Middle East Moho Relief Estimation Using Spherical Prisms in Gravity Inversion

Abstract

Study of Moho in Middle East and surrounding region is of great importance for geoscientists. The area contains parts of the Eurasian, Indian, African and Arabian plates as well as active tectonic structures which made it rich in geodynamic and tectonic interests. In this study we investigated Moho relief in the Middle East region using gravity and seismic data. Regarding the extent of the study area, spherical prism (tesseroid) modeling is used to calculate the gravity effect of the topography and crustal anomalies. Determining of Moho depth from gravity data is a nonlinear inverse problem. We inverted the gravity data using Uieda’s inversion method where the process was constrained by the available seismic data over the study region. The effect of topography and crustal sediments were excluded using global topography and crustal models. The resulting Moho relief is in accordance with plate boundaries and correlates well with the prominent tectonic features of the Middle East region. According to the results, the thinnest part of the crust found to be about 12 km in the Indian Ocean and the thickest part appeared in the west of Tibetan plateau with depths of about 54 km. In some parts of the study area discrepancies were seen between our results and Moho depths from seismological studies these differences are most probably caused by different approaches used in the different studies. Since we imposed smoothness by regularization on estimated Moho map, this can also be additional source of the discrepancies.