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Indo-Gangetic plain; Himalaya; resistivity; magnetotelluric; 1D inversion; dimensionality.

Knowledge of the sedimentary thickness and configuration of the basement structure are important to estimate the seismic hazards in active foreland basin. We present sedimentary thickness of the northern Indo-Gangetic plain estimated from impedance tensors of 12 magnetotelluric sites. Occam’s one dimensional inversion scheme was applied to invariant of the magnetotelluric tensors for the period range of 0.001–1 sec at each site. Inverted one dimensional model corroborates north-easterly dipping Indian basement and accordingly increased thickness of the sedimentary column towards north and east direction. The top sedimentary layers of varying thickness and resistivity are correlated with the known borewell logs and previous geophysical studies around the study area. Significant difference is observed in the resistivity of the Indian basement and thickness of the sedimentary column across the Delhi Hardwar Ridge. The difference in resistivity may be an indicative of variation in compactness and degree of saturation of the sedimentary cover and the nature of the Indian basement rock across the Delhi Haridwar Ridge.

DHAMODHARAN S^{1 2} GAUTAM RAWAT¹ SACHIN KUMAR¹ BAGRI D S²

1. Wadia Institute of Himalayan Geology, 33 GMS Road, Dehradun, India.
2. Hemwati Nandan Bahuguna Garhwal University, Srinagar, India.

Published

20 July 2020

Manuscript received

27 August 2019

Manuscript revised

2 April 2020

Accepted

17 April 2020

Final version published online

15 July 2020