Evaluation of Fractal Dimension of Fractures and Drainages in Determining the Tectonic Activity of Qameshlu Fault Zone (Northwestern Iran)

Abstract

The study area is located in the northwest of Iran and in the Central Iranian zone (Urmia-Dokhtar volcanic belt). The aim of this study is deretmination of the tectonic activity of the Qameshlu fault. Field studies, evaluation of fractal dimensions and morphometric indices have been used in order to analyze the morphotectonic evidences of the study area. Firstly, the study area was first divided into 18 basins. Then five quantitative morphometric indices including asymmetry factor index (Af), transverse topographic symmetry index (T), stream length-gradient index (SL), Valley Floor Width to Height Ratio (Vf) and Hypsometric integral index (HI) have been calculated. The relative active tectoic index (Iat) is also calculated, in order to determination of amount of relative tectonic activity. This index is divided into three classes, class 1 (high tectonic activity), class 2 (medium tectonic activity), class 3 (low tectonic activity). The quadratic method has also been used to measure the fractal dimension of active faults and streams. For this purpose, the whole region is divided into six boxes and the amount of fractal dimension in each network is calculated using logarithm-logarithm diagram. The results of fractal analysis of faults indicate that section f is the most active part of the study area, while the results of fractal analysis of streams show more tectonic activity in part b. The results obtained from the study of morphometric indices, fractal analyzes and field evidences show more activity in the central part (in the middle of Qomshloo fault) and in the northern and southern parts due to fault density.

Keywords

• fractal analysis
• tectonic activity
• active faults
• fractal
• drainages