Joint Vp and Vs tomography of Taiwan: Implications for subduction-collision orogeny

Hsin Hua Huang, Yih Min Wu, Xiaodong Song, Chien Hsin Chang, Shiann Jong Lee, Tao Ming Chang, Hung Hao Hsieh

Research output: Contribution to journalArticlepeer-review

Abstract

The Taiwan orogen sitting at the pre-rifted Eurasian margin and bracketed by two sub-orthogonal subduction systems is subject to complicated geotectonics, motivating numerous seismic tomographic studies in local and regional scale. Most of them obtained P-wave velocities (Vp), or with Vp/Vs ratio jointly, but few were for S-wave velocities (Vs). With unprecedented amount of S-wave data, in this study a new set of well-tuned Vp, Vs, and Vp/Vs models were determined by an elaborate joint-inversion scheme, integrating the data of P- and S-wave travel times, S-P times, and the borehole logging data (for near-surface correction) into one system. This allowed us to revisit the subduction-collision process in detail by comparing Vp, Vs, and Vp/Vs ratio simultaneously. With enhanced slab imaging of Philippine Sea Plate (PSP) under northeast Taiwan, we are able to discriminate the plausible missing Luzon forearc basement along the plate boundary and propose a "skateboarding" edge model, in which the westernmost PSP rides on the east-subducted forearc basement and subducts northward underneath the Eurasian lithosphere. The underlain forearc basement along with the PSP subduction then results in the anomalous shallow double seismic zone observed only near Taiwan Island. Meanwhile, at around 121°E the north-subducting PSP seems dipping west to collide with the deep Eurasian lithosphere, shaping an irregular corner wedge structure. In addition, we evaluate our model with previous ones by waveform modeling approach and show the current performance of travel-time tomography in Taiwan region.

Original languageEnglish (US)
Pages (from-to)177-191
Number of pages15
JournalEarth and Planetary Science Letters
Volume392
DOIs
StatePublished - Apr 15 2014

Keywords

  • Borehole logging data
  • Joint inversion
  • Model evaluation
  • Plate boundary
  • Taiwan orogeny
  • Travel-time tomography

ASJC Scopus subject areas

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

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