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@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
The largest event to occur this week in this region was a minor earthquake of magnitude 3.5, 2 miles NNE of The Geysers, CA at 01:39 PM UTC Sunday, 12 05, 1999 (05:39 AM PST Sunday, Dec 05, 1999).
The largest event to occur this week in this region was a microearthquake of magnitude 2.6, 2 miles SW of San Juan Bautista, CA at 12:26 PM UTC Wednesday, 12 08, 1999 (04:26 AM PST Wednesday, Dec 08, 1999).
The largest event to occur this week in this region was a microearthquake of magnitude 2.1, 10 miles SW of Toms Place, CA at 10:45 PM UTC Wednesday, 12 08, 1999 (02:45 PM PST Wednesday, Dec 08, 1999).
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 1999 DEC 2 0234 41.20 36 39.14 121 16.00 3.79 54 .08 .1 .3 STN 2.9D 40 2 NN 1999 DEC 2 0323 1.53 36 39.26 121 16.18 3.85 57 .09 .1 .3 STN 3.1D 40 1 NN 1999 DEC 2 1918 15.30 37 20.06 121 42.12 7.81 81 .07 .1 .3 SFL 2.2D 38 6 NN 1999 DEC 3 0506 21.95 40 30.17 124 13.89 26.96 12 .05 .6 1.0 EUR 2.6D 121 9 NN 1999 DEC 3 0528 31.02 37 20.08 121 42.17 7.54 76 .04 .1 .2 SFL 2.0D 59 6 NN 1999 DEC 4 1037 23.52 37 39.98 122 3.60 6.91 75 .09 .1 .3 HAY 2.4D 32 5 NN 1999 DEC 4 1430 0.68 37 39.21 119 25.07 6.99 36 .43 .719.6 KAI # 2.0D 78 30 NN 1999 DEC 5 1259 31.80 39 42.46 123 38.16 6.26 18 .06 .3 .3 MAA 2.3D 169 5 NN 1999 DEC 5 1334 48.19 38 49.18 122 47.36 1.52 34 .04 .1 .2 GEY 2.5D 39 1 NN 1999 DEC 5 1335 25.37 38 49.31 122 47.41 1.52 29 .05 .2 .3 GEY 2.4D 39 2 NN 1999 DEC 5 1339 3.46 38 49.42 122 47.31 3.52 46 .09 .1 .5 GEY 3.5D 38 2 NN 1999 DEC 5 1517 13.01 38 48.09 122 47.42 0.67 24 .04 .1 .2 GEY 2.2D 37 1 NN 1999 DEC 5 2321 26.84 39 41.96 123 29.90 8.97 18 .04 .2 .5 MAA 2.5D 73 7 NN 1999 DEC 7 0400 3.30 40 21.45 124 15.92 31.08 13 .07 .8 1.2 MEN 2.2D 178 14 NN 1999 DEC 7 0753 9.09 38 46.60 122 44.67 4.10 39 .06 .1 .3 GEY 2.6D 33 2 NN 1999 DEC 7 0825 19.89 38 48.89 122 49.98 1.26 16 .04 .2 .5 GEY 2.0D 50 3 WW 1999 DEC 7 0844 41.02 37 8.28 119 47.73 22.03 9 .01 1.0 .3 KAI 2.3D 123 9 NN 1999 DEC 7 1528 54.04 38 46.32 122 44.63 3.76 36 .06 .1 .3 GEY 2.6D 33 2 NN 1999 DEC 8 0155 18.25 36 32.38 121 7.78 8.47 34 .05 .2 .4 PIN 2.0D 58 6 WW 1999 DEC 8 1226 14.24 36 49.77 121 33.56 6.55 60 .11 .2 .3 SJB 2.6D 30 2 WW 1999 DEC 8 1448 0.53 40 45.30 124 24.27 22.22 30 .06 .5 .7 EUR 3.2L 211 32 WW 1999 DEC 8 1849 27.08 37 33.86 121 56.76 21.84 12 .43 8.2 4.6 HAY 2.4D 152 12 WW 1999 DEC 8 2245 19.26 37 28.29 118 49.70 5.73 27 .06 .4 .7 MOR 2.1D 149 8 WW
