HR: 1330h
AN: S12B-0387    [PDF]
TI: Activity of the Offshore Newport-Inglewood Rose Canyon Fault Zone, Coastal Southern California, From Relocated Microseismicity
AU: * Grant, L B
EM: lgrant@uci.edu
AF: Dept. Environmental Analysis and Design, University of California, Irvine, CA 92697-7070 United States
AU: Shearer, P M
EM: pshearer@ucsd.edu
AF: IGPP, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0225 United States
AB: An offshore zone of faulting approximately 10 km from the southern California coast connects the seismically active strike-slip Newport-Inglewood fault zone in the Los Angeles metropolitan region with the Holocene-age Rose Canyon fault zone in the San Diego area. Relatively little seismicity has been recorded along the offshore Newport-Inglewood Rose Canyon fault zone although it has long been suspected of being seismogenic. Active low-angle thrust faults and Quaternary folds have been imaged by seismic reflection profiling along the offshore fault zone, raising the question of whether a through-going, active strike-slip fault zone exists. We applied a waveform cross-correlation algorithm to identify clusters of microseismicity consisting of similar events. Analysis of two clusters along the offshore fault zone shows that they are associated with nearly vertical, NNW-striking faults, consistent with an offshore extension of the Newport-Inglewood and Rose Canyon strike-slip fault zones. P-wave polarities from a 1981 event cluster are consistent with a right-lateral strike-slip focal mechanism solution.
DE: 7230 Seismicity and seismotectonics
SC: Seismology [S]
MN: 2003 Fall Meeting