A recovered Moho model by integrated inversion of gravity and seismic depths in Iran

Abstract

This research aims to define the depth of Moho in Iran by collocation method using gravimetric data with seismic information. The definition of the Moho in the Iranian region is of considerable importance due to the geological complexity of the area also characterized by tectonic and orogenic events of particular uniqueness. We applied the collocation method to Moho recovery using the gravity data generated by GOCO03S model reduced by topography/bathymetry, sediment and consolidated crust effects from CRUST1.0. These data have been complemented with seismic Moho depth estimates. A compilation of 213-points seismic depth has been collected over Iran and used in the integrated gravimetric-seismic inversion. Among them, 140 seismic points have been selected completely random and included as data in the integrated collocation approach for Moho depth estimation. The 73 remaining seismic points have been used as checking points for validating the estimated Moho. In the first run, gravity data only have been considered to collocation Moho recovery. When comparing this gravimetric solution with the 73 seismic checking points, a standard deviation of 6.2 km was found. In case of considering the regional seismic depths into the collocation approach, the standard deviation of the residuals between our results and seismic checking Moho depths improved to 4.9 km. It must be stated that, even in the integrated inversion, a significant discrepancy between the seismic and the integrated gravimetric-seismic Moho is present in the South Caspian Basin. Low quality of CRUST1.0 could explain this inconsistency in this area.

Keywords

• Geophysics
• Moho
• Gravimetric inverse problem
• Integrated inversion
• Collocation
• Seismic depths