HR: 14:55h
AN: T12E-05    [PDF]
TI: Long-term Creep Behavior (1928-2002) of the Hayward Fault at Depth in the Claremont Water Tunnel, Berkeley, CA
AU: * Cain, W J
EM: bcain@ebmud.com
AF: East Bay Municipal Utility District Seismic Improvement Program, 375 Eleventh St MS SIP, Oakland, CA 94607-4240 United States
AU: Hampton, J L
EM: jlhampto@ebmud.com
AF: East Bay Municipal Utility District Survey Section, P.O. Box 24055, Oakland, CA 94623-1055 United States
AB: The Claremont Tunnel, a nine foot horseshoe shaped water tunnel conveying up to 175 million gallons per day (mgd) of treated drinking water to 800,000 residents on the east side of San Francisco Bay, crosses the Hayward Fault approximately 850 feet from the west portal of the tunnel. Creep along the fault has offset the tunnel at a depth of about 130 feet below the ground surface. Completed in 1928, the tunnel has undergone two inspections (1966 and 2002) in which detailed survey measurements have been made of the creep movements of the fault. There have been few opportunities to secure creep measurements below the ground surface. This paper will present the results of the two surveys showing the creep that has occurred at a depth of 130 feet and give time-based creep rates based on survey measurements. It will compare these measured creep rates with the tectonic creep model developed by NOAA. Due to the large time interval between the two surveys, surveying technology has dramatically changed. A discussion of the techniques used in each survey will be presented with discussions of how current technology compares with historical methods and what impact this has on the results.
DE: 7221 Paleoseismology
DE: 7230 Seismicity and seismotectonics
DE: 8123 Dynamics, seismotectonics
DE: 8159 Rheology--crust and lithosphere
DE: 8164 Stresses--crust and lithosphere
SC: Tectonophysics [T]
MN: 2003 Fall Meeting