Map
of California & Nevada earthquakes
M3.9 near Berkeley, CA
Details | Ground motions | Maps | Waveforms | Related links
| Information from the CISN Northern California Management Center USGS & UC Berkeley |
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| Date & Time (Local): | 2003/09/04 18:39:54 (PST) |
| Date & Time (UTC): | 2003/09/05 01:39:54 (UTC) |
| Location: | 3 miles SE of Berkeley, CA 37.845N 122.222W |
| Depth (km): | 12.4 |
| Magnitude: | 3.9 Mw |
- Details
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A M3.9 earthquake rattled the East Bay on Thursday, Sept 4th at 6:39 PM local time. The earthquake was centered near the Piedmont area of Oakland. It was followed by an M3.0 aftershock at 07:43 PM. In 1986, a M4.0 event occurred in a very similar location. Further north, the El Cerrito/Kensington area has experienced an M4.1 event in 1998 and an M4.2 event in 1994.
The earthquake occurred in the Hayward Fault zone, approximately 6 km SE of the Berkeley campus. It had three small (M<0) foreshocks and 50+ aftershocks (-0.8<=M<=3.0) in the first 18 hours of the UTC day. These events were too small to be detected by the automatic processing systems and were identified by visually scanning the vertical component geophone record from the northern Hayward Fault Network borehole station BRIB.
Bob Uhrhammer & Lind Gee
- Ground Motions
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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 Quick Report (IQR) for the M3.9 showing records from Piedmont Junior High School (2.9 km away) as well as other sites of interest:
This earthquake was 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.
- Maps
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- RecentEQs quad for this event
- Bay Area seismicity ( Current (through last week) | Previous annual maps )
- Waveforms
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These links will take you to seismocams showing current earthquake activity.
Below are links to waveforms for the 3.9 Mw event.
- CISN Waveforms
- A comparison of the waveforms from the two largest events and a small event (the M -0.7 @ 01:53:52), 4-24 Hz band pass filtered, is shown in the attached gif plot of the BRIB vertical component geophone record.
- BSL Seismogram from BKS via "Make Your Own Seismogram" showing the M3.9 Mw.
- Related Links
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- The Hayward Fault
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Information on the Hayward fault, including maps, tours, seismicity, and current research.
- Earthquake Probabilities for the San Francisco Bay Area
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New 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
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The USGS has computed ShakeMaps for several scenario earthquakes on the
Hayward fault.
- M6.5 on the northern Hayward fault
- M6.7 on the southern Hayward fault
- M6.9 on the full Hayward fault
These maps illustrate the ground motions predicted for such events.
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Berkeley Seismological Lab
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Last modified: Wed Aug 8 13:21:40 PDT 2007