  Santa Rosa Monterey  | |
| UTC time | 2007-10-31 03:04:54 |
|---|---|
| ISC event | 13253322 |
| USGS-ANSS | ComCat |
| Local date | October 30, 2007 (2007-10-30) |
| Local time | 20:04 PDT[1] |
| Magnitude | Mw 5.6[1] |
| Depth | 6.2 miles (10 km)[1] |
| Epicenter | 37°26′N121°46′W / 37.43°N 121.77°W /37.43; -121.77[1] |
| Fault | Calaveras Fault |
| Type | Strike-slip[1] |
| Areas affected | South Bay Northern California United States |
| Total damage | Limited[2] |
| Max. intensity | MMI VI (Strong)[3] |
| Casualties | None |
The2007 Alum Rock earthquake occurred onOctober 30 at 8:04 p.m. Pacific Daylight Time inAlum Rock Park inSan Jose, in theU.S. state ofCalifornia. It measured 5.6 on themoment magnitude scale and had a maximumMercalli intensity of VI (Strong). The event was then the largest in theSan Francisco Bay Area since the1989 Loma Prieta earthquake, which measured 6.9 on the moment magnitude scale, but was later surpassed by the2014 South Napa earthquake. Ground shaking from the Alum Rock quake reachedSan Francisco andOakland and other points further north. Sixty thousand felt reports existed far beyond Santa Rosa, as far north asEugene, Oregon.
The shock originated on theCalaveras Fault and ruptured an area of thefault for a length of about 5 km (3.1 mi) beginning at the hypocenter and extending southeast. There was no evidence of anysurface rupture along the fault caused by theearthquake.[4] David Oppenheimer, aseismologist at theUnited 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 nearbyHayward Fault.[5]
Intensity VI (Strong) effects included broken windows and items that were knocked off store shelves, but the event caused no serious damage or injuries. Some parts of theBay Area felt the rupture for up to 15 seconds.[5]
ElarmS, an earthquake early warning system, accurately predicted the quake seconds before it struck, correctly estimating the earthquake'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.[6]
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