Inversion of GPS velocity and seismicity data to yield changes in stress in the Japanese Islands

Takeshi Iinuma, Teruyuki Kato, Muneo Hori

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

To estimate stress changes within the crust from observed displacement rates, we have devised a new stress inversion method for a 2-D plate subjected to a planar stress which uses Airy's stress function. The merits of this stress inversion method are that it allows us to estimate the stress field without full knowledge of the elastic properties of the object and it improves precision because it is not necessary to take derivatives of observed quantities. We applied this stress inversion method to the Japanese Islands where the Geographical Survey Institute has been operating a nationwide GPS array called 'GEONET'. We make the assumption that the inelastic deformation in the Japanese Islands has no dilatational component. We used velocity data derived from 3 yr of GPS observations. We estimated the change in boundary traction from the seismic parameters of large earthquakes (stress drop, slip direction and recurrence interval). We compared the observed 'total' strain and estimated the 'elastic' strain. The results suggest that the latter looks larger than the former, indicating that it is feasible to estimate the distribution of rigidity from the stress inversion. Comparison with seismicity data suggests that inland shallow earthquakes occur where rigidity is lower.

Original languageEnglish
Pages (from-to)417-434
Number of pages18
JournalGeophysical Journal International
Volume160
Issue number2
DOIs
Publication statusPublished - 2005 Feb

Keywords

  • Airy's stress function
  • GPS network
  • Inverse analysis
  • Japan

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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