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 an earthquake of magnitude 3.4, 5 miles ENE of San Martin, CA at 12:16 AM UTC Thursday, 08 19, 2004 (05:16 PM PDT Wednesday, Aug 18, 2004).
The largest event to occur this week in this region was an earthquake of magnitude 3.4, 5 miles ENE of San Martin, CA at 12:16 AM UTC Thursday, 08 19, 2004 (05:16 PM PDT Wednesday, Aug 18, 2004).
The largest event to occur this week in this region was a microearthquake of magnitude 2.1, 10 miles WSW of Toms Place, CA at 12:17 AM UTC Monday, 08 23, 2004 (05:17 PM PDT Sunday, Aug 22, 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 AUG 19 0016 36.06 37 6.69 121 31.21 7.85 82 .06 .1 .3 CYN 3.4L 59 0 WW 2004 AUG 19 0231 2.37 36 42.97 121 22.01 2.48 75 .23 .2 .5 STN 2.9D 37 2 NN 2004 AUG 19 0305 12.92 37 6.69 121 31.26 6.93 65 .06 .1 .3 CYN 2.0D 51 1 WW 2004 AUG 19 0550 3.77 35 32.67 120 51.77 7.44 40 .05 .2 .9 SSM 2.1D 77 11 XX 2004 AUG 19 0714 59.27 40 0.08 121 3.12 9.02 37 .07 .2 .9 ALM # 3.2L 64 15 WW 2004 AUG 19 2146 55.29 35 31.38 120 49.71 3.82 48 .08 .2 1.5 SSM 2.6D 78 14 XX 2004 AUG 19 2344 15.82 35 33.15 120 48.29 5.02 39 .09 .2 .8 SSM 2.1D 68 11 XX 2004 AUG 20 0140 19.69 35 28.83 120 45.37 2.10 40 .09 .2 1.4 SSM 2.2D 73 11 XX 2004 AUG 20 0843 2.50 35 35.33 120 48.82 4.70 16 .05 .5 1.2 SSM 2.1D 95 8 XX 2004 AUG 20 1259 44.47 35 37.28 120 44.70 7.75 64 .10 .2 .6 ROB 3.0D 51 30 WW 2004 AUG 21 1619 3.21 35 37.15 120 44.41 4.09 33 .06 .3 1.3 ROB 2.2D 77 23 WW 2004 AUG 21 2203 28.61 35 42.71 120 58.15 6.85 22 .08 .4 .7 SSM 2.1D 170 9 WW 2004 AUG 22 0726 17.15 36 40.90 121 18.59 5.84 49 .05 .1 .4 STN 2.1D 33 4 WW 2004 AUG 23 0017 54.05 37 28.85 118 50.34 4.22 31 .04 .3 1.1 MOR 2.1D 171 8 WW 2004 AUG 24 0253 33.12 38 48.93 122 48.97 2.97 12 .03 .3 .5 GEY 2.1D 43 2 WW 2004 AUG 24 0536 53.88 40 53.32 123 37.44 28.36 11 .08 .5 1.2 EUR 2.5D 79 9 WW 2004 AUG 24 1903 58.17 37 21.15 121 43.27 5.90 63 .06 .1 .4 ALU 2.3D 54 11 WW 2004 AUG 25 0025 12.35 36 47.75 120 56.04 0.34 52 .14 .3 4.4 ORT 2.4D 88 11 WW 2004 AUG 25 1929 43.20 38 48.56 122 47.80 4.00 18 .04 .2 .5 GEY 2.1D 59 0 WW 2004 AUG 25 2154 45.28 36 1.16 120 40.43 1.55 9 .15 1.411.0 SLA - 2.1D 151 10 WW
