Accretionary wedge and oceanic crust thickness effect on surface deformation: Study case the Mentawai segment

Abstract

Southern Sumatra forearc is classified as a compressional accretionary type. The existence of the accretionary wedge has a significant role in sediment deformation. This sediment deformation may contribute to generating higher tsunami generation. A two-dimensional crustal deformation modeling was performed to analyze the influence of the accretionary wedge. Furthermore, oceanic crust thickness variations are also simulated in this modeling as the incoming plate’s role in surface deformation is poorly understood. The crustal deformation modeling consists of two types of earthquake period: interseismic period and coseismic period. Various geometry features were applied for each earthquake period. The crustal deformation modeling itself is based on the finite element method. The result shows that there are different effects on the geometrical model being used. The pattern and amount of surface deformation also depend on at which the fault is activated. Extended geometry models such as three-dimensional modeling will be required for further study.