Seismic Loss Assessment of Residential Buildings in Karaj, Iran, By Considering Near-Source Effects Using Stochastic Finite-Fault Approach

Abstract This study provides the results of a study conducted to evaluate the seismic loss of residential buildings in Karaj, Iran, caused by the rupture of North Tehran Fault (7.1 Mw). One of the main concerns of seismic risk assessment in Karaj is proper considering the near-source effects of the NTF fault, which passes through the city. In the present study, the finite-fault approach with dynamic corner frequency was first employed to simulate the acceleration time histories. This is an appropriate approach to take into account the source, path effects, directivity and site condition on seismic waves. The results of seismic hazard showed that the PGA values vary between 0.15 to 0.55g, with maximum values nearby the NTF fault. Afterwards, a high-quality database of residential buildings consists of 26 building types was compiled. A set of compatible vulnerability curves were also employed. The results indicated that the loss ratio, defined as the ratio of the loss to the total exposed economic value, for the whole of Karaj is about 18.2%±5.3. The northern parts of the city, which are close to the NTF fault, are the most vulnerable. A disaggregation analysis was also performed to identify the most vulnerable building types. The results showed that the adobe and low-quality masonry buildings contribute the most to loss. The findings from this study can be used by local authorities and managers to provide appropriate emergency and risk reduction plans in Karaj in the case of the NTF fault seismic scenario.