October 17 was the 18th anniversary of the 6.9 magnitude Loma Prieta earthquake that struck the Bay area. But a recent story by the Bay Area’s local ABC affiliate, ABC7, chose to focus on another earthquake, a 1868 earthquake of about the same magnitude that occurred on the Hayward Fault. According to the USGS, the Hayward Fault has a return period of about 140-years and "It’s the most heavily urbanized fault in the U.S. and it’s just waiting to go off…" Next year will be the 140-th anniversary of the last earthquake on the Hayward Fault. At some point it has the potential to be a very bad earthquake there. More after the break. (Photo by sanbeiji)
The Claremont tunnel beneath the Berkeley Hills on the east side of Oakland is a water supply tunnel that serves over 800,000 customers in Richmond, Oakland, San Leandro and neighboring communities. One of the unique things about the tunnel is that it crosses the active Hayward Fault. Most of the time when you talk about designing for earthquakes youâ€™re talking about designing to withstand the seismic forces. In this case, the designers needed the water transmission tunnel to withstand up to 7.5-ft of offset due to fault slip and still maintain a minimum level of service. (Photo credit: Sue Bednarz, Jacobs Associates, Inc. by way of Civil Engineering Magazine)
This post describes the relatively recent Claremont Tunnel Seismic Upgrade Project as reported in Civil Engineering Magazine (May 2008, v. 78, no. 5, pp 58-63, 96-97).