Acceleration response spectra for Tbilisi city with site effects

Abstract

The utilization of time histories of earthquake ground motion has grown considerably in the field of earthquake engineering. It is very unlikely, however, that recordings of earthquake ground motion will be available for all sites and conditions of interest. Hence, there is a need for efficient methods for the simulation of strong ground motion for a given region. Due to lack of the real strong ground motion records the objective of this research is to develop a methodology for rapid generation of horizontal and vertical components of earthquake ground motion at any site for Tbilisi city. The model developed in this study provides simulation of ground motion over a wide range of magnitudes and distances at 8 earthquake sources zones of Tbilisi region (within 50 km). The research includes three main topics: (i) the stochastic simulation of earthquake ground motion at a given site of the city of Tbilisi; (ii) the estimation of acceleration time histories at a given site using the direct method of engineering seismology considering soil conditions based on the theory of the reflected waves and (iii) calculation of horizontal and vertical acceleration elastic response spectra for main sites of Tbilisi territory. The simulation procedure typically consists of multiplying deterministic modulating function with a stationary process of known power spectral density. The obtained results in the terms of normalized elastic response spectra can be widely applied in the practice of earthquake engineering in Georgia.