Geomorphic signatures and active tectonics in western Saurashtra, Gujarat, India

Active tectonics in an area includes ongoing or recent geologic events. This paper investigates the tectonic influence on the subsidence, uplift and tilt of western Saurashtra through morphotectonic analysis of ten watersheds along with characteristics of relief and drainage orientation. Watersheds 7–9 to the north (N) are tectonically active, which can be linked with the North Kathiawar Fault System (NKFS) and followed by watersheds 6, 10, 1, 4 and 5. Stream-length gradient index and sinuosity index indicate the effect of tectonic events along the master streams in watersheds 6–9. Higher R2values of the linear curve fit for watershed 7 indicate its master stream is much more tectonically active than the others. The R2curve fitting model and earthquake magnitude/depth analysis confirm the region to be active. The reactivation of the NKFS most likely led to the vertical movement of western Saurashtra.