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Insights into the Great Mw 7.9 Nepal Earthquake of 25 April 2015


Affiliations
1 Department of Applied Geophysics, Indian Institute of Technology (Indian School of Mines), Dhanbad 826 007, India
2 Life, Environmental and Earth Sciences Division, University of Bucharest, Romania
 

The 2015 Mw 7.9 earthquake occurred in the Nepal Himalaya between the Indian and Asian plates. The gravity modelling has been carried out along a 2D trench-orthogonal profile passing through the epicentre of this earthquake. The projections of mainshocks and aftershocks show their major confinement around the bending segment of the Indian upper crust (IUC). The operative shallowly plunging maximum compressive stress led to the accumulation of strain energy around the bending zone of the IUC, and triggered thrust-dominated southward movement of the Indian crustal block along a shallowly, dipping shear plane in the anisotropic layer. This can be broadly explained by three-stage rupture processes: the first one was associated with slow nucleation and rupture growth for early ~15 sec, the second one migrated upward, rupturing the uppermost part of the IUC for the next ~10 sec, and the third one propagated very fast during deformation for the remaining ~25 sec till the fracture- tip reached the overlying brittle Asian crust.

Keywords

2015 Nepal Earthquake, Frictional Sliding, Gravity Modelling, Indian Upper Crust.
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  • Insights into the Great Mw 7.9 Nepal Earthquake of 25 April 2015

Abstract Views: 321  |  PDF Views: 113

Authors

Prosanta Kumar Khan
Department of Applied Geophysics, Indian Institute of Technology (Indian School of Mines), Dhanbad 826 007, India
Md. Afroz Ansari
Life, Environmental and Earth Sciences Division, University of Bucharest, Romania
Dhananjay Singh
Department of Applied Geophysics, Indian Institute of Technology (Indian School of Mines), Dhanbad 826 007, India

Abstract


The 2015 Mw 7.9 earthquake occurred in the Nepal Himalaya between the Indian and Asian plates. The gravity modelling has been carried out along a 2D trench-orthogonal profile passing through the epicentre of this earthquake. The projections of mainshocks and aftershocks show their major confinement around the bending segment of the Indian upper crust (IUC). The operative shallowly plunging maximum compressive stress led to the accumulation of strain energy around the bending zone of the IUC, and triggered thrust-dominated southward movement of the Indian crustal block along a shallowly, dipping shear plane in the anisotropic layer. This can be broadly explained by three-stage rupture processes: the first one was associated with slow nucleation and rupture growth for early ~15 sec, the second one migrated upward, rupturing the uppermost part of the IUC for the next ~10 sec, and the third one propagated very fast during deformation for the remaining ~25 sec till the fracture- tip reached the overlying brittle Asian crust.

Keywords


2015 Nepal Earthquake, Frictional Sliding, Gravity Modelling, Indian Upper Crust.

References





DOI: https://doi.org/10.18520/cs%2Fv113%2Fi10%2F2014-2020