GIS Based Evaluation Of Relative Active Tectonics From Geomorphic Indices And Morphological Indices In Assam-Arakan Valley

Abstract

There are shelves, slopes, and basins in the sedimentary part of Assam-Arakan valley. The Dhansiri valley, which is situated among the Naga foothills and Mikir hills, and the Brahmaputra valley are both covered by the shelf portion of the basin. The shelf extends westward from the Digboi to the Shillong plateau's southern slope. Beneath the Naga schuppen belt is the hinge zone, or shelf-to-basinal slope. To estimate the relative index of active tectonics (RIAT) for the Assam region, many aspects of geomorphic analysis, such as hypsometric integral (HI), stream length (SL) gradient, basin form (BS), and valley floor (VF), have been utilized. When it comes to financial investments for hydrocarbon exploration from such terrains, tectonic (in)stability is a big worry. Landform deformation brought on by seismic frequency has a significant impact on the pattern of drainage basins and drainage anomalies, which in turn affect the pattern of distribution of floods. In order to classify the tectonic events that are leading to influences the geomorphic/morphometric indices and drainage pattern for the Assam valley are obtained. Such parameters can be estimated by using GIS based toolkits. The indices are categorized into three groups depending on tectonic activity (TA), and the relative active tectonics index (IRAT) is produced by averaging the classes. The four IRAT classes—extreme (1.57–1.80 as Class 1), high (1.81–2.06 as Class 2), moderate (2.07–2.26 as Class 3), and low (2.27–2.30 as Class 4)—are the ones that are defined for this research. The majority of the research area, according to the results, is located in extreme to moderately active tectonic regions, and these regions are congruent with large thrusts and faults that are exist in the basins. The identification of distorted landforms resultant from active tectonics is made possible by the integrated method of GIS-based geomorphic/morphometric assessment. The outcomes can also be used to create sustainable terrestrial usage development and watershed management.