A spatial random field model to characterize comlexity in earthquake slip

Paul Mai*, Gregory C. Beroza

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

427 Scopus citations


Finite-fault source inversions reveal the spatial complexity of earthquake slip over the fault plane. We develop a stochastic characterization of earthquake slip complexity, based on published finite-source rupture models, in which we model the distribution of slip as a spatial random field. The model most consistent with the data follows a von Karman autocorrelation function (ACF) for which the correlation lengths a increase with source dimension. For earthquakes with large fault aspect ratios, we observe substantial differences of the correlation length in the along-strike (ax) and downdip (az) directions. Increasing correlation length with increasing magnitude can be understood using concepts of dynamic rupture propagation. The power spectrum of the slip distribution can also be well described with a power law decay (i.e., a fractal distribution) in which the fractal dimension D remains scale invariant, with a median value D = 2.29 ± 0.23, while the corner wave number kc, which is inversely proportional to source size, decreases with earthquake magnitude, accounting for larger "slip patches" for large-magnitude events. Our stochastic slip model can be used to generate realizations of scenario earthquakes for near-source ground motion simulations.

Original languageEnglish (US)
JournalJournal of Geophysical Research: Solid Earth
Issue number11
StatePublished - Nov 10 2002


  • Complexity of earthquake slip
  • Correlation length of asperities growing with earthquake magnitude
  • Earthquake rupture dynamics
  • Earthquake source characterization
  • Spatial random fields
  • Strong ground motion simulation

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science


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