Observation of surface displacements from GPS analyses before and after the Jiashian earthquake (M=6.4) in Taiwan

Chieh Hung Chen, Strong Wen, Ta Kang Yeh, Chung Ho Wang, Horng Yuan Yen, Jann Yenq Liu, Yasuhide Hobara, Peng Han

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

A blind thrust fault with a unique strike, which is orthogonal to the strike of most tectonic structures in Taiwan, triggered the Jiashian earthquake on March 4, 2010 (M=6.4; 22.96°N, 120.70°E). This study utilizes 100 global positioning system stations to examine changes of surface displacements during the Jiashian earthquake. We mitigate effects of short-term noise and long-term plate movements from surface displacement data using a frequency dependent filter via the Hilbert-Huang transform and compute the horizontal azimuth (i.e. GPS-azimuth) using residual data at the NS component relative to residual data at the EW component. Analytical results show that orientations of horizontal azimuths were aligned and orthogonal to the strike of the blind thrust fault. Meanwhile, inverse orientations are observed before and after the earthquake that agrees well with the seismic rebound theory. As stress disturbed on strata a few days before the earthquake, an impeded region can be clearly identified by disordered orientations of horizontal azimuths for anticipating the mainshock. These results provide an additional view to explore stress disturbance associated with earthquakes and offer more information to examine diverse models of tectonic evolution in this region.

Original languageEnglish
Pages (from-to)662-671
Number of pages10
JournalJournal of Asian Earth Sciences
Volume62
DOIs
StatePublished - 30 Jan 2013

Keywords

  • Global positioning system
  • Hilbert-Huang transform
  • Jiashian earthquake

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