The comparison of the divergent and convergent tectonic plates margins seismicity – the case study: Red Sea and Zagros

Ali AMJADI; Bahram AKASHE; Mohammad ARIAMANESH; Mohsen POURKERMANI

doi:10.31577/congeo.2020.50.2.5

Ali AMJADI Department of Geophysics, North Tehran Branch, Islamic Azad University, Tehran, Iran
Bahram AKASHE Department of Geophysics, North Tehran Branch, Islamic Azad University, Tehran, Iran
Mohammad ARIAMANESH Department of Geology, Payam Noor University, Tehran, Iran
Mohsen POURKERMANI Department of Geology, North Tehran Branch, Islamic Azad University, Tehran, Iran

DOI: https://doi.org/10.31577/congeo.2020.50.2.5

Keywords: Zagros, Red Sea, focal depth, magnitude-frequency relation, focal mechanism

Abstract

Regarding the seismicity of the Zagros and the Red Sea regions, the present study has investigated and analyzed the seismicity with M ≥ 5 of these regions with obtaining seismicity coefficients, geometrical characteristics including depth, earthquake dispersion and focal mechanism of earthquakes, and their relation to each other. The estimated b-value for these two zones is approximately the same, being equal to ∼1.2. However, the total number of earthquakes in the Zagros is much higher (approximately 5.5 times), when the ratio of small to large earthquakes is about the same amount. In this study, focal depth of more earthquakes occurred and located in the Zagros and Red Sea respectively in depth of 15–20 km and 10–15 km from the earth surface, indicating that the Zagros Crust is thicker than the Red Sea.