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Assessment of morphometric parameters for the development of Relative Active Tectonic Index and its significant for seismic hazard study: an integrated geoinformatic approach

Ghosh, Snehasish, Sivakumar, R.
Environmental earth sciences 2018 v.77 no.17 pp. 600
databases, deformation, earthquakes, geological eons, geophysics, hazard characterization, hills, landscapes, morphometry, principal component analysis, rocks, spatial data, surface drainage, tectonics, Himalayan region, India
Earthquake is a geological natural hazard which is shaking of earth’s surface due to seismic activity. The Himalayan region and quaternary geological surface of Indian sub-continent had experienced several earthquakes in the recent geological period due to reactivation of existing faults. Surface drainage system and its morphometric characteristics are controlled by subsurface geo-structural features and active tectonic process which have greater impact on seismic activity. Thus, the present study focuses on the analysis of morphometric parameters for the development of Relative Active Tectonic Index (RATI) and its significant for seismic hazard assessment using geoinformatics. The different morphometric parameters have been analyzed and geospatial databases have been generated. The RATI has been estimated by considering higher priority tectonic influencing parameters based on Principal Component Analysis (PCA) methods and the output has also been integrated with thematic and seismological databases to understand its significance for seismotectonic activity. The result shows that the very high and high Relative Active Tectonic Index are observed in greater and lesser Himalayan sequence, where frequency of earthquake and its magnitudes are also high. The anomalous nature of drainage network, compressed meander in youthful stage, presence of high resistance rocks, structural control on drainage network, relief steepness, and v-shaped narrow valley are the indicator of active tectonics and seismic activity in this region. Even though the foothills micro-basin shows moderate or low Relative Active Tectonic Index, morphometric analysis depicts that it is highly elongated in nature with significant surface tilt and have a greater influence of tectonic deformation. In addition, the continuous stress from Main Frontal Thrust has a significant role for the landscape upliftment and seismic activity in this region. The micro-basin which is located in the quaternary alluvial surface, has not produced any major earthquake in the past, but has greater influence on tectonic activity and may produce earthquake in the future.