Stochastic property of fault slip distributions and statistical property of ground motion
Speaker: Yu-Sheng Sun Adviser: Chien-Chih Chen, Po-Fei Chen
Abstract
Stochastic model bases on self-similar and fractional Brownian motion (fBm) process to describe the probabilistic slip distribution on the fault surface. Scientists obtain slip distribution of an earthquake by inversion theory and wave form recorded. Stochastic model reproduces the spatial variability and the long-range spatial correlation of the slip distribution of the 1979 Imperial Valley earthquake. Authors have found that stochastic models based on non-Gaussian distributions are better suited to describe the spatial variability of the slip amplitude over the fault. The study also show that a stochastic modeling of the slip amplitude based on a Gaussian distribution fails to reproduce the spatial variability observed in the original slip distribution. They also show that both the slip distribution and the peak ground acceleration (PGA) for the 1999 Chi Chi earthquake can be described by Levy laws. Furthermore, they found that the tails of the probability density functions (PDF) characterizing the slip and the |PGA| are governed by a parameter, the Levy index, with almost the same values as predicted by the Central Limit theorem. The statistical properties of the slip spatial distribution and of the ground motions are coupled. The coupling is physically based on the principle of superposition of wave signals characterized by random amplitudes that sum according to the Central Limit theorem
References
Lavalle´e, D., and R. J. Archuleta (2003), Stochastic modeling of slip spatial complexities for the 1979 Imperial Valley, California, earthquake, Geophys. Res. Lett., 30(5), 1245, doi:10.1029/2002GL015839.
Lavallée, D., and R. J. Archuleta (2005), Coupling of the random properties of the source and the ground motion for the 1999 Chi Chi earthquake, Geophys. Res. Lett., 32, L08311, doi:10.1029/2004GL022202.