[S-SS07] [EE] 地表地震断層の調査・分析・災害評価

[SSS07-P02] Shallow crustal structures triggered by the M_L6.6 Meinong earthquake, southwestern Taiwan, from field investigation of surface deformation and damages

*Ling-Ho Chung¹、Ray Y Chuang²、J Bruce H Shyu³、Mong-Han Huang⁴、Kenn-Ming Yang⁵、Kuo-En Ching⁶、Yuan-Hsi Lee¹ (1.Department of Earth and Environmental Sciences, National Chung Cheng University、2.Department of Geography, National Taiwan University、3.Department of Geosciences, National Taiwan University, Taipei, Taiwan、4.Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA、5.Department of Earth Sciences, National Cheng Kung University、6.Department of Geomatics, National Cheng Kung University)

キーワード：Meinong earthquake, InSAR

The M_L6.6 Meinong earthquake on 6 February 2016 caused serious damages in southwestern Taiwan. Coseismic displacement derived from GPS and InSAR shows ~10 cm dome-shaped surface uplift 15 km west of the epicenter with two clear N-S trending discontinuities in the InSAR fringes around the town of Guanmiao, which are highly related to building damages and surface cracks observed in the field. In this study, we integrate seismic reflection data, geologic data, and results from field investigation to construct shallow crustal structural geometry. The two lineaments near Guanmiao seen in the InSAR result may be induced by local shallow folding in the Liushuang - Erhchuangchi (LS-EC) Formation. Instead of being a traditional fault-bend fold, the significant uplift west of Guanmiao may be associated with pure shear deformation of clayey Gutingkeng (GTK) Formation. Our result suggests that lower crustal earthquakes can trigger active structures at shallower depths, which is capable of generating localized surface deformation and damages.