Tectono-Geomorphic assessment in the Barak River Basin of Western Hills of Manipur, using Remote Sensing and GIS techniques.

Manipur Hills of Indo Myanmar range (IMR) is tectonically very active as indicated by the recent 6.7 Mw earthquake of 3rd January 2016, and have a history of experiencing earthquakes of more than 6 Mw which includes 6 Mw 1930, 6 Mw 1953, 6.3 Mw 1880, 6.5 Mw 1939, 6.7 Mw 1950 and 7.2 Mw 1957 earthquakes. The region has high structural complexity and the lack of surficial signatures associated with the earthquakes. The consistency and effects of the regional faults such as the Dauki and Kopili Faults are observed in the Western Manipur Hills vis-a-vis the 6.7 MW earthquake of 2016 that falls under the Barak River basin.

The relation of drainage morphometry and morphotectonic parameters of the Barak River basin with the seismogenic faults needs to be studied. The present study aims to assess the tectono-geomorphic activity in the Barak River basin based on morphometric as well as morpho-tectonic parameters for which the study area was divided into seven sub-basins. Topographic maps and ASTER-DEM data were used for the extraction and calculation of various geomorphic indices such as linear, areal, and relief parameters, Hypsometric integral (HI), and Valley floor width to valley floor height ratio (Vf). The analyzed results are compiled and expressed by applying the concept of a relative active tectonic index (Iat). Fault/ lineament, earthquake, and landslide locations are plotted to find their consistency with the Iat map. The values of it are classified into four classes, namely low, moderate, high, and very high tectonic activity with S/n values >1.98, 1.64-1.98, 1.44-1.64, and <1.44 respectively. This demarcates the study area as having relatively low to very high tectonic activity where sub basin no 6 is highly active (Figure 1). This sub basin has the epicenter of the recent 6.7 Mw earthquake as well as many landslides are present in this sub basin. The recent Tupul Landslide of 2022 is also situated in this sub basin. In this study, systematic analysis of geomorphic parameters using remote sensing data and GIS techniques has not only proved to be useful in evaluating and understanding the spatial distribution of tectonic activities of a landscape, but it has given a better prospect for further assessment of natural hazards and other management and development plans in the basin.