the uncertinity in seismic risk assessment in near-fault area

In the near-fault area, two special features referred to as forward directivity and static deformation cause the directivity and fling pulses with long period and high amplitude, respectively. the conditions for occurrence of directivity pulse are much more common than the fling pulse, which is appeared in a limited distance very close to the fault (almost 1 km). meanwhile, the directivity pulse can be observed with large peak up to approximately 15 km from the causative fault depending on the earthquake magnitude. these pulses can seriously affect structural response and induced damage. therefore, the vulnerability of buildings in the cities situated close to the active faults needs to be carefully treated. in the most cities in iran like tehran and karaj, many regions are closely located to the active faults. this will raise an importantquestion that the available fragility curves are good enough to accurately estimate buildings vulnerabilities for the motions including directivity or fling pulses.