2-D elastic FEM simulation on stress state in the deep part of a subducted slab

• Published in: Acta seismologica sinica Vol. 15; no. 3; pp. 294 - 300
• Main Author: MAO Xing-hua (毛兴华) LIU Ya-jing (刘亚静) YE Guo-yang (叶国扬) NING Jie-yuan (宁杰远)
• Format: Journal Article
• Language: English
• Published: Beijing Springer Nature B.V 01.05.2002; Department of Geophysics, Peking University, Beijing 100871, China
• Subjects: Computer simulation; deep; Density; Earthquakes; elasticity; Finite element method; Mathematical models; Mineralogy; numerical; Olivine; Seismic activity; Seismicity; simulation; state; stress; Stress concentration; Stress state; Stresses; subduction; Thermal stress; Transition zone; zone; stress state; deep seismicity; elasticity; numerical simulation; subduction zone
• ISSN: 1000-9116; 1674-4519; 1993-1344; 1867-8777
• DOI: 10.1007/s11589-002-0062-6

Based upon some simplified numerical models, a 2-D plain strain elastic FEM program is compiled to study the distributions of the stress fields produced by the volume change of the phase transformation from olivine to spinel, by the volume change from temperature variation, and by density difference and boundary action in a piece of subducted slab located in transition zone of the mantle. Thermal stress could explain the fault plane solutions of deep focus earthquakes, but could not explain the distribution of deep seismicity. When large extent metastable olivine is included, the stress field produced by the density difference contradicts with the results of fault plane solutions and with the distribution of deep seismicity. Although the stress produced by volume change of the phase transformation from olivine to spinel dominates the stress state, its main direction is different from the observed results. We conclude that the deep seismicity could not be simply explained by elastic simulation.