The Relative Tectonic Activity Evaluation of Some River Basins Developing on a Fault Line: The Case of the Ganos Fault (Tekirdað)

River systems are one of the important indicators of crustal deformation in tectonically active areas. This is because; tectonic activity mostly determines the general character of valley morphology and drainage in such areas. In this regard, the relative effect of tectonic activity on topography has been evaluated more precisely in recent years through studies based on digital measurements that employ various morphometric parameters (geomorphic indices). The present study aims to make a tectonic evaluation of some river basins on the Ganos Fault based on morphometric parameters used in determining relative tectonic activity. This study, which aims to determine relative active tectonic effect value, includes the topographic symmetry factor (T) in analysis as distinct from previous studies. The digital elevation model (DEM) data obtained by using the related map sheets of Turkey’s topographic maps and different thematic maps of various sizes are used as basic materials. In the present study, measurements were conducted, and thematic maps were created by use of GIS (Geographic Information Systems) techniques. It was concluded that more than half of the area (56 %) involves very high (class 1) relative tectonic activity, and the average value is 1.99 (class 1) in the area. This finding proves that the area contains very high tectonic activity. The findings of the present study are consistent with previous geological and geomorphological studies carried out in the area. The research method used in this study may allow determining the areas exposed to high level deformation associated with active tectonics. Most importantly, the results of this study show the areas where different kinds of ground-origin natural disasters may take place, earthquake being in the first place. Furthermore, it was realized that research for determining tectonic activity based on morphometric parameters by use of GIS techniques yields clearer and more accurate results.