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No.83 (2007/3) >

 
Title :FEM simulation of fold-and-thrust belts in the South Central High Andes of Chile and Argentina
Authors :Islam, Md. Rafiqul
Hayashi, Daigoro
Authors alternative :林, 大五郎
Issue Date :Mar-2007
Abstract :FEM analysis for stress determination of fold-and-thrust belts of the South Central High Andes (SCRA) was carried out on Paleozoic to Quaternary rocks from the Coastal Cordillera to Precordillera regions of the Chile and Argentinean Andes, between 30^o and 33^o south latitudes. A two-dimensional vertical cross-section including 8 layers through the Andean crust up to Moho has been represented by a finite element model composed of an assembly of 2699 elements and 1456 nodes in a state of plane strain conditions. The model is assumed to be multilayered lithospheric crustal block undergoing convergence. and we choose to demonstrate our results by applying horizontal displacement rate (average velocity of 6.50 cm/yr) of descending Nazca plate. The failure of elements is defined by adopting the concept of Mohr-Coulomb failure criterion. The assigned rock rheology and physical properties of each layer in simulation make the model behavior as elastic body in which well defined failure location gives a hint of thrust development. Studies of lithospheric deformation of the fold-and-thrust belts in this zone where structural style varies from thinskinned to thick-skinned fold-and-thrust belts have revealed various compressional states of stress. The maximum compressional stress (σ_1) was generally oriented in an E-W direction. Along the westernmost part of the Coastal Cordillera, the strain deformation is extensional in some elements. which can be explained by a co-seismic crustal bending readjustment. Overall study results imply that most of the basement-involved deep thrusts (about 20 km) and deformation. occurred within the upper crustal parts that lie in. Layers-4, 5 and 6, are more likely related to crustal anisotropy.
Type Local :紀要論文
ISSN :0286-9640
Publisher :琉球大学理学部
URI :http://hdl.handle.net/20.500.12000/447
Citation :琉球大学理学部紀要 = Bulletin of the College of Science. University of the Ryukyus no.83 p.29 -60
Appears in Collections:No.83 (2007/3)

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