Coda wave attenuation in the Zagros collision zone in southwest of Iran and its tectonic implications

The Zagros collision zone, located in the southwest of Iran, is experiencing an immoderately large number of seismic hazards caused by the convergence between the two Arabia and microplate of central Iran. The coda Q has been widely used as a vital parameter to investigate the different tectonic features as well as seismic risk assessments. In this study, we have analyzed the spatial variation of coda wave attenuation in the Zagros region, to evaluate different geological features affecting the seismic wave's propagation. Our dataset comprises 87,295 coda records of about 6421 local earthquakes, with magnitude greater than three recorded by 36 seismic stations in the period of 2006-2020. We have applied a very simple Qc\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Q_{c}<^>{{}}$$\end{document} regionalization method to mapping spatial distribution of Qc\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Q_{c}<^>{{}}$$\end{document} in Zagros area. The spatial distributions of coda have a positive correlation with the tectonically and lithology of the interested area. According to the results, three primary elements have been suggested as major controlling factors of variation of seismic Coda waves in different parts of the Zagros area. These factors include: (1) intra-crustal relamination process (crustal channeling), (2) 12 km thickness of sediment-filled by fluid (oil and gas) and (3) Hormoz salt (salt domes). Our results of coda wave attenuation, coupled with the findings from 3D velocity tomography which revealed significant velocity variations across the Main Zagros Reverse Fault (MZRF), particularly toward the Sanandaj-Sirjan zone, suggests a potential influence of the fault zone on seismic wave propagation characteristics.