Evaluation of seismic site classification for Kahramanmaras City, Turkey

Abstract

This paper presents a study on the seismic site classification map using the geophysical tests in Kahramanmaras city located at a place where African, Anatolian, and Arabian plates meeting in southern-central Turkey. Generating seismic site classification maps in accordance with National Earthquake Hazards Reduction Program (NEHRP) has become a more significant criterion for earthquake hazard estimations. The SPT-N values obtained from the field studies at 287 boreholes within the upper 30 m were used to describe the subsurface conditions in the region. The shear wave velocity (VS) values in the study area were obtained by implementing Multichannel Analysis of Surface Waves (MASW) and Microtremor Array Method (MAM) measurements tests. An approach proposed by Boore (Boore, Bull Seismol Soc Am 94:591–597, 2004) for the cases where the VS measurements do not reach 30 m depth has also been adopted by correlating the shallow shear wave velocity with VS30. The resulting site classification maps estimate that the study area is predominantly classified as soil site class C, while the small areas were rarely classified as soil site class D and B. Furthermore, a systematic analysis based on a comparative study of the present research and the published correlations for seismic site classification with VS30 values has been carried out using Geographical Information System (GIS). Evidently, the VS30 based seismic site classification maps could be effectively used by researchers and engineers for the purpose of land-use planning and urban development in earthquake-prone regions.