HR: 13:55h
AN: S43D-02    [Abstracts]
TI: Spatial and Temporal Length Scales Characterizing the Evolution of Seismicity Rates.
AU: * Levin, S Z
EM: slevin2@uwo.ca
AF: University of Western Ontario, Department of Earth Sciences Bio. and Geol. Sciences Bldg., London, ON N6A 5B7 Canada
AU: Tiampo, K F
EM: ktiampo@uwo.ca
AF: University of Western Ontario, Department of Earth Sciences Bio. and Geol. Sciences Bldg., London, ON N6A 5B7 Canada
AU: Bowman, D D
EM: dbowman@fullerton.edu
AF: California State University, Fullerton, Dept. of Geological Sciences , Fullerton, CA 92834-6850 United States
AB: Numerous studies have documented systematic changes in seismicity rates preceding large magnitude events. Many works suggest that these changes can be used to conduct time-dependent earthquake forecasting. We use two approaches to examine the spatial and temporal scales characterizing the seismicity rate changes, with the goal of exploring the underlying physical process. The first set of analyses follow the methodology outlined in Tiampo et al. [2002], for determining the eigenfunctions describing spatial and temporal correlation in regional seismicity. We extend the method by incorporating a temporal lag in construction of the covariance matrix. Decomposing the matrix into its eigenmodes then highlights correlated activity separated in time by the specified lag. Here, we present the results obtained for southern California seismicity from 1932 to 2004, using a range of temporal lags. Our second approach considers changes in yearly seismicity rates as a function of distance from the rupture plane of major historical events. To quantify the significance of trends in the seismicity rates, we auto-correlate the data, using a range of spatial and temporal lags. Here, we focus on the results for the 1987 Superstition Hills, 1992 Landers, and 1994 Northridge, California, earthquakes. We also briefly address the results for the 1971 San Fernando, 1983 Coalinga, 1986 Chalfant Valley, 1989 Loma Prieta, 1999 Hector Mine events and the 2002 Denali, AK, earthquake.
DE: 4460 Pattern formation
DE: 4475 Scaling: spatial and temporal (1872, 3270, 4277)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
SC: Seismology [S]
MN: Fall Meeting 2005