Morphometric indices assessment: Implications for active tectonics in the upper Narmada Basin, central India

During the Palaeoproterozoic era, the Northern and Southern cratonic blocks of the Indian Plate came together and amalgamated. Farther, facilitated by the East-West trending central Tectonic Suture Zone, characterized by the Son-Narmada Fault/Lineament (SNF/L) and Central Shear (CIS) Zone, has long intrigued researchers due to its implications for active tectonics, particularly in the Narmada basin. In this study, we employ geomorphic and morphotectonic indices to elucidate the neotectonic activity in the Upper Narmada basin (UNB) of central India. Utilizing SRTM-DEM data, we analyze morphometric and morphotectonic parameters to shed light on the development of drainage patterns and active tectonics within the basin. Our findings reveal a pronounced influence of tectonics on basin evolution, as evidenced by high bifurcation ratios indicative of intense tectonic activity and elevated ruggedness values suggestive of heightened erosion susceptibility. The predominant ENE-WSW orientation of the Son Narmada South Fault (SNSF) and Son Narmada North Fault (SNNF), aligned with major lineament trends, exerts control over the Narmada River drainage network. Additionally, the high value (<50) of the asymmetric factor reveals the significant tectonic influence on the Upper Narmada basin, while the transverse asymmetric factor and stream length index values further corroborate the basin's susceptibility to active tectonics. Notably, the abrupt elevation changes (200–600 m asl) reflected by Dhuandhar, Kapildhara and other falls along the course of Narmada provide compelling evidence of neotectonic activity. Thus, we assert that morphotectonic analyses employing Digital Elevation Maps, satellite imagery, and SRTM-DEM data represent an efficacious approach for investigating complex basin morphotectonics.