Northern California Seismicity Report for the week ending Apr 12, 2001

This report provides a brief summary of earthquake activity recorded by the U.S. Geological Survey Northern California Seismic Network in Menlo Park and the University of California Berkeley Seismological Laboratory. It is automatically generated each Wednesday shortly after midnight, Universal time (UT). UT (ie., Greenwich Mean Time) is 8 hours ahead of PST or 7 hours ahead of PDT.

Because it is not possible to review all of the earthquakes before this report is generated, it may contain errors. Please report errors or provide suggestions and comments to ncsn@andreas.wr.usgs.gov

The report no longer includes maps showing earthquakes for the entire US or world. Those maps are now available from the U.S.G.S. National Earthquake Information Center. In addition, all earthquake data can be retrieved from the Northern California Earthquake Data Center.

Please note that some of the earthquake data in this report have been reviewed by seismic analysts. Consequently, the parameters that describe the hypocenter, magnitude, origin time, and solution statistics may differ slightly from the information contained on the real-time earthquake web page. The differences reflect revised arrival times at seismic stations and the analysts' decisions to include or exclude information from seismic stations.

The minimum magnitude ( M) values in the following bullets reflect the smallest earthquake which the network can routinely record within the region. During the previous seven-day period ending at midnight (UT) Wednesday, our seismic networks recorded

• 19 M >2.0 earthquakes in Northern and Central California (map) (within dashed polygon of figure).

The largest event to occur this week in this region was a minor earthquake of magnitude 3.2, 2 miles S of San Juan Bautista, CA at 04:13 AM UTC Sunday, 04 08, 2001 (09:13 PM PDT Saturday, Apr 07, 2001).

A M2.7 event occurred Sunday afternoon about 2 miles N of San Leandro (02:20 PM PDT; 21:20 UTC; 04 08 2001). It was lighltly felt in the immediate area and weakly felt as far away as the Napa Valley. A M2.8 earthquake occurred Monday morning at 09:49 AM PDT (16:49 UTC, 04 09 2001) in northern California about 43 miles northeast of Eureka. With a focal depth of about 35 km, this event was located within the subducted part of the Gorda Plate, the ocean plate that underthrusts the Klamath Mountains.

• 17 M >1.2 earthquakes in the San Francisco Bay area (map).

The largest event to occur this week in this region was a minor earthquake of magnitude 3.2, 2 miles S of San Juan Bautista, CA at 04:13 AM UTC Sunday, 04 08, 2001 (09:13 PM PDT Saturday, Apr 07, 2001).

• 16 M >1.2 earthquakes in the Long Valley region (map).

The largest event to occur this week in this region was an earthquake of magnitude 2.9, 8 miles WSW of Toms Place, CA at 07:02 AM UTC Friday, 04 06, 2001 (12:02 AM PDT Friday, Apr 06, 2001).

The following table provides a listing of all M >2 earthquakes that occurred this week. An explanation of the entries in the table is available.

---ORIGIN TIME (UT)--- -LAT N-- --LON W-- DEPTH  N RMS ERH ERZ LOC    PREF AZ MIN S. PAGE   1
YEAR MON DA HRMN  SEC  DEG MIN  DEG  MIN    KM  RD SEC  KM  KM REMKS  MAG  GAP DS PF

2001 APR  5 0708  7.29 39 41.96 121  6.18  1.44 22 .07  .6 7.7 WAK  - 2.3D 178 22 NN
2001 APR  5 1449 51.76 35 36.54 119 54.66  6.31 31 .11  .4  .5 BAK    2.3D 169 15 NN
2001 APR  6 0423 49.75 35 51.08 120 23.71  5.48 45 .05  .1  .2 GOL    2.4D  70  2 NN
2001 APR  6 0657 38.94 37 32.29 118 48.86  6.72 33 .06  .3  .6 MOR    2.5D 110  6 NN
2001 APR  6 0702 24.12 37 32.32 118 48.83  6.77 33 .05  .3  .6 MOR    2.9D 109  6 NN
 
2001 APR  6 1136 46.84 37 32.30 118 48.86  6.86 33 .06  .3  .6 MOR    2.8D 109  6 NN
2001 APR  6 1205 49.01 37 32.22 118 48.77  6.65 31 .05  .3  .6 MOR    2.3D 110  6 NN
2001 APR  6 1942 37.51 36 41.94 121 50.73  6.95 61 .06  .2  .7 SAL    2.3D 111 13 NN
2001 APR  7 0637 14.47 37  7.95 121 59.03 13.81 66 .08  .2  .3 LOM    2.3D  65  6 NN
2001 APR  8 0250 13.54 37 32.02 118 25.91  5.16 29 .05  .3  .4 CHV    2.2D  95  2 NN
 
2001 APR  8 0413 42.07 36 49.04 121 32.03  5.03 63 .13  .1  .3 SJB    3.2L  33  3 NN
2001 APR  8 0428 24.18 36 48.77 121 31.59  4.07 48 .16  .2  .4 SJB    2.3D  35  3 NN
2001 APR  8 2120  0.38 37 44.89 122  9.02  5.53 74 .09  .1  .3 HAY    2.7D  28  4 NN
2001 APR  9 0151 36.34 37 39.01 118 20.53  5.95 28 .07 1.0 1.0 WHI    2.5D 196  6 NN
2001 APR  9 1649  8.41 41  5.06 123 25.06 39.68 20 .08  .3  .4 KLA    3.1D  55 22 NN
 
2001 APR  9 2225 47.11 36 41.34 121 19.13  5.94 56 .07  .1  .3 STN    2.9D  64  3 NN
2001 APR  9 2308 17.70 36 41.42 121 19.23  5.77 56 .05  .1  .3 STN    2.6D  64  3 NN
2001 APR 10 0034 43.05 37 28.35 118 50.21  5.55 27 .06  .4 1.0 MOR    2.2D 130 10 WW
2001 APR 10 0254  8.19 36  3.57 120  4.95 10.59 51 .18  .3  .2 COA    2.3D 144  2 NN