New Finite-Element Modelling of Subduction Processes in the Andes Using Realistic Geometries
The aim of this work is the better understanding of geophysical processes in subduction zones by Finite element modelling. Here we study the effects of various parameters on the deformation and stress field. The tested parameters are the friction coefficient, convergence obliquity, bending of the subduction zone, realistic geometry and visco-elasticity. Increasing the friction coefficient from 0.0 to 0.4 increases the compression by 28 %. For both friction coefficients obliquity leads to higher compression compared to straight convergence. Comparison of the model results with real topographic data reveals considerable analogies even if crustal structure is generalised. To obtain a more realistic structure for the lithosphere we adopted the geometry from well constrained density models. For these models we chose the region in the South American subduction zone around Iquique in North Chile. Including viscosity in the models has a large effect on stress and strain. In a pure elastic model stress and strain develops nearly linear. In contrast curves for the visco-elastic models show a stress maximum and a zone of maximum curvature for the strain. The stress pattern agrees well with the earthquake distribution.
KeywordsAndes Finite element Geodynamic modelling Subduction processes
This work is part of the project IMOSAGA, a cooperation with University Kiel and TU Munich within the German priority program “Mass transport and mass distribution in the system Earth” (SPP 1257). The research is supported by the German research foundation (DFG). We thank the reviewers for improving the paper by their helpful comments and recommendations.
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