Application of noise wavefield to assign velocity model in site effects studies- A case study in Tehran

Analysis of seismic ambient vibrations is becoming a widespread approach to estimate the profile of subsurface shear wave velocity. In this paper we are going to show the basic concepts of one most useful ambient noise array processing, Spatial Autocorrelation (SPAC) method and its application in a site in south of Tehran. The previous site effect estimations on this site using the earthquake records [6] show an important amplification surprisingly beginning at the very low frequencies. To explain this unexpected results, in contrast to the results of 1D analytical method of previous studies try to find the Vs profile of the studied site by applying ambiant vibration array measurements to better understand the effect of surface geology on the seismic motion.

Keywords:

Site effect , Velocity model , Seismic noise , Tehran