Curvature interpretation of gravity data for delineating structural features across the transition zone of Narmada–Son lineament in central India

Abstract

Potential-field anomalies can be converted to a common function which describes the ridge, peaks over an isolated source. In this study, attempt has been made to interpret curvature attributes of equipotential surface using gravity gradients for delineating thrust–fault locations in one of the seismically active transition zones of Narmada–Son Lineament (NSL) in central India. The NSL is oriented in the ENE–WSW direction, divides the area into two geological provinces. The northern part of this NSL comprises Vindhyan formations and southern part covers Gondwana formations. It has been observed that, the northern part (around Jukehi) of the area has higher elevation with lower gravity anomaly and the southern part (around Khamaria and Kataria) has lower elevation with higher gravity anomaly. The tectonic activities like intrusions, volcanisms and earthquake occurrences were the sources of crustal resettlement during the past in this area. Various researchers commented about the structural configuration; however, the present study helps to understand the structural features using various curvature analysis like maximum, minimum, most-positive, most-negative, mean, dip (profile), strike (tangential), contour (plan), curvedness, shape index and Gaussian curvatures. Out of these curvatures most positive, maximum, mean, dip and curvedness show more effective results compared to other curvatures. However, shape index states domes, ridge, flat, valley, bowl shape type structures. The results are also correlated with the conventional horizontal gravity gradient, analytic signal and tilt derivative analysis. The colour contrast variation of these differential curvatures make in-depth understanding with extensive multiplicities of integrity for delineating subsurface structures.