Modeling of Isparta basin structure with geophysical methods and preparation of scenario earthquake seismic hazard maps

In this study, it is aimed to reveal earthquake hazard intensity distribution of fault segments affecting Isparta basin south of Isparta angle using scenario earthquake simulation. Primarily, for this purpose, ReMi, seismic reflection and gravity method have been used as geophysical methods in order to reveal the soil properties and bedrock depth distribution of Isparta basin. The ground classification was made according to the National Earthquake Hazards Reduction Program (NEHRP) using the slip wave velocities (Vs) obtained from the Remi study at 152 points. The inside and edge of the basin, composed of pyroclastic material and quaternary alluvial deposits, are defined by D and C ground groups. Seismic reflection and gravity method are used comparatively to reveal the depth distribution of the bedrock in the study area. In the seismic reflection method performed at 200 CDP (Common Depth Point) on two profiles with a total length of 3.2 km, the western edge depth of the basin is determined as 142 m and the eastern edge depth is 194 m. The depth distribution of the basin bedrock was determined by gravity method, which is carried out with a grid interval of approximately 1.2 km at 108 points. Within this context, the highest alluvial deposit thickness in the Isparta basin is 511 m. The bouguer gravity data collected by the MTA were used to generate the main rock depth distribution of the simulation area. The results obtained from geophysical methods are entered as field data for scenario earthquake simulations. In the scenario earthquake simulation, 3-D Elastic Seismic Wave Propagation Code (E3D) was used. In the simulation, 3 October 1914 Burdur (Ms = 7.0) earthquake, 12 May 1971 Burdur (Ms = 6.0) earthquake on the Fethiye-Burdur fault zone and 1 October 1995 Dinar (Ms = 6.2) earthquake on the Dinar-Çivril fault, which are effective on the Isparta basin, were considered. Different rupture states of finite fault segments which are forming these earthquakes are modeled. In addition, 24 August 2014 Ağlasun (Mw = 5.0) point-source mechanism earthquake was modeled. Seismic hazard intensity distribution of Isparta basin is investigated with 10 different scenarios in total. As a result of scenario simulation of the 1914-Burdur NE directional single-sided fracture model, it is predicted that the highest ground speed (Peak Ground Velocity, PGV) will be 36 cm / sec and the instrumental intensity will be close to VIII.