HR: 0800h
AN: S51B-0150    [Abstracts]
TI: Seismic Noise Correlation with Seismicity and Fluid Flow
AU: * Dorman, L M
EM: ldorman@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, La Jolla, CA 92093-0220 United States
AU: DeShon, H R
EM: hdeshon@emerald.ucsc.edu
AF: Earth Sciences Department, University of California, Santa Cruz, 1156 High St., Santa Cruz, CA 95064 United States
AU: Brown, K
EM: kmbrown@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, La Jolla, CA 92093-0220 United States
AU: Schwartz, S
EM: sschwartz@ucsc.earthsci.ucsd.edu
AF: Earth Sciences Department, University of California, Santa Cruz, 1156 High St., Santa Cruz, CA 95064 United States
AU: Tryon, M
EM: mtryon@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD, 9500 Gilman Drive, La Jolla, CA 92093-0220 United States
AB: During the Costa Rica Seismic Zone Experiment (CRSEIZE), we observed intriguing correlations between earthquake activity, seismic noise observed on the seafloor, and fluid flow through the seafloor (K. M. Brown and others, this meeting). These correlations are observed on instruments separated by as much as 30 kilometers. Here we describe the nature of the noise, the temporal patterns, and speculate about the transmission mechanism and the source(s). Seismic noise on the seafloor is strongly influenced by ocean wave activity, so we first compare the temporal variations in noise with the ocean wave field as computed from the global wind field by Tolman. This comparison shows that the long-term (months) pattern of wave data provides a baseline for the the seismic noise field, but does not predict the shorter (days) impulsive noise anomalies which correlate with variations in fluid flow. At some sites, the noise shows spectral peaks which have been explained as peaks in the mode Q of Scholte waves (Schreiner and Dorman) and shear resonances (Godin and Chapman). The frequencies of these peaks is controlled by the shear velocity structure and the frequencies themselves provide earth data constraining the seafloor velocity structure.
DE: 7209 Earthquake dynamics and mechanics
SC: Seismology [S]
MN: 2004 AGU Fall Meeting