Northern California Seismicity Report for the week ending Apr 26, 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

• 27 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 4.2, 56 miles W of Ferndale, CA at 05:19 AM UTC Friday, 04 20, 2001 (10:19 PM PDT Thursday, Apr 19, 2001).

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

The largest event to occur this week in this region was an earthquake of magnitude 2.5, 4 miles WNW of San Juan Bautista, CA at 07:30 AM UTC Friday, 04 20, 2001 (12:30 AM PDT Friday, Apr 20, 2001).

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

The largest event to occur this week in this region was a minor earthquake of magnitude 3.1, 5 miles SW of Toms Place, CA at 01:52 PM UTC Friday, 04 20, 2001 (06:52 AM PDT Friday, Apr 20, 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 19 1846  9.75 38 49.45 122 48.30  1.97 31 .03  .1  .2 GEY    2.1D  34  2 NN
2001 APR 20 0519 51.41 40 41.12 125 19.04  2.94130 .21  .918.8 DEL  - 4.2L 233 86 NN
2001 APR 20 0730 44.66 36 51.72 121 35.94  7.66 65 .09  .1  .2 SJB    2.5D  51  3 NN
2001 APR 20 0848 51.04 38 49.44 122 48.19  4.68 41 .04  .1  .3 GEY    2.3D  33  2 NN
2001 APR 20 1352 55.03 37 29.98 118 44.08  8.48 34 .06  .2  .6 WCN    3.1D 112  2 NN
 
2001 APR 21 0000 33.32 40 56.95 123 48.70 30.01 14 .07  .4  .6 EUR    2.4D 114 11 NN
2001 APR 21 0231 37.05 38 49.77 122 46.90  1.68 19 .05  .2  .4 GEY    2.1D  40  3 WW
2001 APR 21 0542 11.78 38 46.28 122 43.33  2.25 13 .05  .3  .4 GEY    2.0D  60  0 WW
2001 APR 21 1106 47.35 40 43.14 123 29.48 37.90 11 .50 2.3 4.8 EUR    2.6D  78 20 WW
2001 APR 22 0004 14.12 37 38.69 118 21.14  4.79 31 .06  .5  .7 WHI    2.6D 179  6 NN
 
2001 APR 22 0308 41.60 39 18.27 122 47.35  9.94 20 .05  .2  .9 BAR    2.1D  78 16 WW
2001 APR 22 0356 33.27 37 29.18 118 50.46  3.79 36 .07  .3 1.1 MOR    2.9D  83 11 NN
2001 APR 22 0414  1.48 37 29.19 118 50.40  3.19 29 .04  .3 1.1 MOR    2.1D 180 10 WW
2001 APR 22 0414  1.48 37 29.19 118 50.40  3.19 29 .04  .3 1.1 MOR    2.1D 180 10 WW
2001 APR 22 0616  6.98 36 36.31 121 10.49  6.23 22 .07  .2  .7 PIN    2.5D  49  7 WW
 
2001 APR 22 0749 12.23 37 38.76 118 20.67  5.70 10 .04 1.0 1.1 WHI    2.2D 200  6 WW
2001 APR 22 0924 27.77 37 38.85 118 21.13  5.56 21 .07  .6  .8 WHI    2.2D 226  6 WW
2001 APR 22 2210 55.72 37 28.83 118 50.42  4.22 33 .06  .3 1.2 MOR    2.4D 127 11 NN
2001 APR 23 0348 53.15 36 34.58 118 17.91  0.57 21 .05  .9 5.2 BAK  # 2.8D 164 80 NN
2001 APR 23 1038 57.41 38 49.78 122 48.33  2.68 18 .03  .2  .4 GEY    2.1D  43  3 WW
 
2001 APR 23 1049 56.86 38 48.45 122 49.01  4.13 37 .03  .1  .2 GEY    2.0D  31  2 NN
2001 APR 23 1507 28.36 37 13.61 118 35.35 13.47 23 .04  .5  .7 KAI    2.3D 227 12 WW
2001 APR 23 2008 54.83 36 34.06 121  5.55 22.72  8 .42 5.914.8 BVL    2.0D 169  7 WW
2001 APR 24 1157  0.48 36  0.73 119 56.05  9.41 38 .15  .5  .7 COA    3.3L 194 17 WW
2001 APR 24 1207 31.98 36  0.44 119 57.80  5.98 23 .14  .5  .9 COA    2.3D 199 16 WW
 
2001 APR 24 1732 18.73 38 48.23 122 44.30  2.28 17 .05  .2  .5 GEY    2.2D  62  4 WW
2001 APR 25 0227 52.44 39 57.25 123 34.37  3.22  8 .06  .6  .6 MAA    2.2D 142  5 WW