Probabilistic microzonation of urban territories: A case of Tashkent City

The problem of accounting for local soil effect on earthquake ground motion is especially urgent when assessing seismic hazard - recent needs of earth quake engineering require local site effects to be included into hazard map s. However, most recent works do not consider the variety of soil condition s or are performed for generalized site categories, such as "hard rock." "s oft soil" or "alluvium." A technique of seismic hazard calculations on the basis of the Fourier Amplitude Spectra recently developed by the authors al lows us to create hazard maps involving the influence of local soil conditi ons using soil/bedrock spectral ratios. Probabilistic microzoning maps may be constructed showing macroseismic intensity, peak ground acceleration, re sponse and design spectra for various return periods (probability of exceed ance), that allow optimization of engineering decisions. An application of this approach is presented which focused on the probabilistic microzoning o f the Tashkent City.