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Sequence of Earthquakes near Berkeley, CA

Details | Ground motions | Maps | Current activity | Related links

Information from the CISN Northern California Management Center
USGS & UC Berkeley
Date & Time (Local): 2006/12/20-2007/02/23
Location: 2 mi ESE of Berkeley, CA
37.86N 122.23W
Depth (km): 8-11
Magnitude: 3.3-3.6 Mw


Beginning in late December, 2006, a sequence of earthquakes occurred near Berkeley. On December 20, at 07:12 PM (PST) a mild earthquake occured 2 miles ESE of Berkeley, CA. The moment magnitude of this earthquake was 3.6. It was followed by another Mw 3.6 quake on December 22 at 10:49 PM (PST) and a Mw 3.4 quake on December 23 at 09:21 AM (PST). The last earthquake with magnitude greater than 3 in this sequence occurred on February 23 with a moment magnitude of 3.3. This sequence of earthquakes was located along the Hayward Fault zone approximately 1 mile SE of the Berkeley campus. This is a relatively active pocket of seismicity near Berkeley's border with Piedmont.

The map below shows earthquakes along and near the Hayward Fault from 2000 to July 2007. Black dots indicate background seismicity. Other recent clusters along and near the Hayward Fault are marked in color, with the earthquakes from December 2006 in yellow.

Recent Earthquake Activity along the Hayward Fault

Bob Uhrhammer & Peggy Hellweg

Ground Motions

The CISN Northern California Management Center produces ShakeMaps for events of M3.5 and higher. ShakeMaps are based on the observed ground motions from seismic instruments combined with predicted motions in areas without sensors.

The CISN Engineering Data Center produces reports showing details of ground motions for events of interest. They have issued an Internet Data Report for the 12/20 quake showing records from various sites of interest:

These earthquake were widely felt in the East Bay. People with Internet access can report their observations of shaking and damage through the Did You Feel It? Web site. Unlike the ShakeMaps - which are based on data from seismic instruments - these maps are based on human observations. You can contribute to these data by filling out the form for the event.


Current Activity

These links will take you to seismograms showing current earthquake activity.

Related Links

The Hayward Fault

Information on the Hayward fault, including maps, tours, seismicity, and current research.

Earthquake Probabilities for the San Francisco Bay Area

Results from the USGS-led working group indicate that the San Francisco Bay Area has a 62% probability of experiencing an M6.7 or higher earthquake from 2003 to 2032.

Earthquake Scenario ShakeMaps
The USGS has computed ShakeMaps for several scenario earthquakes on the Hayward fault.

These maps illustrate the ground motions predicted for such events.

CISN Earthquake Reports

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Berkeley Seismological Lab
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Berkeley CA 94720-4760

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Last modified: Wed Aug 8 13:21:40 PDT 2007