • -SSP "Ash-flow tuff 4 flows md breccias Tertiary 4 -4 -. * - rsVP "Andisite°- TCN Ash-flow tuff Tertiary TMBR Granitic ring-dike intrusion Tertiary TMO Limestone and dolomite Paleozoic TPU Shalis and sandstone Mississippiaa WCT Alluvium of Crater Flat Quaternary WRN Limestone aad dolomite *Ordovician YMT! Ash-flow tuff Tertiari' Welded :uff Tertiary tuff YNM C Welded Tertiary YMT4 Welded tuff Tertia~ry YMTS - Welded tuff Tertia~ry, e YMff6 Welded tuff Tertiary 93 99 STATION INFORMATION - SOUTHERN GREAT BASIN SEISMOrGRAPHIC NETO( PERIOD OF OPERATION LATITUDE LONGITUDE ELEVATION SEISMOUE-TER GAIN INST. CODE STATIcON (DEG MINUTES) (DEG MIUJTES) S (METERS) ,OOEL/CoLIP. (DO) CODE L '1 AMR Amargosa, Cal. 7 8/87/24-present 36 23.85 N 116 28.56 W 69e L-4C 84 1 APK Angels Peak. Neo. 75/06/15-81/83/21 36 19.17 N 115 34.46 W 2680 S-13 84 APK 81/03/21-838/84 2 -"C L-4C 84 APKW Neo. APtKI Angels Peak, 83/68/eae5-a/e/1 36 19.19 N 115 35.25 W L-4C 88/e8/Il-present 2600 84 L-4C 84 4 0 I BOB Big Butte. Nov. 7 9/O1/23-present C 37 02.24 N 116 13.75 W 1730 L-4C 84 BLT Belted Range. Neo. 79/65/36-present C 37 28.98 N 116 07.41 W 1854 L-4C 84 1 C I Black Mountain, Noe. 80/82/26-83/04/01 37 17.82 N 116 38.74 W EMTh 2191 L-4c 84 Black Mountain. Nev. 83/84/SI-present 1 37 17.50 N 116 38.41 W 2848 L-4C 84 BRO ,Bore Mountain. Ney. 78/11/28-81/4/88 36 45.76 N 116 37.52 W 926 L-4C 84 ,4 .4 CDHl Calico Hills. Now. 80/82/06-!1/i1/18 36 51.82 N 116 18.97 W 1353 Cc"' L-1-30S (vwrt.) 61/1i/-present L-4C 84 " Calico HIlls. Nev. 80/82/08-81/11/18 6 35 51.82 N 116 18.97 W 1055 L-1-30S horzntl 18 I CPx CP-I. Nev. 77/--8/63/6I. I 36 55.94 N 116 83.26 W 1258 NOC-21 ? -8/08/05-98/68/29 CPz L-4C 84 C cP-1. Nov. 98/e/2-h1/e1/15' 36 35.73 N 116 03.53 w I 0 1388 L-4C" 84 cPY "CP-I. Nov. 91/e1/15-prosent N 36 55.73 116 83.53 w 13"8 L-4C a84 1. 6 CTS C Cactus Peak,- Nov. 79/04/24-present 37 39.37 N 116 43.59 W: 1868 54 7 L-4C 84 0 DLy Delamar Mountains. Nov. 8/06/88-prosent 37-36.35 N 114 44.27.W 1730 8 OaN Eldorado Mtn.. Noey. 88/O8/11-92/05/14 35: 55.31 N C 114 45.33 W 846 Ranger SS-I 84 7, 92/05/14-present 35,55.31 N 114 45.33 W 846 L-4C0' 84 C *4 Echo Peak, Nov. 75/89/02-80/$4f25 C EP4 37 12.84 N 116 19.43 W 226" S-13 EPN 80/84/25-90/09/26 84 2 EPM 90 09 2 L-4C 84 4 C / / 6-present 37 13.57 N 116 20.01 W 2408 L-4C 84 4 C HEPN Echo Peak, Nov.' C 64/06/0"-86/01/28 37 12.84 N 116 19.43 W 2260 HEPW 88/61/2"9/0g/26 L-4C horizontal' 78 L-4C0horlzontal Go 5 C 96/09/26-present 37 13.57 N 116 20.88 W 2408 L-4C horizontal 60 C C EPR East Pahranagat Range. 