HR: 14:10h
AN: NG32A-03 INVITED     [PDF]
TI: Characterization of space-time correlations in aftershock and seismicity patterns
AU: * Shcherbakov, R
EM: roshch@physics.ucdavis.edu
AF: Center for Comp. Sci. and Eng., University of California, Davis, CA 95616 United States
AU: Turcotte, D L
EM: turcotte@geology.ucdavis.edu
AF: Department of Geology, University of California, Davis, CA 95616 United States
AU: Rundle, J B
EM: jbrundle@ucdavis.edu
AF: Center for Comp. Sci. and Eng., University of California, Davis, CA 95616 United States
AB: Correlations in space and time play a fundamental role in earthquake processes. The direct manifestation of the effects of correlations is the occurrence of aftershocks due to the stress transfer in the vicinity of the main shock. Less obvious and more debatable changes in correlations might occur in the background seismicity before large earthquakes. Using statistical physics it is possible to introduce a measure of spatial correlations through the correlation length. This quantity characterizes how local fluctuations in space can influence the occurrence of earthquakes over distances comparable with the value of the correlation length in a seismogenic region. Partial information of correlations is also present in the well-known Gutenberg-Richter frequency-magnitude statistics which is reflected in the change of the shape of the distribution during different time periods. Time correlations are well documented for aftershock sequences and described by the modified Omori's law. This law specifies a temporal decay of aftershocks and has power-law scaling. The physical basis of these laws will be discussed in the context of correlations. In addition we have obtained scaling laws for the spatial clustering of aftershocks using pair and density correlation functions and a radius of gyration. We have also obtained the variations in time of the correlation function and correlation length associated with the spatial and temporal processes in seismogenic regions. Applications of the correlation analysis to background seismicity will also be discussed.
DE: 3220 Nonlinear dynamics
DE: 7200 SEISMOLOGY
DE: 7209 Earthquake dynamics and mechanics
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
SC: Nonlinear Geophysics [NG]
MN: 2003 Fall Meeting