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Relationships among Forearc Structure, Fault Slip, and Earthquake Magnitude: Numerical Simulations with Applications to the Central Chilean Margin
  • Xiaoyu Wang,
  • Julia Morgan,
  • Nathan Bangs
Xiaoyu Wang
Rice University, Rice University

Corresponding Author:[email protected]

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Julia Morgan
Department of Earth Science, Rice University, Houston, Texas, USA, Department of Earth Science, Rice University, Houston, Texas, USA
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Nathan Bangs
University of Texas, Institute for Geophysics, Austin, TX, University of Texas, Institute for Geophysics, Austin, TX
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Abstract

Two adjacent segments of the Chile margin exhibit significant differences in earthquake magnitude and rupture extents during the 1960 Valdivia and 2010 Maule earthquakes. We use the Discrete Element Method to simulate the upper plate as having an inner and outer wedge defined by different frictional domains along the decollement. We find that outer wedge width strongly influences coseismic slip distributions. We use the published peak slip magnitudes to pick best fit slip distributions and compare our models to geophysical constraints on outer wedge widths for the margins. We obtain reasonable fits to published slip distributions for the 2010 Maule rupture. Our best-fit slip distribution for the 1960 Valdivia earthquake suggests that peak slip occurred close to the trench, differing from published models but being supported by new seismic interpretations along this margin. Finally, we also demonstrate that frictional conditions beneath the outer wedge can affect the coseismic slip distributions.