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ShakeOut Scenario Update 3
Mw 7.8 Earthquake Scenario
11:35:30AM 11/13/08
Report by the California Integrated Seismic Network (Caltech/USGS) Kate Hutton, Seismological Laboratory, Caltech
11:35AM - 11/13/08
Both NEIC and SCSN agree on a magnitude 7.8Mw (moment magnitude). The aftershock distribution indicates a San Andreas fault rupture from Bombay Beach (east of the Salton Sea), to approximately Palmdale. Shaking was very strong over the entire metropolitan area (see the ShakeMap image below).
The last comparable earthquake in this region occurred on January 9th, 1857 (Palmdale segment of the San Andreas Fault), and sometime in 1680 (Coachella Valley segment).
The image below is the ShakeMap for the M7.0 afterhsock, which occurred at 10:33AM 11/13/08:
10:35AM - 11/13/08
There has been a major aftershock in the Imperial Valley. The preliminary magnitude is Mw7.0. Further details will be released when they become available.
10:30AM - 11/13/08
An improved epicentral determination shows that the earthquake started near Bombay Beach, CA, east of the Salton Sea. The moment tensor solution shows right-lateral strike-slip motion, consistent with a rupture on the southern portion of the San Andreas Fault. Aftershocks are being recorded as far north as the San Bernardino and Palmdale areas, indicating that the rupture is at least 200 km (~125 miles) long.
The image below shows the preliminary ShakeMap for the mainshock, indicating strong shaking throughout many areas of Southern California. Areas in orange and red may have experienced significant damage.
The following are a series of images from the ShakeMovie, showing wave propagation through Southern California:
The following is an automatic real-time moment tensor solution report from the Caltech/USGS Southern California Seismic Network:
SHAKEOUT SCENARIO:
** SCSN Moment Tensor Solution Message **
REAL-TIME SOLUTION: NOT REVIEWED
Inversion Method: Complete Waveform
Number of Stations used: 5
Stations: CI.BC3 CI.BLY CI.BAR CI.WSS CI.EDW2
Real-Time Solution:
-------------------
Event ID : 999
Magnitude : 6.7
Depth (km) : 8.5
Origin Time : 11/13/2008 18:00:00:00
Latitude : 33.42
Longitude : -115.84
Further Information at: http://www.usgs.gov/homepage/science_features/shakeout.asp
Lower Hemisphere Equiangle Projection
============= Station Information ==============
Name Distance Azimuth VR ZCore
-------------------------------------------------
CI.BC3 78.481 32.638 54.886 17.00
CI.BLY 149.957 58.925 53.834 26.00
CI.BAR 82.836 239.638 4.368 17.00
CI.WSS 282.531 296.620 40.300 46.00
CI.EDW2 279.052 316.938 58.072 44.00