Resistivity survey across the Narmada-Son lineament and along the Sanwer-Borgaon traverse, Madhya Pradesh, central India

Combined Schlumberger and equatorial Direct Current (DC) dipole soundings were conducted along the Sanwer-Borgaon traverse across the Narmada-Son lineament primarily to locate the shallow-level faults and fractures after two intraplate earthquakes that rocked Jabalpur and Khandwa in Madhya Pradesh, central India. The study area is covered by Deccan basalts overlying the Gondwana, Vindhyan and Bijawar sediments and the basement is of Bundelkhand granite. A 2D model from a 1D inversion of sounding data revealed that the thickness of the Deccan trap varies from 600 m to 1 km along the Sanwer-Borgaon traverse. Occurrence of abundant water within the subsurface formations in the Dulhar zone, and further south, one conductive thick zone, presumably due to highly weathered Deccan trap or intratrappeans, have been inferred. A sudden increase in depth of the basement north of the Narmada-Son lineament indicates that a major fault coincides with the Narmada River. Collinear dipole-dipole traverses were taken across the surface geological signature of faults. The survey was able to locate a couple of faults/fractures along the traverse within 2 km of the Earth�s crust. The area appears to be a tectonically weak zone. Both resistivity sounding and profiling techniques proved to be very useful tools for understanding the lithology and structure below the Deccan trap.