Japan Geoscience Union Meeting 2018

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[EE] Oral

S (Solid Earth Sciences) » S-IT Science of the Earth's Interior & Tectonophysics

[S-IT26] Stress geomechanics integrations: Observations, Modelings and Implications (OMI)

Sun. May 20, 2018 9:00 AM - 10:30 AM A01 (Tokyo Bay Makuhari Hall)

convener:HungYu Wu(Japan Agency for Marine-Earth Science and Technology), Weiren Lin(Graduate School of Engineering, Kyoto University), Yoshinori Sanada(（国研）海洋研究開発機構, 共同), Chung-Han Chan(Earth Observatory of Singapore, Nanyang Technological University), Chairperson:WU HungYU(Japan Agency for Marine-Earth Science and Technology), Chan Chung-Han(Earth Observatory of Singapore, Nanyang Technological University)

9:45 AM - 10:00 AM

[SIT26-04] Numerical simulations of the formation of a dynamic decollement

*Arthur Bauville1 (1.Department of Mathematical Science and Advanced Techology, JAMSTEC)

Keywords:accretionary prism, decollement

Decollements are often weak sedimentary layer that are deformed preferentially to form the base of an accretionary prism. However, in the Nankai Trough there is no clear evidence of a particular precursory layer. In this contribution, we discuss the mechanical conditions which can lead to the formation of a near horizontal thrust that acts as the basal shear zone of an accretionary prism. We performed numerical simulations of the deformation of a visco-elasto-plastic material with sandbox-type boundary conditions. We show that the imposed kinematic boundary condition lead to a stress state that allow for both the development of Andersonian fault that develop from the surface and non-andersonian, near horizontal fault that propagate from the indenter. Results from this simple numerical experiment are discussed in the light of available stress data from the Nankai accretionary prism.