MICROZONATION OF A LARGE CITY WITH RESPECT TO PGA AND SAFE PERIOD OF BUILDINGS

A method for microzonation of large cities is presented based on a probabilistic concept. It uses the elements of seismic hazard analysis in microzoning a region,This method is useful where enough earthquake data or no data is available. Two different types of mierozonation are presented namely, (a) microzonation based on the probability of exceedence of a certain PGA level, and (h) microzonation based on the probability of exceedence of a certain design PGA values, The method of microzonation also takes into account the effect of local amplification of earthquake due to soil conditions. It further recommends periods of structures not to be constructed in each microzone . A ۷۵ kinx۷۵ km region surrounded by three point sources of earthquake is taken as an illustrative example for the application of the method proposed here.