Northern California Seismicity Report for the week ending Mar 01, 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

• 23 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 4.4, 11 miles E of San Jose City Hall, CA at 11:18 PM UTC Sunday, 02 25, 2001 (03:18 PM PST Sunday, Feb 25, 2001).

This magnitude 4.4 earthquake was on the Calaveras Fault immediately north of the epicenter of the magnitude 6.2 Morgan Hill earthquake in 1984. It had a typical right-lateral strike-slip focal mechanism. Magnitude 4 earthquakes are frequent in this area. It was widely but lightly felt throughout the bay area. For additional information see http://quake.usgs.gov/recenteqs/quakes/nc51105698.htm.

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

The largest event to occur this week in this region was a light earthquake of magnitude 4.4, 11 miles E of San Jose City Hall, CA at 11:18 PM UTC Sunday, 02 25, 2001 (03:18 PM PST Sunday, Feb 25, 2001).

• 11 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, 13 miles SW of Toms Place, CA at 12:08 AM UTC Saturday, 02 24, 2001 (04:08 PM PST Friday, Feb 23, 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 FEB 22 1220  8.18 36 53.96 121 37.61  5.30 57 .10  .1  .2 SJB    2.3D  41  4 NN
2001 FEB 22 1936 26.19 38 48.32 122 49.12  1.76 23 .04  .2  .3 GEY    2.1D  37  2 NN
2001 FEB 22 2256  3.06 37 15.74 119 57.13 18.10 11 .02  .4  .5 KAI    2.5D 161 17 NN
2001 FEB 22 2301 52.92 37 17.23 119 53.00 12.18 11 .03  .4  .6 KAI    2.4D 104 19 NN
2001 FEB 22 2316 13.12 37 16.68 119 58.89 10.98 10 .32 1.3 2.5 KAI  # 2.1D 131 19 NN
 
2001 FEB 23 0432 18.00 36 10.60 121 35.52 12.03 31 .05  .2  .3 SUR    2.1D 130  5 NN
2001 FEB 23 2058 46.56 37  4.66 121  2.54  7.09 56 .17  .4  .8 ORT    3.1l 153  8 WW
2001 FEB 23 2103  7.52 37  4.67 121  2.63  2.69 37 .14  .3 5.6 ORT  # 2.5D 123  8 WW
2001 FEB 24 0001 32.83 38 48.00 122 48.82  3.90 15 .03  .2  .4 GEY    2.1D  62  2 WW
2001 FEB 24 0008  0.16 37 26.97 118 52.36  7.35 31 .06  .3 1.4 MOR    2.7D 139 14 WW
 
2001 FEB 24 0733 50.86 38 49.51 122 50.07  1.34 19 .04  .2  .5 GEY    2.4D  45  4 WW
2001 FEB 25 0136 59.86 35 27.72 120 46.39  0.02 28 .11  .2 3.7 SSM  # 2.6D  79 10 WW
2001 FEB 25 0143 21.14 36 48.09 121 30.87  6.03 44 .10  .2  .4 SJB    2.4D  35  2 WW
2001 FEB 25 0237 55.37 40 44.52 124  6.64 20.95 13 .08  .5  .7 EUR    2.9D 156 35 WW
2001 FEB 25 0913 48.66 35 27.43 120 46.64  2.73 14 .05  .3 1.2 SSM    2.1D 131 10 WW
 
2001 FEB 25 1156 51.41 38 47.78 122 46.49  1.36 16 .17  .5 1.4 GEY    2.3D  90  6 WW
2001 FEB 25 1158 40.18 36 27.55 120 18.26  3.89 18 .11  .3  .4 COA    2.4D 182  9 WW
2001 FEB 25 2318 22.50 37 19.98 121 41.92  7.76 78 .06  .1  .3 SFL    4.4l  41  6 WW
2001 FEB 25 2327 56.56 37 19.94 121 41.95  7.16 57 .06  .1  .5 SFL    2.1D  54  6 WW
2001 FEB 27 1325  6.42 37 34.35 118 50.60  6.78 32 .06  .2  .4 MOR    2.3D 100  2 WW
 
2001 FEB 28 0225 16.16 38 47.28 122 46.43  1.00 17 .04  .2  .4 GEY    2.1D  88  3 WW
2001 FEB 28 0227  2.22 38 47.75 122 47.08  0.39 15 .05  .2  .4 GEY    2.0D  87  2 WW
2001 FEB 28 1856 46.32 37 38.82 121 57.71 30.00 15 .30 7.7 5.8 DAN  # 3.7l 235 11 WW