Using finite element and Okada models to invert coseismic slip of the 2008 Mw 7.2 Yutian earthquake, China, from InSAR data

Chisheng Wang, Xinjian Shan, Changlin Wang, Xiaoli Ding, Guohong Zhang, Timothy Masterlark

Research output: Journal article publicationJournal articleAcademic researchpeer-review

9 Citations (Scopus)

Abstract

We invert InSAR from ascending and descending passes of ENVISAT/ASAR data to estimate the distribution of coseismic slip for the 2008 Mw 7. 2 Yutian earthquake by separately using uniform finite element models (FEMs), non-uniform FEMs, and analytical elastic half-space (Okada) models. We use the Steepest Descent method and Laplacian smoothing to regularize and estimate the slip distribution for each of these different models. Fault surface ruptures interpolated from Quickbird optical images constrain the strike of the fault. The uniform FEM and Okada models assume a fault embedded in a homogeneous and elastic finite domain or half-space, respectively, while the non-uniform FEM describes a domain with spatially variable elastic properties according to the geological structure of Tibet plateau and Tarim. We find that the estimated slip distribution of the non-uniform FEM is similar to that of the uniform FEM but has a slightly larger moment (~2 %). However, more noticeable discrepancies occur between the slip distributions of the uniform FEM and Okada model, where the slip pattern estimated with the FEM looks more scattered and locates at a lower depth. We conclude that, for the case of the Yutian earthquake, the improvement brought by simulating the distribution of geologic material properties is insignificant. This suggests that the uniform geologic structure of Okada models may be sufficient for simulating large intra-continental earthquakes.
Original languageEnglish
Pages (from-to)347-360
Number of pages14
JournalJournal of Seismology
Volume17
Issue number2
DOIs
Publication statusPublished - 9 Apr 2013

Keywords

  • Coseismic slip
  • Finite element model
  • InSAR
  • Okada model
  • Yutian earthquake

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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