The application of geophysical and fractal methods in the identification of alluvial sediment faults in Derkeh area of Tehran

Jahanbin, Mohsen; Mehrnia, Seyyed Reza; Shirvani Mahdavi, Hamidreza; Rahimi, Habib

doi:10.22034/irqua.2020.702377

The application of geophysical and fractal methods in the identification of alluvial sediment faults in Derkeh area of Tehran

Document Type : Original Article

Authors

Mohsen Jahanbin ¹

Seyyed Reza Mehrnia ²

Hamidreza Shirvani Mahdavi ³

Habib Rahimi ⁴

¹ Department of Petroleum, Mining and Materials, Faculty of Civil Engineering and Land Resources, Tehran Branch, Islamic Azad University,Tehran, Iran

² Department of Geology, Payam Noor University, Tehran, Iran

³ Department of Physics, Tehran Branch, Islamic Azad University, Tehran, Iran

⁴ Engineering seismology, University of Tehran, Tehran, Iran

https://doi.org/10.22034/irqua.2020.702377

Abstract

The main purpose of this research was to identify the faults in Derke area of Tehran. For this purpose, geoelectrical profiles with Wenner-Schlumberger array, ground penetrating radar (GPR), and the diffraction-distance exponential function were used for the fractal measurement of the geoelectrical profile. In the conducted field visits, fractures and faults with different lengths were detected in large areas of rocks in the region. North Tehran fault is the most important and influential fault in the studied area. Among other sub-faults in the region, we can mention Imamzadeh Daoud, Darband and Shirpala faults. The results of geoelectric profile processing show a very strong drop in specific resistance at the distance of 96 meters of the profile due to the existence of a fault zone. The minimum changes of specific electrical resistance under the fractal method shows a linear trend with a relative drop in the fractal dimension. In some areas, an unusual increase in the fractal dimension and the creation of chaotic conditions indicate faulted and fractured areas. Also, the changes related to the sharp drop in the amplitude of electromagnetic waves in the GPR radargram at distances of 90 to 100 meters confirm the existence of a fault zone in the studied area.

Keywords

Wenner array

fractal dimension

ground penetrating radar

Schlumberger

North Tehran fault