A Comparative Analysis of Evolutions of Tectonical activities in Banks of Hable, Jajrood, and Haji Arab Rivers through Morphometric Methods

The study of active tectonic is significant due to assessment of the risk of earthquake in different areas, especially those where relatively high tectonic activity was observed in Holocene and Pleistocene. The objective of present study is to compare the tectonic activity levels in banks of Hable, Jajrood, and Haji Arab rivers through morphometric analyses. The ratios determined in the present study include the proportion of valley floor width to its height, mountain front-side sinuosity, and longitudinal slope of river, drainage basin asymmetry, and ratio of drainage basin shape, ratio of inverse topographic symmetry of the basin, ratio of drainage basin symmetry, and symmetry ratio of the basin all of which represent the tectonic activity of a region in four categories of low, medium, high and very high. For active tectonic estimation, topographic maps (1: 250,000 and 1: 50,000) along with geological maps (1: 20,000 and 1: 25,000) along with 10m DEM of the studied regions were used. For generation of basins on the studied region, ArcGIS Software was used to deal with a database of digital elevation model. Certain phenomena such as fault scarp, multi-generational alluvial fans, and linear valleys are among morphologic evidence that are abundantly found in basins with high and medium tectonic activity. The results suggest that among the examined basins, the Jajrood basin is more influenced by tectonic activities and this is due to the influence of Jajrood Fault on this basin.