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Rupture Dynamics and Ground Motions from Earthquakes in 2D Heterogeneous Media

Samuel A. Bydlon, & Eric M. Dunham

Published March 28, 2015, SCEC Contribution #2064

We perform 2D simulations of earthquakes on rough faults in media with random heterogeneities (with von Karman autocorrelation) to study the effects of geometric and material heterogeneity on the rupture process and resulting high-frequency ground motions in the near-fault region (out to ~20 km). Variability in slip and rupture velocity can arise from material heterogeneity alone, but is dominantly controlled by fault roughness. Scattering effects become appreciable beyond ~3 km from the fault. Near-fault scattering extends the duration of incoherent, high frequency ground motions and, at least in our 2D simulations, elevates peak and root-mean-square accelerations (i.e., Arias intensity) with negligible reduction in peak velocities. We also demonstrate that near-fault scattering typically occurs in the power-law tail of the power spectral density function, quantified by the Hurst exponent and a parameter combining standard deviation and correlation length.

Key Words
scattering, ground motion, heterogeneity, rupture dynamics, high frequency

Citation
Bydlon, S. A., & Dunham, E. M. (2015). Rupture Dynamics and Ground Motions from Earthquakes in 2D Heterogeneous Media. Geophysical Research Letters, 42(6), 1701-1709. doi: 10.1002/2014GL062982.


Related Projects & Working Groups
Ground-Motion Prediction