文章基本信息

标题：Tectonic Implication of the 5th March 2005, Doublet Earthquake in Ilan, Taiwan
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作者：En-Chao Yeh ; Yih-Min Wu ; J. Bruce H. Shyu 等
期刊名称：Terrestrial Atmospheric and Oceanic Sciences
印刷版ISSN：1017-0839
出版年度：2016
卷号：27
期号：6
页码：799-805
DOI：10.3319/TAO.2016.02.26.01(T)
出版社：Chinese Geoscience Union
摘要：The 5 th March 2005 earthquake doublet focal mechanism was determined as strike-slip faulting from Harvard and BATS moment tensor inversion. However, based on first motion polarities, the first shock has a normal focal mechanism (Wu et al. 2008a). This discrepancy has caused a debate over the focal mechanism solution because different focal mechanisms have different tectonic implications. Based on the dislocation determination from Global Position System (GPS) measurements, we find this event includes both tensile and strike-slip components. This finding illustrates the reason for the differences in the determined focal mechanisms using two different types of seismic data and analyzing methods. Field mapping and microstructure examination results indicate that the ductile deformation around the study area was characterized by the evolution from transpression to transtension with a predominant strike-slip component, but present-day active structures may be dominated by normal faulting. Thus, the active tensile slip result determined from dislocation modeling strongly suggests that the back arc extension of the Okinawa trough influences the stress state in this region, and changes the major transtension from strike-slip faulting to normal faulting.
关键词：Ilan Plain; Okinawa Trough; Focal mechanism; CLVD; GPS; Ductile deformation;