Next generation of deformation models for the 2004 M9 Sumatra-Andaman earthquake

The 2004 M9 Sumatra‐Andaman Earthquake (SAE) ruptured the interface separating the subducting Indo‐Australian plate from the overriding Burma plate. We construct finite element models (FEMs) that simulate deformation of the earthquake for a three‐dimensional problem domain partitioned to account for the distribution of material properties of the subducting slab, forearc, volcanic arc, and backarc. We demonstrate a protocol‐based approach for simulating coseismic deformation, in which FEMs are implemented in inverse models to estimate the fault‐slip distribution of the SAE while simultaneously honoring the geologic complexity of the subduction zone. Results suggest that deformation prediction sensitivities attributed to neglecting the different material properties of the subduction zone can be more than an order of magnitude greater than reported uncertainties for near‐field GPS measurements. The FEM‐based techniques presented here allow for geologically satisfying deformation models that will advance the reliability of modeling‐based assessments of coseismic and postseismic deformation, stress‐coupling, and tsunami genesis.