Northern California Seismicity Report for the week ending Jul 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

• 17 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 3.7, 4 miles E of Rohnert Park, CA at 03:07 PM UTC Friday, 07 06, 2001 (08:07 AM PDT Friday, Jul 06, 2001).

See San Francisco Bay write-up below.

• 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 3.7, 4 miles E of Rohnert Park, CA at 03:07 PM UTC Friday, 07 06, 2001 (08:07 AM PDT Friday, Jul 06, 2001).

Based on the location and right-lateral strike-slip focal mechanism, this quake likely occurred on the Rodgers Creek fault. Since 1971 there have been 12 quakes above M3 within 8 km (5 miles) of this quake. The largest quake to precede this quake was the 9/22/1999 M4.2 event about 5.5 km to the north. User responses indicate that this quake was widely felt in the North Bay as well as instrumental recordings depicted on ShakeMaps.

• 8 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 2.6, 10 miles WSW of Toms Place, CA at 02:08 PM UTC Monday, 07 09, 2001 (07:08 AM PDT Monday, Jul 09, 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 JUL  5 0116 41.84 39 14.32 123  7.33  7.03 19 .04  .2 1.0 MAA    2.2D  79 13 WW
2001 JUL  5 0310  3.05 36 41.56 121 19.41  4.85 40 .05  .2  .4 STN    2.2D  43  3 WW
2001 JUL  6 0527  4.62 36 41.04 121 18.64  4.36 51 .05  .1  .2 STN    2.0D  35  4 NN
2001 JUL  6 1331 45.14 36 58.38 121 27.60  4.62 71 .12  .1  .3 CYS    2.8D  39  5 NN
2001 JUL  6 1337 32.80 36 58.41 121 27.73  4.94 71 .12  .2  .4 CYS    3.0D  43  5 NN
 
2001 JUL  6 1507 31.95 38 20.69 122 38.07  7.22 60 .13  .2  .3 ROG    3.7L  45  5 NN
2001 JUL  6 1759  2.62 38 55.49 122 31.95  5.86 28 .10  .2  .8 BAR    2.3D  95 12 NN
2001 JUL  6 2114  5.76 36 24.93 120 59.67  6.61 43 .06  .1  .3 BIT    2.2D  73  2 NN
2001 JUL  6 2335 49.65 38 20.62 122 37.64  6.47 28 .08  .2  .3 ROG    2.2D  67  4 AN
2001 JUL  8 2238 39.11 36 41.42 121 19.05  4.30 59 .07  .1  .3 STN    3.0D  41  3 WW
 
2001 JUL  9 0043 29.51 40 32.44 123 16.91 33.67 14 .06  .4  .9 KLA    2.4D  81 14 WW
2001 JUL  9 1408 44.35 37 28.97 118 50.44  3.47 32 .07  .3 1.2 MOR    2.6D 127  8 WW
2001 JUL  9 1549 37.32 38 48.26 122 50.39  2.53 19 .04  .2  .5 GEY    2.2D  48  4 WW
2001 JUL 10 0252 17.04 38 42.98 122 26.53  7.21 38 .15  .3  .8 GVL    2.7D  93 10 WW
2001 JUL 10 0653 23.20 36 15.24 120 24.23  7.57 39 .06  .1  .2 COA    2.2D  51  6 NN
 
2001 JUL 11 0113 14.17 38 44.76 122 26.75  6.92 21 .17  .3  .9 GVL    2.0D  45  7 WW
2001 JUL 11 1820  8.50 38 46.88 122 55.11  4.80 23 .08  .2  .7 GEY    2.0D  46  7 WW