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.

Using geophysical methods and measuring physical properties of subsurface rocks are good solutions for investigating the subsurface structures and exploring underground buried resources (such as oil, gas, water, minerals, etc.). This research investigates the anomaly sources of Zagros and the Red Sea by using the derivative filters, regularized filters, analytic signal, local-phase filter, 3D-inverse modelling with the Li-Oldenburg method. For this purpose, these filters are first applied to artificial models to determine the capability of each of these filters, a comparisons is also will be made between edge detection filters and finally applied to the real gravity of Zagros and Red Sea regions (taken from the EGM2008 Global Model). The overall result is that the effective depth of the sources of gravity anomalies of the Red Sea is approximately 200 km, and incoherently, up to a depth of 300 km. The effective depth of the Zagros anomalies sources is also about 180 km and since then it has continued inconsistently up to 400 km.