Finite Element Modeling of Extensional Structures in the Annapurna Region of Central Himalayas

Abstract

Two-dimensional, elastic, plane-strain, finite element model are generated to investigate the extensional structures mainly normal fault in the Annapurna region, central Himalaya. The numerical study was performed on the Miocene geologic profile considering both of the convergent displacement and rock layer properties in the regime. Results show that the normal fault primarily influenced by model geometry, rheology (layer properties) and boundary condition (applied convergence displacement). Simulated normal fault density exhibits very high intensity in Lesser Himalaya then in the Tethys Himalaya and low intensity in the Higher Himalaya, suggesting the vulnerability of fault development to low-grade metamorphic rock than the high-grade rocks. The location of normal fault predicted by the numerical model analysis is consistent to the position of normal fault segments by Kaneko (J Geol Soc Jpn 103(3):203–226, 1997). In this studies, it also believed that the presence of these normal faults and underthrusting of the sub-Himalayan sequence with associated tectonic forces, the Himalayan Metamorphic belt has been exhumed and differentially domal uplifted and then segmented into several blocks.