Analog modelling of active faults in Tehran

Executor of project: Dr. Morteza Talebia

2015 

The capital city of Tehran is located in south of central Alborz. The North Tehran fault, as the main structure of this region, perched on the northern part of the city and separate alluvium fans from volcanic rock of the Alborz. There are several other faults within the city which seem to be structurally related to the north Tehran fault. Geomorphic study of fans and river deposits suggest that most of these faults are active and taking up both left-lateral and shortening in a wider zone to the south of north Tehran fault. In addition to faults there is distinct folding within the Tehran plain. Field observation along road cuts which cross these structures suggest that young folding in Tehran's plain are active and escalate due to the activities of the underlying faults. There is little evidence of rupture in front of these structures and thus most of them are considered as blind faulting. The trend of these structures is oblique to the North Tehran fault which is probably due to distribution of left lateral deformation in wider zone within the Tehran plain. The distance between active folds and the North Tehran fault increase from west to east. Analog modeling was carried out to study the effect of thickness and slop of deposits on position and trend of structures within the Tehran plain. Results from these experiences show that geometry, orientation and distance between structures is probably controlled by oblique shortening of the zone, as well as increase in thickness and slope of the sedimentary deposits.