Full-Text Search:
Home|Journal Papers|About CNKI|User Service|FAQ|Contact Us|中文
《Chinese Journal of Geophysics》 2004-02
Add to Favorite Get Latest Update

GENETIC ALGORITHM-FINITE ELEMENT INVERSION OF DRAG FORCES EXERTED BY THE LOWER CRUST ON THE UPPER CRUST IN THE SICHUAN-YUNNAN AREA

ZHU Shou-Biao 1,2 SHI Yao-Lin 2 1 Department of Geophysics, Peking University, Beijing 100871, China 2 National Key Lab of Calculation Geodynamics, Chinese Academy of Sciences, Beijing 100039, China  
Based on data of focal mechanism and geological survey, the boundary forces and shear forces on the bottom of the upper crust are inversed with the pseudo-3D genetic algorithm finite element method (GA-FEM) for the Sichuan-Yunnan area (96°E~104°E, 22°N~30°N) in southwest China. The inversion method is discussed, and stable result is obtained. The result shows that the direction of shear forces on the bottom of the upper crust in the Sichuan-Yunnan rhombus-shape block applied by the lower crust is south-southeast, which is consistent with the orientation of present crust movement revealed by GPS measurements in general, but significant shear forces are not found beneath the upper crust in other parts of the study area. Combined with other research results, we conclude that the lower crust drags the upper crust in the Sichuan-Yunnan rhombus-shape block since the lower crust is easy to flow than the upper crust in the process of mass movement toward east and southeast when the Tibetan Plateau is pushed. The model displacements inversed from the stress field agree with present displacements measured by GPS. It indicates that the inversion result is reaso- nable and has physical significance.
【Fund】: 国家自然科学基金项目 ( 4 99740 2 3 )
【CateGory Index】: P542
Download(CAJ format) Download(PDF format)
CAJViewer7.0 supports all the CNKI file formats; AdobeReader only supports the PDF format.
©2006 Tsinghua Tongfang Knowledge Network Technology Co., Ltd.(Beijing)(TTKN) All rights reserved