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
Information about seismicity for other regions is available from the U.S. Geological Survey Earthquake Hazards Program Website. 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 provided at the Northern California Maps of Recent Earthquake Activity website. 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
The largest event to occur this week in this region was a minor earthquake of magnitude 3.9, 3 miles SSW of Gilroy, CA at 07:55 PM UTC Monday, 10 25, 2004 (12:55 PM PDT Monday, Oct 25, 2004).
This event produced light shaking in the epicentral area with weak shaking reported as far as San Francisco to the north and Big Sur to the south. It occurred on or near the Castro fault, a minor fault that parallels the Sargent fault, in much the same location as a M4.9 event that occurred on May 13, 2002. For more information about the 2002 event, check out the following URL: http://earthquake.usgs.gov/eqinthenews/2002/nc40133364/
The largest event to occur this week in this region was a minor earthquake of magnitude 3.9, 3 miles SSW of Gilroy, CA at 07:55 PM UTC Monday, 10 25, 2004 (12:55 PM PDT Monday, Oct 25, 2004).
The largest event to occur this week in this region was a microearthquake of magnitude 2.3, 10 miles WSW of Toms Place, CA at 02:01 PM UTC Tuesday, 10 26, 2004 (07:01 AM PDT Tuesday, Oct 26, 2004).
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 2004 OCT 21 0151 1.00 35 51.17 120 24.19 5.91 43 .18 .3 .4 GOL 2.5D 55 2 WW 2004 OCT 21 0152 36.58 35 51.54 120 24.23 5.33 39 .13 .3 .4 GOL 2.4D 55 3 WW 2004 OCT 21 0738 43.02 36 14.48 120 48.13 6.92 58 .07 .2 .3 BIT 2.8D 67 3 XN 2004 OCT 21 1151 54.54 39 35.86 121 53.73 25.64 9 .09 1.0 1.4 SAC 2.3D 208 25 WW 2004 OCT 21 2214 34.62 38 46.24 122 43.86 0.75 32 .09 .2 .7 GEY 3.0L 102 7 WW 2004 OCT 22 0526 59.11 38 49.09 122 47.50 4.65 27 .04 .2 .3 GEY 2.5D 75 1 WW 2004 OCT 22 0752 7.71 35 56.05 120 29.19 5.56 37 .08 .2 .2 MID 2.4D 54 3 WW 2004 OCT 22 1422 16.74 38 46.40 122 44.68 1.22 16 .03 .2 .7 GEY 2.1D 49 6 WW 2004 OCT 23 0344 41.75 35 54.57 120 27.19 6.47 44 .08 .2 .3 GOL 2.7D 47 4 WW 2004 OCT 23 0418 8.58 35 56.15 120 29.99 14.51 29 .10 .3 .4 MID 2.0D 53 1 WW 2004 OCT 23 0449 45.32 35 52.30 120 26.40 10.53 33 .13 .4 .5 GOL 2.1D 59 4 WW 2004 OCT 23 0514 10.60 39 40.00 122 55.59 4.02 18 .46 .932.8 BAR - 2.3D 85 18 WW 2004 OCT 23 0638 0.87 35 42.01 120 57.75 4.80 8 .03 3.6 6.6 SSM - 2.0D 223 11 WW 2004 OCT 23 0755 17.79 35 52.96 120 25.68 6.20 50 .10 .2 .3 GOL 2.9D 38 2 WW 2004 OCT 23 1302 21.30 35 34.78 120 50.14 0.02 40 .29 .7 5.3 SSM # 2.5D 142 24 WW 2004 OCT 23 1344 59.93 36 39.50 121 16.50 3.24 48 .06 .1 .3 STN 2.4D 54 1 WW 2004 OCT 23 1416 34.80 36 39.62 121 16.51 3.74 56 .06 .1 .3 STN 3.1L 40 1 WW 2004 OCT 23 1524 59.22 35 48.14 121 3.23 2.90 24 .28 .9 3.9 SSM 2.3D 174 13 WW 2004 OCT 23 1553 8.16 40 58.71 123 31.28 26.19 10 .12 .7 2.2 KLA 2.5D 110 21 WW 2004 OCT 23 1611 7.64 35 53.69 120 26.42 5.27 36 .10 .3 .4 GOL 2.3D 48 4 WW 2004 OCT 23 2127 0.11 38 46.24 122 44.19 1.57 14 .04 .3 .9 GEY 2.0D 77 7 WW 2004 OCT 24 0247 3.37 38 46.31 122 44.58 0.47 36 .15 .2 .8 GEY 3.4L 44 6 WW 2004 OCT 24 0341 16.26 35 55.51 120 28.44 9.55 47 .08 .2 .3 MID 2.8D 40 4 WW 2004 OCT 24 1805 39.23 35 57.65 120 30.88 5.44 36 .06 .2 .2 MID 2.2D 61 2 WW 2004 OCT 25 0211 19.37 40 49.87 123 22.76 24.82 15 .09 .4 1.1 KLA 2.0D 73 23 WW 2004 OCT 25 1955 37.64 36 57.97 121 35.87 7.68 90 .18 .2 .5 SAR 3.9L 23 2 WW 2004 OCT 26 1306 36.13 35 46.44 120 18.47 4.77 30 .16 .4 .5 GOL 2.3D 92 2 WW 2004 OCT 26 1319 13.08 35 44.82 121 21.44 0.06 33 .23 1.3 2.7 SSM # 2.4D 193 29 WW 2004 OCT 26 1401 6.30 37 29.31 118 50.70 8.43 32 .03 .2 .8 MOR 2.3D 125 8 WW 2004 OCT 26 1418 36.33 40 18.74 121 31.42 9.73 12 .04 .7 1.6 ALM 2.3D 114 17 WW 2004 OCT 26 1804 56.42 35 41.21 121 1.08 3.15 42 .15 1.0 .9 SSM 2.8D 217 16 WW 2004 OCT 27 1332 32.64 35 53.28 121 17.56 0.31 16 .34 2.5 7.5 SSM # 2.0D 208 23 WW 2004 OCT 27 2120 29.62 37 3.63 120 38.82 11.33 15 .37 3.6 4.8 JQN 2.2L 132 64 WW