7g/el/2,3-present 37 10.12 N 115 11.23 W Nov. 1305 L-4C 84 I S FlIT 7 Funeral Mountains, Cal. 8/11/28-prosent N 116 36 38.27 47.00 W 1625 L-4C 84 1 0 ...... ý.- ý11,;- 7-7(Th; WIPE r,, GLH Groom Loke Hood.,Nov. 75/11/20-preosent 37 11.94 N 116 e1.01 w 1432 L-4C 84 GUN Gold Uountaln. Nov. .. 79/07/13-present 37 18.04 N 117 15.44 W 2192 L-4C 84 4. CLNl# Gold Uountaln,. Nov. 84/87/30--prosent 37 18.04 N 11)7 15. 44W 2192 L-4C horizon tlot 78 5. Groom Range. Nov. 79/6I/23-present 37120.62 N 11' 46.36 W 1528 L-4C 84 4. Groom Range. Nev. 84/09/09-preosent ""'37 20.02 N 115 46.38 W 1528 L-4C horizon lal 78 5. Grapevine. GCVN Col. ,j78/1l/25-pree*nt 36 59.14 N 117 20.78 W 812 L-4C 8a4 Cre'enwater'Voalley. Cot. 78/07/24-88/62/16 36 11.11 N 116 40.22 W 1530 L-4C 84 Greenwater Valley. Col. 58/04/01-preosent 36 11.15 N 116 40.21 W 1540 L-4C 84 I ,,. fli' Creek Range. Nov. dl/b7/21-preuent 2048 38 14.01 H 116 26.28 w 84 Johnnle. Nev.. 78/07/24-prooent 36 26.39 N 116 06.28 W 916 L-4c 84 * Jc*1 4. ! Johrnlo.,Nov.. 84/86/22-prosent 36 26.39 N 118'0.28 W 916 L-4C horlzo ntal 78 5. ,Kowlch Range. Nov. 79/85/3"-86/64/22 37 42.37 r1 11a 2i.07 W 2576 L-4C 84 LJO - Kowlch Rango;eNov. 80/04/23-prosent "*37 44.53 N 116 2i.89 W 1963 L-4C 84 ISMLC" Last Change Range. Col: 79/87/13-present 37 13.95 N 117 38.78 W 1464 84 1.* I Lookout Peak. Nov. 79/61/23-preosent 116 1.1W 36 51.27 N 1648 L-4C 84 LittleSkull Ut., Nov. 79/12/13-84/87/23 36 44.55 N 116 16.33 W 4.• 4. 84/07/28-prement 84 LSCH ,-13 84 6 .e 1113 LSI 4 Little Skull Ut'.. Nov. 84/07/17-85/07/02 36 44.55 N 116 16.33 W LSLINLSS.4 85/67/02-86/01-28 L-4C horlzoni at 78 L-IC horlzoni at 72 5. 'LSMJ 88/6 /2o-86/06/24 5. .. 86/06/24-preoent L-4C horizonl at 60 S-13 horlzont at 38 4 Little Skull Ut.. Nev.1 84/37/17-85/67/02 36 44.55 N 116,16.33 W 1113 L-4C horlzont al 78 LSUE S. . 85/67/02-86/01-28 3.5.* LSUE 1-4C horlzont atl 72 5.• ,LSUE 88/61/28-856/6/24 L-4C horlzont al 60 ' J86/e6/24-Lprossnt S-13 horliont al 38 3.* MCA Uarble Canyon. Col. -79/81/23-prosent 36 38.77 N 117 16.69 w 270 L-4c 84 1. LUCY #.Uercury. Nev., 80/03/07-present 35 39:64 N 115 57.67 W 1303 S-I 3 84 2. Uogruder Uountaon,,Nov. 79/07/13-prosent 37 26.44 N 117 29.93 V 2075 L-4C 84 1.* UTI Mount Irloshj,1v.• 79/06/085-present 37 40.68 N 115 16.i2W 1540 84 u~p Uontezuma Peak. Nov. 79/07/13-present 37 42.03 N 117 23.10 i NUN 2353 L-4C 84 Nasa Mountain, Nev. 75/11/2 1. 