Original paper

Delineating the spatial variability in neotectonic activity along the southwestern Saurashtra, Western India

Gandhi, Drasti; Prajapati, Parnavi; Prizomwala, S. P.; Bhatt, Nilesh; Rastogi, B. K.

Abstract

The morphometric analysis using geostatistical information of various landforms has proved useful in delineating areas of active deformation. Here we present the study of five drainage basins, namely Saraswati, Heran, Devka, Megal and Noli flowing into the Arabian Sea on Kathiawar peninsula, now called Saurashtra using quantitative geomorphologic approach to delineate the spatial variability in neotectonic activity. The geomorphic indices of active tectonics namely longitudinal river profile, stream length-gradient index, valley floor width-height ratio, asymmetry factor, transverse topography asymmetry, elongation ratio and pseudo-hypsometric integral were used to identify the areas undergoing active deformation and tilting. On the basis of drainage anomalies and quantitative geomorphic parameters, three faults were delineated namely, 1) Girnar fault (NE-SW oriented), 2) F1 (E-W oriented) and 3) F2 (WNW-ESE oriented). The quantitative approach also enabled us to divide the study area into three segments on basis of extent of neotectonic activity: Segment I: least active and tilting towards WNW direction, Segment II: active with variable tilt and epicenter of major seismic events and Segment III: most active with variable tilt but lower seismicity.

Keywords

neotectonicssl indexsaurashtrageomorphic indicesdrainage anomaly