Fault determination due to sinkhole array on Lar Valley, northeast of Tehran (Iran)

Abstract

The main objective of this paper is to present an approach to identify active faults in karstic enviroments. This is achieved by a releasing relationship between sinkholes or dolines formation, array and active faults mechanism. In this research, Lar valley on the Northeast of Tehran, Capital of Iran was selected as a case study. The sinkholes array in the valley shows that their formation and location is influenced by active faults. As a result of active faults mechanism, a number of young and old dolines have been formed on north and south of the study area. According to Aerial Photographs, Satellite images and geological logs corelation three major active faults were distingushed in the study area specially under Lar dam structure. Two of the faults are elongated to the north and the one extends to the south, seven sinkholes were formed on faults. Based on the available evidences, it is assumed that the formation and array of dolines in the study area has been formed and controlled by active faults. Conversely, it is deduced that faults activity may be determinated by sinkholes formation and array. This results may be applied for the similar cases of world's karstic belt.