Finite Element Modeling of the Static and Quasi-static Deformation associated with the 2004 Sumatra Earthquake

Abstract

The great Sumatra-Andaman earthquake of December 26, 2004 was one of the largest earthquakes ever recorded since 1900. The earthquake resulted from complex slip on the fault along the subduction zone where the oceanic portion of the Indian Plate slides under the Eurasian Plate, by the Indonesian island of Sumatra. The direction of convergence of the subducting plate relative to the overriding plate is oriented oblique to the trench axis and the rupture occurred for 1200 km along the interplate megathrust. In the present work we use a new computational FEM strategy to model the co- and post-seismic deformation field associated with the Sumatra earthquake. We are able to study the joint effects of sphericity and 3D geometrical and reological heterogeneities on the investigated observables. The comparison between our synthetic results and the available deformation data will allow us to ascertain if complexities in the physical properties of the medium could play an important role in assessing the deformation field besides source properties.