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Title :Numerical Modelling of Graben Faults with Special Reference to Thakkhola Half Graben, Central Nepal Himalaya
Authors :Chamlagain, Deepak
Hayashi, Daigoro
Authors alternative :林, 大五郎
Issue Date :2006
Abstract :Thakkhola half graben is a product of Late Cenozoic extensional tectonics in the Himalaya-Tibetan region. A series of 2D finite element models are generated to simulate its first order characteristics using stress field and induced fault pattern as structural proxies. Extensional graben faults form in the upper weak layer and propagate downward with increasing extension. Clusters of failure elements at the two ends of the graben directly correspond to the graben bounding faults and the asymmetric feature is characterized by uneven development of faults therein. The syntectonic deposits are characterized by normal fauls in the tensional stress field, which is a common feature of the small-scale graben at post rift deformation stage. The proposed models suggest that depth of a graben growth fault is primarily controlled by the initial fault and density of the syntectonic deposits. Assumption of a weak zone (Thakkhola fault system) does not make significant difference in stress distribution and faulting. It is thus suggested that a weak zone only can not contribute to the development of a half graben. The spreading boundary condition could not simulate the existing fault configuration in the Thakkhola half graben. Our modelling results for the graben suggest gravitational collapse of the elevated plateau rather than mantle upwelling during spreading.
Type Local :雑誌掲載論文
Publisher :Wadia Institute of Himalayan Geology
URI :http://hdl.handle.net/20.500.12000/3011
Citation :Himalayan Geology Vol.27 no.2 p.95 -110
Appears in Collections:Peer-reviewed Journal Articles (Faculty of Science)

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