Active faulting in apparently stable peninsular India: Rift inversion and a Holocene-age great earthquake on the Tapti Fault

Copley, Alex and Mitra, Supriyo and Sloan, R. Alastair and Gaonkar, Sharad and Reynolds, Kirsty (2014) Active faulting in apparently stable peninsular India: Rift inversion and a Holocene-age great earthquake on the Tapti Fault. Journal of Geophysical Research: Solid Earth, 119 (8). pp. 6650-6666. DOI https://doi.org/10.1002/2014JB011294

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Abstract

We present observations of active faulting within peninsular India, far from the surrounding plate boundaries. Offset alluvial fan surfaces indicate one or more magnitude 7.6–8.4 thrust-faulting earthquakes on the Tapti Fault (Maharashtra, western India) during the Holocene. The high ratio of fault displacement to length on the alluvial fan offsets implies high stress-drop faulting, as has been observed elsewhere in the peninsula. The along-strike extent of the fan offsets is similar to the thickness of the seismogenic layer, suggesting a roughly equidimensional fault rupture. The subsiding footwall of the fault is likely to have been responsible for altering the continental-scale drainage pattern in central India and creating the large west flowing catchment of the Tapti river. A preexisting sedimentary basin in the uplifting hanging wall implies that the Tapti Fault was active as a normal fault during the Mesozoic and has been reactivated as a thrust, highlighting the role of preexisting structures in determining the rheology and deformation of the lithosphere. The slip sense of faults and earthquakes in India suggests that deformation south of the Ganges foreland basin is driven by the compressive force transmitted between India and the Tibetan Plateau. The along-strike continuation of faulting to the east of the Holocene ruptures we have studied represents a significant seismic hazard in central India.

Item Type:	Article
Additional Information:	The paper was selected as the Editors' Highlight for August 2014 http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%292169-9356/homepage/EditorsHighlights.html
Uncontrolled Keywords:	2014AREP; IA68;
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access 12 - PhD
Journal or Publication Title:	Journal of Geophysical Research: Solid Earth
Volume:	119
Page Range:	pp. 6650-6666
Identification Number:	https://doi.org/10.1002/2014JB011294
Depositing User:	Sarah Humbert
Date Deposited:	19 Sep 2014 15:36
Last Modified:	09 Jan 2019 13:34
URI:	http://eprints.esc.cam.ac.uk/id/eprint/3121

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