Rupture dynamics and ground motions from earthquakes in 2-D heterogeneous media
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Abstract©2015. American Geophysical Union. All Rights Reserved. We perform 2-D simulations of earthquakes on rough faults in media with random heterogeneities (with von Karman distribution) 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 ∼20km). Variations in slip and rupture velocity can arise from material heterogeneity alone but are dominantly controlled by fault roughness. Scattering effects become appreciable beyond ∼3km from the fault. Near-fault scattering extends the duration of incoherent, high-frequency ground motions and, at least in our 2-D simulations, elevates 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 another parameter combining standard deviation and correlation length. Key Points Fault roughness, not material heterogeneity, dominates rupture process Introduce parameter that can be used to quantify near-fault scattering Scattering affects the duration and amplitude of high-frequency ground motions
CitationBydlon SA, Dunham EM (2015) Rupture dynamics and ground motions from earthquakes in 2-D heterogeneous media. Geophysical Research Letters 42: 1701–1709. Available: http://dx.doi.org/10.1002/2014gl062982.
SponsorsThis work was supported by the National Science Foundation (ACI-1148493), King Abdullah University of Science and Technology (KAUST) through a joint KAUST Academic Excellence Alliance (AEA) grant with Stanford, and the Southern California Earthquake Center. SCEC is funded by NSF Cooperative Agreement EAR-1033462 and USGS Cooperative Agreement G12AC20038. The SCEC contribution for this paper is 2064. We are grateful to Jeremy Kozdon for his assistance in extending the numerical method to heterogeneous media.
JournalGeophysical Research Letters