New Finding in the Activities of the South-West Zagros Orogeny Belt Mountain by Environmental Factor Case Study : Surmeh Mountain Fars Province, Iran

摘要

In this research, it was attempted to examine the impact of tectonic activities on Surmeh mountain to create the rupture. Surmeh anticline is the most important geological feature of the South-West Zagros orogeny belt in Fars province, Iran. The structure of the rock of Paleozoic-Mesozoic age is complex.Several levels of deformation are probably recognized in the Alpian orogeny. The Alpian orogeny produced folds, low angle thrust, numerous normal faults, a moderate graben and widespread fracture zones. The trend of most faults, folds and fracture zonesis from north-west to south-east. In this county, the main fault is Surmeh thrust. Due to these effects, Dalan formation contains some clay minerals, Marl perch on Dalan formation and beneath it, perch Foraghan formation and Hurmoz series. At the following tectonic phase, the region creates an appropriate condition for salt diapirism, therefore, in the north county, two salt domes can be seen which are called Jahani dome. Although, the Earth scientists believe that in the South-West of Zagros organic belt, the surficial rupture cannot be seen. Due to soft formations such as Hurmoz, Faraghan and Pabdeh-Gurpi which lead to the damping potential of seismic waves, surficial rupture is rarely seen in the South-West of Zagros; that it has been seen in the 1999 Furg earthquake with 6.4 magnitude for the first time and the second rupture has been seen in Khurgu county in 1993 earthquake with 6.7 magnitude and the other place is Ghir, so the most significant factors affecting surficial rupture are : Development and growth of fold-thrust during earthquake, the number of earthquakes with high magnitude (more than 6.4 Richter), the revision of one of the limbs of the folds, being asymmetric folds.