83/11/01 37 64.85 N 116 49.69 W 1506 ft.4' - L-IC 84 ý 1, f. NOP Nopah Range. Cal. 78/C7/24-80/84/25 36 87.63 N 116 09.26 W oil L-4C 86/84/25-preosent S-13 84 84 2 1NPH North Pahro4 Rg. Nov. 79/8d/08-present 37 39.12 H 114 ?6.21 W 1668 L-4C 64 I PAN Panoaint Rang*, Cal. 8/64/01-provent 36 23.59 N 117 16.05 W 1690 L-4C 84 4 PAJil Panoaint Rang*, Cal. 88/84/0i-present 36 23.59 H 117 08.05 W 1698 L-4C horizontal 78 5 1 PGE Panamint Range. Cal. 78/11/28-88/02/13 36 20.93 N 117 83.95 W 1850 L-4C 84 4 PGEH Panadint Range. Cal. 84/18/1i1-88/2/13 36 20.93 N 117 83.95 W 1850 L-4C horizontal 78 PPK Piper Mountain. Cal. 79/07/13-present' 37 25.51 N 117 54.42 W 1851 L-4C 84 P1*4 Pahroo Rang., Nov. 72/01/21-88/06/19 S 8 37 24.48 N 113 01.05 W 1402 8/06.ý19-prsent, NCC-21 7 PR1* S-13 84 PRNIi Pahroc Hang#. Nov. 4 Vt 8 /08/28-present, 37 24.40 N 115 03.05 W 1482 L-4C horizontal 78 5.,6 OCS Summit. Noy. 79/66/08-pres ent 2 Queen City 37 45.39 N 115 56.58 W 1914 - L-4C 84 14• QO1 7 1 Queen of Sheba Mine. C,a 8/l1/28-proeent 35 N p. 57.85 116 52.05 W 456 L-4C 84 SDIf Striped.IIII1. Nov. 7 14• a/07/24-presant 36 30.72 P N 116 28.38 W 1050 L-4C 84 SGV South Grapevine UtI. Cc o 78/11/28-81/06/15 36 58.92 N 117 82.11 W 1550 D SGV 81/86/13-82/86/16 L-4C 84 S-13 SCG; 82/86/l5-presenLt 84 2.• '0 L-4C 84 rSIIRG 7 / Sheep Range. Nov. 9/85/22-present 34 38.33 N 115 09.61 W 0 1596 L-4C 84 I . SPRG Spotted Rang@. Nov. 79/05/28-preeent 36 41.64 N 115 48.63 W 1191 L-4C 64 SRG Seaman Range. 7 Nov. 9/06/08-preuont 37 52.93 N 115 04.15 W 1640 L-4C 84 1.• SSP ShoehonPeak, yNov. 73/10/10-80/05/25 36 •5.53 N 116 13.26 W 2821 SsP 8 0/85/27-prosent NCC-21 7 8 L-4C 84 7 1.• SVP Silver Peak Range. Nov. 9/07/1i-prA36.,4 37 42.89 11 117 48.28 W 2595 L-4C 84 TCH 1 * Thirsty Canyon, Nov. 84/1l/02-preosent 37 N 8.80 116 43.52 W 1.469 L-4C 84 Timber Ut., Nov. 82/02/19-87/85/85 37 02.11 N 116 23.21 W 1754 I a7/e5/85-present L-4C 84 S-13 84 6.* Tin Mountain. Cal. 7 8/11/28-present 36 48.29 N 117 24.30 W 7PU 2113 L-4C 84 I • 9 Te6plute Mountain, Nov. 7 /086/08-present 37 36.27 N 115 39.06 W 1910 L-4C 54 WCT Wildcat Mountain. Nov. 811/84/ea-88/oI/e5 36 47.79 N I • WC1 116 37.62 W 930 L-4C 84 88/B1/05-88/03/11 I.• 88/03/ll-prosent L-4C 66 L-4C 84 I • Worthington ti.., 7 Hey. 9/06/08-plresent 37 38.89 N 115 I • I 35.58 W 1725 L-4C 84 ) - 1 "Y4TI Yucca Mountain, Itav. 0t/a3/s5-present 36 SI.22 N Hey. 116 31.86 W 1006 5-13 . 84 YUT2 Yucca Mountain. 8t/03/e5-present 3 S 38 47.14 H 116 29.22 W 1006 5S-13 * 84 Hey. 8 YUT3 Yucca Mountain, 5 1/03/05--prssent 36 47.21 H 116 24.75 W 'S-13 Nov. "1060 84 YUT4 .4' Yucca Mountain. 