HR: 14:25h
AN: S53C-04    [Abstracts]
TI: Resolution Analysis of finite fault inversions: A back-projection approach.
AU: * Ji, C
EM: ji@geol.ucsb.edu
AF: University of California, 1006 Webb Hall UCSB, Santa Barbara, CA 93106,
AU: Shao, G
EM: shao@umail.ucsb.edu
AF: University of California, 1006 Webb Hall UCSB, Santa Barbara, CA 93106,
AB: The resolution of inverted source models of large earthquakes is controlled by frequency contents of \"coherent\" (or \"useful\") seismic observations and their spatial distribution. But it is difficult to distinguish whether some features consistent during different inversions are really required by data or a consequence of "prior" information, such as velocity structures, fault geometry, model parameterizations. Here, we investigate the model spatial resolution by first back projecting and stacking the data at the source regions and then analyzing the spatial- temporal variations of the focusing regions, which arbitrarily defined as the regions with 90% of the peak focusing amplitude. Our preliminary results indicated 1) The spatial-temporal resolution at a particularly direction is controlled by the region of directivity parameter [pcos(θ)] within the seismic network, where p is the horizontal slowness from the hypocenter and θ is the difference between the station azimuth and this orientation. Therefore, the network aperture is more important than the number of stations. 2) Simple stacking method is a robust method to capture the asperities but the sizes of focusing regions are usually much larger than what data could resolve. By carefully weighting the data before the stacking could enhance the spatial resolution in a particular direction. 3) The results based on the teleseismic P waves of a local network usually surfers the trade-off between the source's spatial location and its rupture time. The resolution of the 2001 Kunlunshan earthquake and 2006 Kuril island earthquake will be investigated.
DE: 7200 SEISMOLOGY
SC: Seismology [S]
MN: 2007 Fall Meeting