Document Type : Original Research Paper
Authors
1 M.Sc., Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
2 Associate Professor, Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
3 Ph.D., Geological Survey of Iran, Tehran, Iran
4 M.Sc., School of Earth Sciences, Damghan University of Basic Sciences, Damghan, Iran
5 Associate Professor, Islamic Azad University, North Tehran Branch; Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
6 Ph.D., Building and Housing Research Center, Tehran, Iran
Abstract
Depending on their structural maturity, seismogenic faults, , may rupture in one segment or as multiple segments; they also may show different slips on their segments. Mature faults break in long ruptures with small slip, while immature faults rupture as short segments but are more energetic. On the other hand, the mature faults demonstrate clustering pattern in their earthquake recurrence pattern. Also, the ground motions produced by earthquakes on immature faults are larger than those generated by earthquakes on mature faults. In this paper, we defined maturity of major faults in EasternIranseismotectonicProvince, considering their segmentation, rupture length, displacement vector on the rupture and the history of clustered earthquake sequence on the fault. Then, the response spectrum of ground motions caused by large earthquakes occurred on these faults were calculated. To reduce the effect of unknown wave paths, we used ground motions recorded in the near field. Earthquakes of different mechanisms were selected in magnitude range from Mw=5.7 to 7.1. We compared the obtained response spectrum with those resulted from the experimental model presented by Boore et al. (1997). Study of this parameter can help to recognized ground motion potenial of the faults, and considering it in extracting attenuation equations increases the accuracy of the results for seismic hazard assessment. Using our evaluation for structural maturity of the faults, we try to present a model for evolution of seismic activity in Eastern Iran.
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