Investigation of a sedimentary basin by using gravity and seismic reflection data in the Isparta basin, southwestern Turkey

The Isparta sedimentary basin is situated in the west Anatolian tectonic region and is surrounded by many active faults that are capable of producing destructive earthquakes. Due to the trapping of the seismic waves, such a basin could increase the magnitude and duration of earthquakes. Therefore, in estimating the earthquake hazard, the investigation of the alluvial accumulation and the bedrock depth geometry may play a vital role. The gravity method was used as the primary method and the measurements were carried out at 108 locations in order to investigate these properties within the Isparta basin. For the basin modeling, in addition to the gravity data, seismic reflection data were collected along two profiles (SRP-1, 84 CDP and SRP-2, 96 CDP) and borehole data compiled from the basin were used as supportive data. The 3D bedrock distribution map of the basin was obtained by using the gravity data and interpreted considering the obtained seismic reflection sections and borehole data. The deepest bedrock depth of the basin was determined to be about 510 m. Furthermore, the horizontal gradient (HG) and Euler deconvolution were obtained by using the gravity data for analyzing the lineaments in the basin. The results of the horizontal gradient and that of Euler deconvolution (SI:0) were compatible with each other. The depth distribution of bedrock and the fault lineaments are the factors that directly affect the seismic hazard. Therefore, it is expected that the results of this study will provide important data for determining the seismic hazard design.