36 56.99 N 116 27.18 W 3 S Ol/84/oi-oi/t/I13 1248 S-13 84 3 81/I1/13-83/07/81 S-13 72 3 5 03/87/02-present S-13 , 84 0 I YUJ4H Yucca Mountain. Hey. 84/86/29-85/85/23 36 50.99 Nl 116 27.18 W L-4C horlzontal 5 YU4S 85/05/24-88/81/28 1248 L-4C horizontal) 78 5 S a6/01/28-pr. int 72 5 5 L-4C horizontal* 60 '11J4 C C 'ruiw Yucca Uountaln. tNov. a4/06/29-85/05/23 36 50.99 H 116 27.18 W 5 S [Yu4 1248 L-4C horizontal 78 5 :5/85/24-86/01/28 L-4C horizontal 72 5 C 86/01/23-present L-4C horizontal 60 C Yucca Mountain. eyv. 5 81/:4/01-81/10/13 38 53.91 I1 116 27:25 W 1355 S-13 C yUt5 /87/13-83/87//2(?) 84 3 07 S-13 72 3 a / /02-prosent C S-13 84 3 YU'sYUTS Yucca Mountain. Hey. al/e4/81-81/te/13 3, "yula 38 51.38 H 11t 24.82 W 1to8 S-13ý 78 S 9al/10/13-83/87/e2(7)3 S-13 Z' 66 3 a /87/02-pressnt C I ýS-13 84 3 Cx C NOTES: All Instruments are vertlical-coaponent unless otherwise noted. If one •0 horizontal-coponent Instrument exists at a sit., It hoe north-soulh -,J polarity; If two horizontals exist at a sile, they hove north-south and east-woet polarities, reap. The polarity is suggested by the station name: A * In the final column Indicates satellite-deteroined station coordinates. Elevations of stations with se In the finai colm.n were obtained using altimeters calibrated against nearest USGS ben€chmark. Locations are preliminary. • t I :ý. Al I ! ! Appendix F Input parameters to HYPOTI Project, with CID HYPO71.FOR, version 1.001, was baselined for use by the Yucca Mountain a minimum YMP-USGS/GDD0001.02, on October 22, 1990. This version of HYPO71 requires weighting scheme of three input files: (1) a header file containing crustal velocity information, (2) a station file information, iteration-controlling parameters, and I/O-controlling, parameters; (3) a phase file, containing containing most of the information shown in Appendix E, above; and The data of P and S phase arrival times and information for determining earthquake magnitude. The data of item (3) are too item (1) are presented in Appendix E, and will not be repeated here. when approved by USGS-YMP extensive for inclusion in this report , but are available on request, management. occurring One of two header files is used, depending on the source'zone. For most earthquakes Fl (a) is input., For in the SGB, the file nvhead.dat, having the velocity model shown in figure nvhead.ymt, having earthquakes occurring in the immediate vicinity of Yucca Mountain, the file shown on the next the velocity model qhown in figure Fl (b), is input. Copies of these two fi'-s are Lee and Lahr page. For meanings of the "Control Card' parameters, the reader should consult (1975). 