From a GIS-based hybrid site condition map to an earthquake damage assessment in Iran: Methods and trends

Abstract

From several decades ago, the average shear wave velocity for the top 30m (Vs30) has been proposed as one of the important factors that reflects the amplification behavior of a site. Most of seismic design standards such as National Earthquake Hazards Reduction Program in the United States and Standard No. 2800 in Iran emphasize on the use of Vs30 measurements for site classification according to the soil type. As an important step in profound seismic risk reduction to earthquakes, a site effect study was conducted at a nationwide scale. We followed an indirect method to produce Vs30 map of Iran from geological and topographical data. The outputs indicate that hybrid Vs30 map has better performance than single topography-based Vs30 map. The amplitude map deduced from Vs30 and geology maps then is used for seismic microzonation of Tabriz city and extent of geographical distribution of damage for a possible deterministic scenario (M=7) is investigated through considering different fragility curves to describe damaging behavior of ordinary building types in the city.