A quantitative analysis of relative tectonic activity classes of Kali river basin, southwest coast of India

The Kali river basin of the southwest coast of India has been investigated to examine the influence of tectonic activity through an analysis of the geomorphic indices that were computed using geographical information system (GIS). Five geomorphic indices—stream length–gradient index, asymmetry factor, hypsometric integral, valley floor width-to-height ratio, and elongation ratio—were used for identification of evidences of tectonic activity. The results obtained from these indices were combined to develop an index of relative tectonic activity classes using GIS. The average of the five measured geomorphic indices was used to evaluate the distribution of relative tectonic activity in the study area. About 18 % of the study area (～726 km²) belongs to class?1; 37 % (～1506 km²) to class?2; and 44 % (～1,762 km²) to class 3. Sub-basins found at the Western Ghat region, relative tectonic activity classes show low and medium values which indicate the higher degree of tectonic activity compared to the upland plateau regions.