Active Tectonic and its Relationship with Volume of the Alluvial Fans (Case Study: Five Basins in North-eastern of Central Iran)

There is a harmonious relationship between the topographic forms of the surface of the earth and hydrologic systems in the geologically active regions. A quantitative estimation between neo-tectonic activities and surface processes is made to formulate and model the evolution of the land perspective. In this study, the alluvial fans of five catchment areas in Sabzevar, Davarzan, Jovein, Safi Abad and Esfarayen in Kavir Markazi (Central Desert) drainage totally amounting to 140 alluvial fans are studied. The parameters of the radius of the alluvial fan(r) and height(h) were calculated using ARCGIS and angle of alluvial fan sweep(s) was obtained using electronic protractor. Then, the volume of each alluvial fan using Church and Giles methods was obtained and linear relationship and the correlation coefficient between the volumes of the alluvial fans(V) and basins feeding them(BA) were set up. In the next step, using geomorphologic indexes, the tectonic activities of the region(Lat) were assessed. The results of this study show that although there is a significant relationship between the volume of the alluvial fan(V) and the area of the upper basin(BA), in the area under study, there is no significant relationship except in Davarzan which has a high correlation coefficient (0.742). There is no relationship between the volume of the alluvial fans(V) and the area of the upper drainage(BA) between two mentioned factors in other areas. Therefore, tectonic plays a basic role in increasing or decreasing the volume of the alluvial fans and the area of the upper basin of the alluvial fans(BA) as a subsidiary element in a way that the alluvial fans of Jovein, Safi abad and Esfarayen are classified of high geologic activities and the alluvial fans of Sabzevar are of medium geologic activities and Davarzan catchment alluvial fans are placed in the class of low geologic activities.