Reassessment of high strain rate and seismic hazar

报告题目：Reassessment of high strain rate and seismic hazards in SW Taiwan: Insight from 2016 Mw 6.4 Meinong Earthquake and numerical modeling

学术报告人：胡植庆教授，台湾大学

主持人：陈强教授、刘国祥教授

时间：2017年5月12日（周五），上午10:00

地点：犀浦校区X4431会议室

主讲人简介：胡植慶，台灣大學地質科學系專任教授，法國巴黎第六大學博士，專長領域：地體動力學；數值模擬；大地測量；衛星遙測影像。

讲座内容简介：Anomalous high strain accommodation across the fold-and-thrust belt in SW Taiwan are revealed by the Continuous GPS, precise leveling and SAR interferometry. It is surprising to notice that the footwall of Longchuan reverse fault demonstrates a high uplift rate of ~20-30 mm/yr in interseismic period. This anomalous deformation rate might part be related with a ramp duplex located in the footwall of the Longchuan reverse fault and the triggered slip of moderate earthquake in nearby area. A clear evidence of multiple fault slip along a fold-and-thrust belt at 5-10 km depth was triggered by the 2016 Mw 6.4 Meinong earthquake at 15-20 km depth. We hypothesize that the surface coseismic deformation is mainly controlled by a structure related to the shallow detachment at around 5-10 km depth, which a proposed duplex in a region of high pressure and high interseismic uplift rate might be sensitive to stress perturbations induced by moderate lower crustal earthquake. In addition, the mechanical heterogeneity of mudstone in the Gutingkang formation might play a crucial role of anomalous deformation. Consequently, we use an Efficient Unstructured Finite Element method (DynearthSol2D) to simulate and discuss the contrast of viscosity in mudstone and sandstone contributed in deformation pattern and upward mobility. We also want to check the previous hypothesis of mud diapirism and incorporate a new mud-cored anticline model for mechanic explanation of anomalous interseismic deformation occurred in SW Taiwan. The numerical predicts an uplift rate of ~10 mm/yr of active folding related to ramp duplex in the footwall of the Longchuan reverse fault. The uplift rate could reach to ~20 mm/yr with incorporating the high pressure zone in the ramp duplex and a backthrust of the in the footwall of the Longchuan reverse fault, which is in good agreement with the uplift rate from precise leveling. Thus we conclude that the high mobility of mud-core anticline responsible for anomalous high deformation in SW Taiwan.

主办：研究生院

承办：地球科学与环境工程学院

胡植庆教授，台湾大学

犀浦校区X4431会议室