DOI: 10.1007/s00531-014-1039-0
论文题名: Gravity anomalies, flexure, and deformation of the converging Indian lithosphere in Nepal and Sikkim-Darjeeling Himalayas
作者: Ansari M.A. ; Khan P.K. ; Tiwari V.M. ; Banerjee J.
刊名: International Journal of Earth Sciences
出版年: 2014
卷: 103, 期: 6 起始页码: 1681
结束页码: 1697
语种: 英语
英文关键词: Deformation
; Flexing
; Plate obliquity
; Seismicity
; Stress field
Scopus关键词: boundary condition
; compression
; convergent margin
; deformation mechanism
; earthquake mechanism
; finite element method
; flexure
; gravity anomaly
; lithospheric structure
; plate convergence
; plate tectonics
; seismicity
; stress field
; Darjeeling
; Himalayas
; India
; Nepal
; Sikkim Himalayas
; West Bengal
英文摘要: Abstract: Researchers ubiquitously noted that the common processes of partitioning oblique convergence in response to drag from the trench-hanging plate simultaneously produce radial slips, along-strike translation, and extension parallel to the deformation front. Here, we focus on the area between Nepal and Sikkim-Darjeeling Himalayas, and carry out gravity and finite-element stress modeling of the strike-orthogonal converging Indian lithosphere. We delineate the geometries of different layers and their interfaces through gravity modeling. The optimum model parameters along with rheological parameters of different layers are used for finite-element modeling. Finite-element modeling is done with boundary conditions of keeping the upper surface free and rigidly fixing the section of the northern boundary below the Main Himalayan Thrust. We impart on its frontal section an amount of 6 × 1012 N/m force, equivalent to resistive force of the Himalayan-Tibet system, and analyze the maximum and minimum compressive stress fields evolved in the lithosphere. We testify our observations with earthquake database and other geophysical and geological studies. We note that an increasing flexing of the Indian lithosphere beyond the Main Boundary Thrust becomes maxima between the Main Central Thrust and South Tibetan Detachment in both the areas; however, more steepening of the Moho boundary is identified in the Sikkim-Darjeeling Himalaya. This abrupt change in lithospheric geometry beneath the Greater Himalaya is likely correlated with the sharp elevation changes in the topography. Although the highest seismicity concentration is dominant in this zone, the Lesser and the Tethys Himalayas in Sikkim-Darjeeling area also record relatively fair seismic activity. More compressive stress field in different layers right within the sharp bending zone supports this observation. We thus propose that the sharp bending zone beneath the Greater Himalaya is suffering maximum deformation, and the deformation is continued in the mantle too. We also identify both right-lateral shear and radial vergence slip, which are presumably associated with the general dynamics and kinematics of the Himalaya. © 2014 Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906320221&doi=10.1007%2fs00531-014-1039-0&partnerID=40&md5=9226d35bcf0c7ab1f377ce5ae5172b53
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70389
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Department of Applied Geophysics, Indian School of Mines, Dhanbad, India; National Geophysical Research Institute, Hyderabad, India
Recommended Citation:
Ansari M.A.,Khan P.K.,Tiwari V.M.,et al. Gravity anomalies, flexure, and deformation of the converging Indian lithosphere in Nepal and Sikkim-Darjeeling Himalayas[J]. International Journal of Earth Sciences,2014-01-01,103(6)