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Rupture dynamics and ground motions from earthquakes in 2‐D heterogeneous media
Author(s) -
Bydlon Samuel A.,
Dunham Eric M.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl062982
Subject(s) - scattering , geology , spectral density , power law , hurst exponent , seismology , slip (aerodynamics) , standard deviation , fault (geology) , earthquake rupture , physics , optics , mathematics , statistics , thermodynamics
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 ∼20 km). Variations in slip and rupture velocity can arise from material heterogeneity alone but are 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 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.