Northern California Seismicity Report for the week ending Dec 27, 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

• 20 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 an earthquake of magnitude 3.4, 7 miles NNW of Avenal, CA at 08:25 AM UTC Thursday, 12 20, 2001 (12:25 AM PST Thursday, Dec 20, 2001).

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

The largest event to occur this week in this region was a microearthquake of magnitude 2.6, 1 miles ENE of San Ramon, CA at 03:19 PM UTC Monday, 12 24, 2001 (07:19 AM PST Monday, Dec 24, 2001).

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

The largest event to occur this week in this region was a microearthquake of magnitude 2.5, 11 miles WSW of Toms Place, CA at 08:58 AM UTC Tuesday, 12 25, 2001 (12:58 AM PST Tuesday, Dec 25, 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 DEC 20 0825 16.55 36  5.41 120 11.71  8.32 35 .10  .2  .3 COA    3.4L  83  8 WW
2001 DEC 20 0847 42.42 36  5.56 120 11.38  8.55 21 .04  .2  .3 COA    2.4D  87  8 WW
2001 DEC 20 1438  1.24 38 12.99 122 11.73  9.26 15 .22  .7 1.4 NAP    2.1D 133  7 WW
2001 DEC 20 1741 46.11 37 26.32 118 51.09  7.42 30 .07  .4 1.5 MOR    2.3D 142 13 WW
2001 DEC 20 1919 41.88 38 50.23 122 52.81  1.55 26 .10  .2  .7 GEY    2.8D  38  4 WW
 
2001 DEC 20 1920 38.39 36  5.59 120 11.86  8.01 14 .03  .2  .4 COA    2.3D 118  9 WW
2001 DEC 20 2300 37.80 37 18.69 122  6.34  0.04  9 .08  .4 1.4 BLM  # 2.2D 101  3 WW
2001 DEC 21 0137 22.13 38 49.13 122 48.80  2.22 16 .07  .2  .5 GEY    2.1D  77  2 WW
2001 DEC 22 0311 36.64 40 23.83 124  5.37 21.77  9 .02  .4  .4 MEN    2.6D  95 23 WW
2001 DEC 22 0941  4.52 36  5.55 120 11.88  5.73 28 .28  .6 1.0 COA    2.3D 100  9 WW
 
2001 DEC 22 1039  5.30 36  6.41 120 12.52  5.33  8 .04  .7 1.2 COA    2.1D 119 10 WW
2001 DEC 23 0711 26.45 37 26.22 118 51.08  7.01 28 .06  .4 1.5 MOR    2.1D 142 13 WW
2001 DEC 24 0210 18.15 36 49.14 121 32.61  5.65 39 .09  .2  .4 SJB    2.1D  36  4 WW
2001 DEC 24 1519 20.68 37 47.03 121 57.29  9.66 59 .13  .2  .3 DAN    2.6D  94  9 WW
2001 DEC 24 2354 50.86 36 47.78 121 22.62  3.92 44 .08  .2  .3 HOL    2.2D  48  3 WW
 
2001 DEC 25 0254 27.22 38 48.75 122 48.86  4.14 21 .06  .2  .5 GEY    2.0D  51  2 WW
2001 DEC 25 0857  3.97 37 28.67 118 50.68  5.82 30 .07  .3  .9 MOR    2.3D 129 11 WW
2001 DEC 25 0858 48.75 37 28.64 118 50.69  5.64 34 .08  .3 1.0 MOR    2.5D 129 11 WW
2001 DEC 25 1901 15.32 36 19.37 120 42.17 10.95 34 .14  .3  .4 CRV    2.4D  84 12 WW
2001 DEC 26 1752  6.50 36 42.57 121 20.39  2.82 49 .08  .2  .3 STN    2.7D  54  0 WW