Iterative Ratio Method: a method to map the depth to the Moho from gravity anomalies

Interfaces characterized by a density contrast are widely distributed in the Earth's interior, and their depths can be recovered by inversion of gravity data. A key parameter of the interface inversion is the density contrast. We propose to estimate a constant density contrast by a new method: the iterative-ratio method. It is based on the approximate invariance of the product between depth and a constant density contrast and on the availability of several depth constraints. The estimated density contrast is used to update the interface depth. By processing the synthetic Moho models, the inversion results show that the method is slightly affected by data noise and by the number of constraints, but it is sensitive to the constraint uncertainty. The method is finally demonstrated by mapping the Moho of the Santos basin (Brazil) according to the depth constraints and the regional gravity anomalies.