Investigation of Site Properties of the Caldiran (Van, Eastern Turkey) Settlement Area Using Surface Wave and Microtremor Methods

Abstract

Caldiran (Van, eastern side of Turkey) which is a seismically very active region has more than active faults around and the areas under active tectonic effect. The earthquakes and soil characteristics are the significant factors that increase the severity of the damages ratio. For this reason, the characteristics of the engineering structure should be defined accurately and reliably. The shear wave velocity (Vs) obtained from geophysical methods is one of the most important parameters that determine the behavior of the soil during an earthquake. In this study, active and passive source surface wave methods were applied at different measurement points in the study area in order to determine soil properties of the settlement area and its surroundings in Caldiran district the city of Van. As part of this study, 80 boreholes, 95 multichannel analysis of surface wave (MASW) profiles, and 66 microtremor (HVSR) measurements were performed in the study area. The Vs velocity with depth dependent could be determined by using the dispersive behavior of Rayleigh waves in surface wave analysis methods. In order to analyze the engineering characteristic of the region and earthquake-soil-structure relations parameters such as the amplification factor, predominant period (t(0)), Vs velocity, average velocity up to 30 m Vs30, and seismic vulnerability index (Kg) maps have been prepared. In order to reveal the variety of the engineering properties of the area in horizontal and vertical directions, depth cross-sections in different directions were created. When the tectonic structure and regional geology were examined, it was determined that all profile results were compatible with the geological structure.