HR: 0800h
AN: NG31A-0862    [Abstracts]
TI: Aftershocks In Massless Cellular Automaton Slider-Block Models.
AU: * Morein, G
EM: gleb@cse.ucdavis.edu
AF: Center for Computational Science and Engineering, University of California One Shields Avenue, Davis, CA 95616
AU: Rundle, J
EM: jbrundle@ucdavis.edu
AF: Center for Computational Science and Engineering, University of California One Shields Avenue, Davis, CA 95616
AU: Turcotte, D L
EM: turcotte@geology.ucdavis.edu
AF: Department of Geology, University of California One Shields Avenue, Davis, CA 95616
AB: We present preliminary results for a modified Rundle-Jackson-Brown model that generates clusters of aftershocks. The model is represented by the two-dimensional array of massless blocks connected by springs to its neighbors and the loader plate. Stress is introduced to the system by moving the loader plate with infinitesimally low velocity and stress is dissipated by the toppling sites. The residual value of the toppled site is a random variable with prescribed noise amplitude. We study the system with different ranges of interaction. Our goal is to observe Omori-type laws for aftershocks under the condition that statistics of all events still obey the Gutenberg-Richter law. In addition, we are looking for aftershock time sequences that are not induced by the loader plate motion; that is, they are present in the model for a non-moving loader plate. We also observe that, for systems with a large range of interaction (called near mean-field systems), the frequency-size statistics exponent changes from the expected 1.5 to a somewhat larger value. The distribution of inter event times is also studied and shown to obey a power-law decay.
DE: 7260 Theory and modeling
DE: 3210 Modeling
DE: 3220 Nonlinear dynamics
DE: 3240 Chaos
SC: Nonlinear Geophysics [NG]
MN: 2004 AGU Fall Meeting