Probabilistic Seismic Hazard Analysis of the Area of Tajikistan Applied to Seismic Design

Abstract

In current Probabilistic Seismic Hazard Analysis we analyzed an area and fault models. Shallow crust and deep earthquakes are occurred in the area of Tajikistan, and used two area models for shallow earthquakes and one area model for the deep earthquakes. Additionally, we used so called “Woo’s model” or “point model” which is based on the past seismicity more directly. Six active fault databases for Central Asia and specifically for Tajikistan were used to create the fault model.Software CRISIS2015 and recent Ground Motion Prediction Equations were used in the computation. A grid with 0.1 degree of latitude and 0.1 degree of longitude covered the study area, was created for calculations, and for each 9744 grid points we calculated the spectral accelerations from 0.01 s (PGA) to 3.0s, and for 5 exceedance probabilities in 50 years.For easy application of the results in seismic design, all calculations were made for three values of Vs30, corresponding to 3 categories of the soils in the existing Seismic Design Code in Tajikistan.Special 15 Excel sheets were created for engineers and designers to easy construct the uniform hazard spectra for three types of soil conditions for needed points and exceedance probabilities.