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Published January 28, 2016 | Supplemental Material + Published
Journal Article Open

Terrane‐controlled crustal shear wave splitting in Taiwan


Taiwan is the result of arc‐continent collision associated with the convergence of the Philippine Sea plate with the eastern Eurasian plate continental margin. The locus of deformation is found in eastern Taiwan in the form of mountain building (Central Range) with underlying thickened lithosphere. Rapid tectonic exhumation in the Central Range has uncovered low‐to‐high‐grade metamorphic rocks marked by steep cleavage. We carried out a crustal seismic anisotropy study across Taiwan, producing a database of over 27,000 local earthquake shear wave splitting measurements. Additionally, we carried out rock physics measurements of metamorphic outcrop samples to quantify shear wave rock anisotropy. We produced a map of station‐averaged splitting measurements across Taiwan. Patterns of fast shear wave directions correlate with tectonic terranes produced by plate convergence. Deformation‐related mineral‐preferred orientation in the metamorphic rocks produces a significant amount of the crustal anisotropy in the Taiwan collision zone.

Additional Information

© 2015. American Geophysical Union. Received 6 OCT 2015. Accepted 17 DEC 2015. Accepted article online 19 DEC 2015. Published online 16 JAN 2016. This study was funded by the NSF Continental Dynamics program under awards NSF EAR‐1009691 (D.O.), EAR‐0410227 (N.C.), and EAR‐1010645 (F.W.). We thank Martha Savage and an anonymous reviewer for their helpful comments. We also thank Wen‐Tzong Liang, C.‐Y. Wang, and B.‐S. Huang for providing additional seismological data and Yuan‐Hsi Lee who guided our field excursion to collect Central Range rock samples. Seismological waveform data used in this study are available from the Taiwan TEC Data Center (http://www.tecdc.earth.sinica.edu.tw) and from IRIS DMC (http://www.iris.edu). The authors created the figures using GMT [Wessel and Smith, 1998].

Attached Files

Published - Okaya_et_al-2016-Geophysical_Research_Letters.pdf

Supplemental Material - downloadSupplement_doi=10.1002_2F2015GL066446_file=grl53874-sup-0001-supplementary.pdf

Supplemental Material - downloadSupplement_doi=10.1002_2F2015GL066446_file=grl53874-sup-0002-supplementary.pdf


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