| 2-D viscoelastic FEM simulation on stress state in the deep part of a subducted slab |
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| 作者姓名： | 刘亚静 叶国扬 毛兴华 宁杰远 |
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| 作者单位： | LIU Ya-jing YE Guo-yang MAO Xing-hua NING Jie-yuan Department of Geophysics，Peking University，Beijing 100871，China |
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| 基金项目： | Pre-elected National Important Fundamental Research Project (95-S-05) and Foundation for University Key Teacher |
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| 摘 要： | Introduction It is found that there are some relationships between the thermal structures of subduction zones and the deep seismicity, while the mechanism relates the thermal structure and the deep seismicity is still unsure (Helffrich, Brodholt, 1991; Furukawa, 1994; Kirby, et al, 1996). From 1980s, geoscientists have constituted a series of numerical simulations on the stress states of subduction slabs. Based on the kinetic computation of Sung and Burns (1976a, b), Goto, et al (1983, 1987…
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| 收稿时间： | 15 January 2002 |
| 修稿时间： | 22 May 2002 |
2-D viscoelastic FEM simulation on stress state in the deep part of a subducted slab |
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| Liu Ya-jing , Ye Guo-yang , Mao Xing-hua and Ning Jie-yuan.2-D viscoelastic FEM simulation on stress state in the deep part of a subducted slab[J].Acta Seismologica Sinica(English Edition),2002,15(3):301-308. |
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| Authors: | Liu Ya-jing Ye Guo-yang Mao Xing-hua and Ning Jie-yuan |
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| Institution: | Department of Geophysics, Peking University, Beijing 100871, China |
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| Abstract: | The characteristics of the stress fields in deep subducting slabs are studied using viscoelastic plain strain finite element method. When introducing the new rheology structure given by Karato, et al into our computation, there emerge two regions with great shear stress just below the olivine-spinel phase transition zone, which encompass the low viscosity zone below the lower tip of the metastable wedge. Further, the directions of the main compressional stress of these two regions are all along the dip direction of the slab. These are in accordance with the seismic observations that there are two deep seismic zones in a slab and the directions of the main compressional stress in these two seismic zones are along the dip direction of the slab. Smaller effective viscosity probably caused by smaller grain size in the phase transformation zone does not have great influence on the stress state in the deep part of the slab. There is the maximum of shear stress at the transition region from olivine to spinel and the direction of the main compressional stress in this region is roughly perpendicular to the trend of the phase boundary no matter whether there exists metastable wedge, which nevertheless do not correspond to some well-known seismic observations. |
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| Keywords: | subduction zone stress state numerical simulation viscoelasticity deep seismicity |
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