Evaluation of Seismic Hazard and Site Geodynamic Properties by Using Geophysical Methods in the North of Iran

Abstract

In this study two powerful geophysical methods are used in order to evaluate the properties of shallow soil deposits at a specific area for planned power plants construction purposes. Twenty five seismic refraction survey lines were conducted at the study area to record the vertical movements of the ground. The acquired shot gathers were processed and then the information of primary wave (P-wave) and shear wave (Swave) velocities derived. The P-wave velocities were obtained by using the Seismic Refraction Tomography method (SRT) while the S-wave velocities were extracted by utilizing the Multichannel Analysis of Surface Waves (MASW) technique, which is established based on Rayleigh waves dispersion characteristics. The resulted wave velocities information used to predict the seismic hazard level and dynamic behavior of the soil and bedrock layers. By this information the assessment of site characterization was carried out. The obtained results show that the western central and southern central parts of the area are characterized by less competent soil layer quality whereas elsewhere are specified by more competent soil deposits and less hazard risk for any engineering purposes.