The Effect of Active Tectonic of the East Zagros Basin on Formation ofTwin Alluvial Fan of Wazire

Wazire twin alluvial fan is located in the south of Ghatroye town of Nayriz city in Fars province، laying on the basin of Ashegh spring. It is a combination of two alluvial fans، the previous one is older، overlain by new alluvial fan. The present research aims to examine the effects of tectonic on creation of Wazire twin alluvial fan. To this reason، active tectonic in this basin was investigated by means of topographic maps، satellite images and geologic maps and the tectonic situation of the studied area was investigated، using active tectonic indexs: stream length - gradient index، mountain- front sinuosity index، the ratio of valley – floor width to valley height، index of triangle ratio، drainage basin shape ratio، hypsometry integral index. The results of the present research show that، adapting to the faults، stream lengh - gradient index has many alteration at four points. Indexes of mountain – front sinuosity، ratio of valley - floor width to valley height، triangular ratio، drainage basin shape ratio and hypsometry integral were calculated as 1. 08، 1. 6، 1. 79، 1. 7، and 1. 4، respectively. It shows relatively high tectonic activities، which are manifested in the performance of Wazire Fault. Wazire Fault has brought down the hollow of Maidan-e-gell، and consequently has resulted in increase of up-lift rate related to erosion rate، So، twins alluvial fan of Wazire has been created.