HR: 1340h
AN: S23A-1102    [Abstracts]
TI: Locating Microseism Sources in Offshore Southern California
AU: * Tian, X
EM: xytian@gps.caltech.edu
AF: California Institute of Technology, 1200 E California Blvd 252-21, Pasadena, CA 91125, United States
AU: Clayton, R W
EM: clay@gps.caltech.edu
AF: California Institute of Technology, 1200 E California Blvd 252-21, Pasadena, CA 91125, United States
AB: We use the broadband stations from the S. California network to locate the apparent origin of secondary microseisms energy (5-8 Hz band). The procedure is to grid the offshore region and using each grid point as the source point, predict the response of a Rayleigh wave at each station. These predicted waveforms are then correlated with the data over a time window that is typically a 1/2 hour in length and composited at the grid point. The length of the time window controls a tradeoff between the spatial-temporal resolution of the sources and the robustness on the image. The procedure is valid for multiple sources. This results show that during periods of high microseism activity the sources are distinct at several locations in a region approximately 50-100 km offshore. For an 11/09/2002 Southern Ocean storm, for example, two zones parallel to each other and perpendicular to the coast are imaged.
DE: 3025 Marine seismics (0935, 7294)
DE: 7255 Surface waves and free oscillations
SC: Seismology [S]
MN: 2007 Fall Meeting