2007 Alum Rock earthquake 2007 Alum Rock earthquake The 2007 Alum Rock earthquake occurred on in Alum Rock Park in San Jose, California. It measured 5.6 on the moment magnitude scale and had a maximum Mercalli intensity of VI ("Strong"). The event was then the largest in the San Francisco Bay Area since the 1989 Loma Prieta earthquake, which measured 6.9 on the moment magnitude scale, but was later surpassed by the 2014 South Napa earthquake. Ground shaking from the Alum Rock quake reached San Francisco and Oakland and other points further north. Sixty thousand felt reports existed far beyond Santa Rosa, as far
1989 Loma Prieta earthquake the San Juan Bautista segment, or an M7 event on the San Francisco Peninsula segment, United States Geological Survey (USGS) seismologist Allan Lindh's 1983 forecasted rupture length of (starting near Pajaro Gap, and continuing to the northwest) for the San Juan Bautista segment nearly matched the actual rupture length of the 1989 event. An updated forecast was presented in 1988, at which time Lindh took the opportunity to assign a new name to the San Juan Bautista segment – the Loma Prieta segment. In early 1988, the Working Group for California Earthquake Probabilities (WGCEP) made several statements regarding their forecasts