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Northern California Weekly Seismicity Reports

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Northern California Seismicity Report for the week ending Dec 20, 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

  • 16 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 light earthquake of magnitude 4.0, 9 miles SSE of Ukiah, CA at 09:41 AM UTC Friday, 12 14, 2001 (01:41 AM PST Friday, Dec 14, 2001).
Additional information about this quake can be found at the UC Berkeley Seismological Laboratory.
  • 11 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 2.3, 5 miles ENE of Gilroy, CA at 01:28 PM UTC Tuesday, 12 18, 2001 (05:28 AM PST Tuesday, Dec 18, 2001).
  • 16 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 2.7, 12 miles SW of Toms Place, CA at 03:02 PM UTC Saturday, 12 15, 2001 (07:02 AM PST Saturday, Dec 15, 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 13 0603  7.80 36 31.12 121  6.07 10.60 54 .07  .1  .3 PIN    2.1D  47  2 NN
2001 DEC 14 0002 59.27 36 33.36 121  3.36  7.85 26 .09  .2 1.3 BVL    2.0D  70 24 NN
2001 DEC 14 0941  5.84 39  2.73 123  7.24  6.94 36 .07  .2  .5 MAA    4.0L  32  9 NN
2001 DEC 14 1927 56.00 38 49.44 122 45.85  2.43 33 .06  .1  .3 GEY    2.5D  49  3 NN
2001 DEC 15 0034 46.25 39  2.86 123  7.54  6.54 29 .07  .2  .6 MAA    2.2D  36  9 NN
 
2001 DEC 15 1502 42.87 37 27.06 118 51.19  6.58 37 .07  .3 1.3 MOR    2.7D  90 12 NN
2001 DEC 15 1536 46.22 37 26.98 118 51.21  7.31 38 .07  .3 1.4 MOR    2.5D  90 12 NN
2001 DEC 15 2251 28.89 37 55.18 122  3.19 10.35 54 .18  .2  .3 CON    2.1D  54  5 NN
2001 DEC 16 1216 17.03 37 28.69 121 42.93  9.53 75 .07  .1  .3 HAM    2.2D  37  6 NN
2001 DEC 16 1722 22.02 37 19.74 120  1.09 15.75  8 .01  .5  .9 KAI    2.1D 168 26 NN
 
2001 DEC 18 0754 58.91 35 59.31 120 32.12 10.94 42 .04  .2  .2 MID    2.1D  88  5 NN
2001 DEC 18 1328 19.67 37  2.67 121 29.18  7.00 60 .09  .2  .3 CYS    2.3D  54  2 NN
2001 DEC 18 1746 37.31 36 23.00 120 57.61  7.58 42 .07  .2  .4 BIT    2.5D  70  7 NN
2001 DEC 19 0050  0.41 36 40.96 121 18.41  4.07 37 .06  .2  .4 STN    2.1D  33  3 WW
2001 DEC 19 0832 38.42 38 46.17 122 44.47  2.75 31 .06  .1  .4 GEY    2.3D  52  2 WW
 
2001 DEC 19 1126 17.40 36 40.99 121 18.59  4.65 49 .05  .1  .3 STN    2.3D  59  4 WW