Nonlinear and Equivalent Linear Site Response Analysis of Istanbul Soils

Abstract

The effect of local soil characteristics on the propagation of earthquake waves has been commonly studied by researchers. However, the validity of the results obtained by these studies is limited only to the relevant soil conditions. The main purpose of this study is to examine the effect of soil conditions on the propagation of seismic waves in Istanbul. In this regard, soil information belonging to different districts of Istanbul has been compiled. The site response analysis was simulated using a time-domain nonlinear response analysis based on the effective stress method and frequency-domain equivalent linear analysis based on the total stress method. A widely used one-dimensional response analysis program DEEPSOIL was used to estimate the soil response of the sites. Modeled soil profiles were subjected to 1999 Kocaeli earthquake motion and the results of the analysis are presented as spectral acceleration, PGA, and lateral displacements. The results obtained from both of the analyses were evaluated comparatively in terms of the effect of soil properties on the propagation of the seismic waves. The effect of the analysis method based on different approaches on the results is examined. The highlighting results obtained on how the propagation of earthquake waves will be affected by soil conditions. The liquefaction potential of soil profiles was also evaluated using the data of the soil properties of the investigation area.