An updated study on near-fault ground motions of the 1978 Tabas, Iran, earthquake (Mw = 7 .4)

This paper presents an updated study and numerical modelling of the tabas, eastern iran earthquake (mw = 7.4), which occurred on september 16, 1978, using new techniques recently proposed by various researchers. firstly, the near-fault ground motions recorded at a station very close to the fault were examined based on the characteristics of the velocity pulses and the frequency content ofthe motions. evidence of directivity effects in recorded, near-fault ground motion, has been investigated using various methods. in the second part of this paper, stochastic simulations of near-fault, strong ground motion, using finite-fault modelling, based on a dynamic corner frequency recently proposed by motazedian and atkinson [motazedian, d. and atkinson, g. stochastic finite-fault modelling based on a dynamic corner frequency, bull. seismol. soc. amer., 95(2), pp. 995-1010 (2005)], have been presented.in order to model the impulsive behaviour of near-fault ground motion, the finite-fault model was combined with the mathematical expression of mavroeidis and papageorgiou [mavroeidis, g.p. and papageorgiou, a.s. a mathematical representation of near-fault ground motions, bull. seismol. soc. amer., 3, pp. 1099- 1131 (2003)] for modelling pulse characteristics. a new set of modelling parameters has been recommended and good agreement has been found between the recorded and simulated response spectra.the velocity pulses observed in near-fault ground motion records could also be mimicked.