چكيده به لاتين
Abstract:
Seismological engineers estimated earthquake intensity over many years by probabilistic seismic hazard analysis. In predicting seismic hazard analysis, the effects of earthquake directivity on near faults area are not considered, and predictive models must be presented to apply these effects. On the other hand, the great Tehran area with significant faults in the suburbs and sometimes inside the city has the potential for experiencing large earthquakes with the directivity effects.
In this study, we first propose predictive models of directivity effects and probability models based on three-dimensional geometry parameters of the fault and the site, then we adapt this model to the Tehran region. This model includes the most reliable model of forward and backward rupture direction, and also covers the effects of the average slip of the fault plan (rake) and the slip due to point of the Hypocenter. In the further research, using the proposed compatible models of the region, we have carried out a near fault probabilistic seismic hazard analysis with regard to the directivity effects of the city of Tehran. In this regard, we have adopted the maximum directions of spectral acceleration for the city of Tehran. Which is roughly to the north. On the other hand, the ratio of the earthquake intensity obtained for Tehran region in two returns period was investigated. The results of this section show that, as the natural period increases, the spatial acceleration due to directivity increases also, and on the other hand, with the increase of the return period, the ratio are increase.
Finally, the results of this study provide spectral accelerations for the return periods of 475 and 2475 years which have been plotted for intervals of 0.2 to 3 seconds as Isomaps and the spectral acceleration ratio due to probabilistic seismic hazard analysis Conducting the directivity effects without considering the directivity effects is also provided that the researchers of this study can obtain these ratios for different regions of Tehran.
Keywords: probabilistic seismic hazard analysis, earthquake directivity effects, probability due to presence of pulse, near-fault region
