Tectonics
Mohammad Hossein Tahriri; Hamid Saffari
Abstract
The Doruneh fault system with more than 700 km length, after the main Zagros fault, is known as the largest fault in Iran. In this research, this fault system is divided into 3 main parts because the mechanisms of its different parts are different. The western part is reported to have a left lateral ...
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The Doruneh fault system with more than 700 km length, after the main Zagros fault, is known as the largest fault in Iran. In this research, this fault system is divided into 3 main parts because the mechanisms of its different parts are different. The western part is reported to have a left lateral strike-slip mechanism with a reverse component, the middle part is a left lateral strike-slip mechanism, and the eastern part is reported to have a reverse mechanism. In this study, seismicity parameters and their temporal and spatial changes along this fault system are analyzed using seismic data collected from 1980 to 2023 and based on the maximum likelihood method. In this regard, the temporal changes of b-value shows two significant drops, which indicate two relatively strong Torbat-e Heydarieh earthquakes in 2010 and the Fariman earthquake in 2017. Despite the fact that the scientific community is not yet able to accurately predict earthquakes, according to the studied method and with the continuous monitoring and analysis of various earthquake parameters, especially b-value, it is not far from expected to predict the occurrence of possible earthquakes in the future.
H Amini; M Fattahi; M.R Ghassemi
Abstract
The Doruneh fault is the second longest fault systems in Iran. This fault is 700 km long and extended from the Afghanistan-Iran border to the central Iran desert. Despite of its length, and position in the convergence zone between the Arabian and Eurasian plates and its seismic potential, only one historical ...
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The Doruneh fault is the second longest fault systems in Iran. This fault is 700 km long and extended from the Afghanistan-Iran border to the central Iran desert. Despite of its length, and position in the convergence zone between the Arabian and Eurasian plates and its seismic potential, only one historical earthquake (M>7) and two instrumental (M>6) earthquakes are recorded on this fault. Therefore, study of this fault is very important for evaluation of its seismic hazard. In our study, we used the Landsat images, aerial photographs, topography maps, geological maps and field work data to identify and estimate the amount of displacements of rivers, rock units, and some alluvial fans along this fault. Three branches of the Doruneh fault investigated in this study, named as the north, middle and south branches according to their geographical locations. This study demonstrates that both of the maximum and minimum fault displacements have occurred on the southern branch. Furthermore, the amount of displacements of the rivers, which have cut the alluvial fans during the Quaternary period, suggests that this branch, particularly between 57˚00΄ and 58˚50΄E, is more active than the other branches. Although, several slip rates were previously determined using different methods for some parts of this fault by the authors and other researchers, we suggest further dating and geodetic methods in the same regions and other part of the fault to estimate and compare the slip rate of different branches of this important fault.
H. Amini; M. Fattahi; M. R. Ghassemi
Abstract
Doruneh is an active left- lateral strike- slip fault in North-East Iran. Surface trace of this fault is about 700 km long, and cuts across Quaternary and Tertiary deposits. In some places along the fault, sediments of Paleogene. Neogene, and alluvial fans of Quaternary age are displaced ...
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Doruneh is an active left- lateral strike- slip fault in North-East Iran. Surface trace of this fault is about 700 km long, and cuts across Quaternary and Tertiary deposits. In some places along the fault, sediments of Paleogene. Neogene, and alluvial fans of Quaternary age are displaced by the fault. Left- lateral displacement between 91-457 m are evident in Landsat images between east of Beiragh and east of Khalil-abad. Displacements are also evident in streams that are incised over the above mentioned deposits. We have tried to estimate the recent history of activity on the fault on the basis of the measured displacements and estimated slip rates of the fault. Estimated age of left- lateral movement inception on the fault is very much younger than the displaced geologic units. These observations indicate that Doruneh Fault has been mostly active during the last few millions, which in turn proves the fault to be an active structure.
