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No.87 (2009/3) >

 
Title :FE simulation of stress field and crustal deformation around Southern Ryukyu Arc
Authors :Suzuki, Ryota
Hayashi, Daigoro
Authors alternative :林, 大五郎
Issue Date :Mar-2009
Abstract :Finite element (FE) modeling has designed to investigate dynamics of Southern Ryukyu Arc based on synthesized stress-strain, velocity, geology and seismicity data. Result of horizontal minimum stress (σHmin) orientation is compared to present stress distribution. We constructed 1300 km X 600 km model for Southern Ryukyu Arc. FE model was bounded along the Ryukyu Trench. Studied region is divided into 3 domains: arc region, Okinawa Trough and continental margin. As displacement velocity is 9.0 cm/yr in Taiwan, we set up NW boundary displacement of 2000 m that correspond to c.a. 20,000 year on Ryukyu Trench to Taiwan. Four boundary conditions under 1, 10 and 30 km depth are considered. In addition, single domain model is also constructed. Total 16 experiments are performed. Result of σHmin orientation shows good agreement with T-axis distribution in Taiwan and Ryukyu Arc (Kubo and Fukuyama, 2003; Otsubo and Hayashi, 2003). In addition, large stress concentrates on eastern area of Taiwan while in Okinawa trough, computed σHmin orientation is arc-parallel which is inconsistent with observed σHmin orientation. Depth affects greatly to the stress magnitude but not to stress orientations in the Ryukyu Arc. It is found that orientation of σHmin is principally controlled by rock domain properties of major structural zones and the direction of convergence of the Philippine Sea plate relative to Eurasia. Direction of displacement vector is good agreement with that of observed velocity field in Taiwan, while direction of displacement vector is trending NW or W in Okinawa trough and Ryukyu Arc, indicating that this model does not fit in this point.
Type Local :紀要論文
ISSN :0286-9640
Publisher :琉球大学理学部
URI :http://hdl.handle.net/20.500.12000/9530
Citation :琉球大学理学部紀要 = Bulletin of the College of Science. University of the Ryukyus no.87 p.47 -68
Appears in Collections:No.87 (2009/3)

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