Impact of megathrust geometry on inversion of coseismic slip fromgeodetic data: Application to the 1960 Chile earthquake

摘要

We analyze the role of megathrust geometry on slipestimation using the 1960 Chile earthquake (Mw = 9.5) asan example. A variable slip distribution for this earthquakehas been derived by Barrientos and Ward (1990) applyingan elastic dislocation model with a planar fault geometry.Their model shows slip patches at 80-110 km depth,isolated from the seismogenic zone, interpreted as aseismicslip. We invert the same geodetic data set using a finiteelement model (FEM) with precise geometry derived fromgeophysical data. Isoparametric FEM is implemented toconstrain the slip distribution of curve-shaped elements.Slip resolved by our precise geometry model is limited tothe shallow region of the plate interface suggesting that thedeep patches of moment were most likely an artifact of theplanar geometry. Our study emphasizes the importance offault geometry on slip estimation of large earthquakes.