From Wikipedia, the free encyclopedia
The 2007 Alum Rock earthquake occurred on
October 30, 2007 at approximately 8:04 p.m. PDT
(October 31, 3:04 a.m. UTC)[1] in the
San
Jose area in California. It measured 5.6 on the moment magnitude scale and had a
depth of 5.7 miles (9.2 km).[2]
The Alum Rock earthquake was the largest in the San
Francisco Bay Area since the 1989 Loma Prieta
earthquake, which measured 6.9 on the moment magnitude scale.
Ground shaking from the Alum Rock quake reached San Francisco and Oakland
and other points further north. ElarmS, an earthquake early warning
system, accurately predicted the quake seconds before it struck,
correctly estimating the quake's magnitude to within
0.5 magnitude units using only three to four seconds worth of
data. Scientists with the California Integrated Seismic Network
hope to refine the system to provide a 10-second warning in a
similar quake to residents of Oakland and San Francisco.[3]
Geology
The quake occurred about 8–9 kilometers (about 5 miles)
underground on the Calaveras Fault. The event caused
moderate shaking in the epicentral region with over 60,000 felt
reports, existing far beyond Santa Rosa. Based on the distance
between aftershocks to
the hypocenter, focal
mechanisms, and moment tensor solutions, the earthquake
ruptured an area of the fault for a length of about 5 km
(3 miles), starting at the hypocenter and extending southeast.
However, scientists found no surface trace of the earthquake along
the fault.[4]
Damage
The earthquake caused minor damage, such as knocking things off
of shelves, but caused no casualties. The shaking was felt as far
north as Eugene,
Oregon. Some parts of the area felt the rupture for up to
15 seconds. David Oppenheimer, a seismologist at the United States Geological
Survey (USGS), said that although the quake was felt as a
strong jolt over a wide region, it was more significant because it
caused stress changes in the Calaveras Fault and the nearby Hayward Fault.[5]
See also
References
| Significant California
earthquakes |
|
Very Large
(7.0 or greater) |
|
|
Large
(6.0-6.9) |
|
|
Moderate
(less than 6.0) |
|
|
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