The aim of this study is the geomorphological analysis of neotectonic deformation in the Avaj region in the NW part of the Iranian Plateau. We use observations from detailed field surveys and the analysis of digital e...The aim of this study is the geomorphological analysis of neotectonic deformation in the Avaj region in the NW part of the Iranian Plateau. We use observations from detailed field surveys and the analysis of digital elevation model(DEM) and satellite images(Landsat-7 ETM+, 30-m resolution) to explore a new E-W trending strike-slip fault system in the study area. The major active faults of the Avaj region are the NW-SE trending Avaj and Hassanabad fault zones. The Avaj Fault is a SWdipping reverse fault with a transport toward NE and the Hassanabad Fault is a NE-dipping reverse fault that has moved Paleozoic rocks over Cenozoic sedimentary units. Moreover, there are some E-W trending left-lateral strike-slip faults which cut Late Quaternary deposits. The relationship between the NW-SE and E-W faults indicates that the slip at the termination of the NW-SE faults changes from reverse to left-lateral strike-slip faults. The activity of the left-lateral faults has formed a series of offsets and displacements in drainage paths. These left-lateral faults probably initiated in 5±2 Ma because of the convergence between the Central Iran and the South Caspian blocks.展开更多
The Alborz Range,northern Iran,is a chain of mountains along the southern side of the Caspian Sea.This mountain range shows strong tectonic activity with several destructive earthquakes in the past.The range is tecton...The Alborz Range,northern Iran,is a chain of mountains along the southern side of the Caspian Sea.This mountain range shows strong tectonic activity with several destructive earthquakes in the past.The range is tectonically active,and the seismicity record shows both range-parallel left-lateral and thrust faulting.Tehran the capital of Iran and one of the largest cities in the world is located in the foothill of the Alborz Mountains,which is at risk of seismic hazard.This study is mainly focused on a scarp that passes by west of the Qarchak(a suburb in south east of Tehran)and therefore it is called the West Qarchak Fault.So,geological and geophysical surveying method was applied to study the West Qarchak Fault which is continuous and reaches to Pishva Fault in south east(with same trend)and crosses the Kahrizak Fault in the north west.In conclusion,it can be seen that apparently the geometry of the West Qarchak Fault is normal but the real mechanism is reverse(based on subsurface investigation).Morphologically,the Kahrizak Fault scarp has some similarity to the West Qarchak fault and it can be said that the geometry and mechanism of the Kahrizak Fault is same as the West Qarchak Fault,but requires a more detailed study.展开更多
文摘The aim of this study is the geomorphological analysis of neotectonic deformation in the Avaj region in the NW part of the Iranian Plateau. We use observations from detailed field surveys and the analysis of digital elevation model(DEM) and satellite images(Landsat-7 ETM+, 30-m resolution) to explore a new E-W trending strike-slip fault system in the study area. The major active faults of the Avaj region are the NW-SE trending Avaj and Hassanabad fault zones. The Avaj Fault is a SWdipping reverse fault with a transport toward NE and the Hassanabad Fault is a NE-dipping reverse fault that has moved Paleozoic rocks over Cenozoic sedimentary units. Moreover, there are some E-W trending left-lateral strike-slip faults which cut Late Quaternary deposits. The relationship between the NW-SE and E-W faults indicates that the slip at the termination of the NW-SE faults changes from reverse to left-lateral strike-slip faults. The activity of the left-lateral faults has formed a series of offsets and displacements in drainage paths. These left-lateral faults probably initiated in 5±2 Ma because of the convergence between the Central Iran and the South Caspian blocks.
文摘The Alborz Range,northern Iran,is a chain of mountains along the southern side of the Caspian Sea.This mountain range shows strong tectonic activity with several destructive earthquakes in the past.The range is tectonically active,and the seismicity record shows both range-parallel left-lateral and thrust faulting.Tehran the capital of Iran and one of the largest cities in the world is located in the foothill of the Alborz Mountains,which is at risk of seismic hazard.This study is mainly focused on a scarp that passes by west of the Qarchak(a suburb in south east of Tehran)and therefore it is called the West Qarchak Fault.So,geological and geophysical surveying method was applied to study the West Qarchak Fault which is continuous and reaches to Pishva Fault in south east(with same trend)and crosses the Kahrizak Fault in the north west.In conclusion,it can be seen that apparently the geometry of the West Qarchak Fault is normal but the real mechanism is reverse(based on subsurface investigation).Morphologically,the Kahrizak Fault scarp has some similarity to the West Qarchak fault and it can be said that the geometry and mechanism of the Kahrizak Fault is same as the West Qarchak Fault,but requires a more detailed study.
