Geomorphic response of the river basin drainage in seismically active regions of India

Over the last few decades, the Indian subcontinent is gradually drifting towards northeast at a rate of 10 mm/year, which is an indication that the areas are actively deforming. Such a gradual rate of drift is expected to bring modifications and changes in the topography, which can be quantified with the help of geomorphic parameters. The current study examines the geomorphological changes in the seismically active areas of different geotectonic provinces of India, i.e., Northeast India and Bhuj region. The geomorphological changes have been estimated with the help of remote sensing and geographical information system modeling by calculating the geomorphic parameters. A total of 39 drainage basins were extracted from both the study areas using Aster GDEM data of 30 m resolution. Geomorphic indices such as stream order, stream length, bifurcation ratio, form factor, asymmetry factor and hypsometric integral were calculated for each drainage basin of the study regions. The geomorphic parameters reveal that the study areas are dendritic in character, even though having different geological formations, both study regions express similar lithological characteristics. With no strong control of structural elements, both study areas seem to be characterized by relatively high permeability and with relatively gentle slope. The extent of the carving of topography reveals that the drainage development and morphologic evolution of both areas have practically reached Late Mature and Old stage of terrain development. Even though the two study areas represent different seismotectonic provinces, it is observed that geomorphologically they are gradually approaching the stage of peneplanation.