98 ,K * .Af ' used as an Input file to HYP071. (A) The below lines are a listing of nvhoed.dat. HEAD RESET TEST )-. 0.5500 RESET TEST 2) 2e.0eee RESET TEST 3)- 8.5004 RESET TEST 4)- e.0500 RESET TEST S - 5.0000 RESET TEST 6)- 1.0eet RESET TEST 7]- -1.2760. RESET TEST 86- 1.6660. TEST I9- e.Ge227 RESET lon /solut ion RESET TEST 1- 108.0o00 Imax f of i erot RESET TEST 11 - 12.0MOM RESET TEST 12 - -. 5M RESET TESTI 13 - 1.000 RESET TEST 14 - -2.050. RESET TEST 15."- 0.000 RESET TEST 16 - 0.852 RESET .TEST 17 - -1.766 S .38eeeeeE1 *.000SOME+0 .59eeewEe+0E1 .10000.E0 el .615"0I0E+01 .300eeeebE+ei .650000e441 - 15800000E+02 .69000000E+81 .24eeeeeE+02 .7880~00E+01 .32e000eeE+e2 .eeeoe"OeE+0e .0000e0eeE+0. a 0 0 81- 7 0 1 1111 - 6.0. e 0.0 : - 7. 10. 220. 1.71 3 ueod as an Input file to mYPO71. (B) The below lines are a listing of nvhead.ymt.Q HEAD RESET TEST( 1)-1: .100 RESET TEST 2)- 3e.000. RESET TEST( Z.- .5000 j RESET TEST 4- '.e0500 RESET TEST 51- 5.:000 RESET TEST 6- '1.0OW RESET TEST 7- -1.27"0 RESET TEST I-1. 0 0.. RESET TEST 9a- e.00227 RESET TEST 10 .- ee.0e0. I RESET TEST 11 -,, 8.000. RESET TEST 12 e.-•,6 e. RESET TEST 13 - 1.-.LO RESET TEST 14 - -1.2*00 RESET TEST 15C- 0.0000 RESET TEST 16 - a.652 RESET TEST 171- -I.766 - -• -. -. 32000000E+81 .eON3WE+00-. Z - .46ee80Ee0 +e1 .e540E1r1 .57000e E+01 .25•0eee+el . 1 .62000000E+01 - .4.000~0OE+401 .6500s0 rE+01 .150e000 tE+02 .7800000eE+e1 .3200000eE+02 . ee oeeOE+00 . 000e0000 0.+0 0.00 0 0.00 0 7 8 1 1111 0 7. 5. 90. 1.71 3 a e scheme with respect to In file (B), o slightly different weighting file, weights in nvhead.dat. file (A) above. In the former distance is Invoked than distances between 1. to 0. In a linear manner for Iplcentral taper from toper from 1. to 0. for distances le and 220 lim. In the latter file. weights between 5 and 90 km. 99 ! ! lOE .,,-. it (a) 0 i 2 3 4 5 6 7 8 (b) 0 I 2 ý3 456 7 a A! , . I I I I ; I I I VELOCITY (Ki1/SE-C) "VELOCITY (KtA/SEC) Figure F1. (a) Primary (P) and secondary (S) wave velocities as a function of depth (0.0 = sea level) for the standard model used to locate southern Great Basin earthquakes. The interface km is optional. at 15 (b) P and S wave velocities as a function 'of depth for the Yutcia Mountain being region, an idealization of the model proposed by Hoffman and Mooney (1984). *U.$. GOVERNMENT PRINTING OFFICE: 1993-774-207/60030 100 )(D1o; IL :1'".. 7-, ;. i<. I SoqL• The following number Is for U.S. Department of Energy Office of Civilian Radioactive Waste Management purposes only and should not be used when ordering this publication: Accession Number NNA.920629.0129 10-7