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 light earthquake of magnitude 4.2, 2 miles ESE of The Geysers, CA at 05:27 PM UTC Sunday, 01 04, 2009 (09:27 AM PST Sunday, Jan 04, 2009).
The largest event to occur this week in this region was a microearthquake of magnitude 1.9, 3 miles SSW of Gilroy, CA at 05:04 PM UTC Tuesday, 01 06, 2009 (09:04 AM PST Tuesday, Jan 06, 2009).
The largest event to occur this week in this region was an earthquake of magnitude 1.9, 5 miles ENE of Mammoth Lakes, CA at 05:34 PM UTC Monday, 01 05, 2009 (09:34 AM PST Monday, Jan 05, 2009).
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 2009 JAN 1 0242 1.03 36 40.61 121 18.17 5.28 56 .05 .1 .3 2.0D 36 3 2009 JAN 1 0608 18.17 39 26.30 123 6.17 5.11 30 .07 .2 .8 2.4D 42 16 2009 JAN 3 1332 51.34 38 50.24 122 49.60 2.49 48 .07 .1 .3 2.2D 38 2 2009 JAN 3 1437 59.04 38 49.33 122 46.73 0.90 44 .15 .2 .3 2.0D 37 1 2009 JAN 4 1727 10.48 38 46.94 122 46.35 4.68 66 .08 .1 .2 4.2W 25 1 2009 JAN 4 1733 3.93 38 47.79 122 44.40 0.97 49 .08 .1 .2 2.1D 48 2 2009 JAN 5 0420 47.26 38 49.35 122 48.09 3.41 64 .07 .1 .2 2.4D 26 2 2009 JAN 5 1446 55.40 36 31.91 121 6.75 8.89 64 .06 .1 .2 2.3D 45 4 2009 JAN 5 1601 53.94 36 31.87 121 6.89 8.27 43 .06 .2 .3 2.1D 71 4 2009 JAN 6 0838 22.12 38 54.87 123 2.40 0.29 45 .06 .1 1.3 2.5D 37 9 2009 JAN 6 1218 50.83 36 20.65 120 55.00 4.45 74 .10 .1 .4 2.8D 52 3 2009 JAN 6 2102 22.46 38 49.74 122 47.79 2.15 68 .06 .1 .2 2.9L 31 1 2009 JAN 7 2031 41.78 38 50.49 122 49.44 1.53 39 .09 .2 .4 2.0D 38 3
