Moho geometry beneath northern Algeria from gravity data inversion

Abstract

The aim of this study is to provide a Moho geometry model for northern Algeria where the few studies that have been carried out concern only restricted areas. The method we used is based on the 3D inversion of the Bouguer anomaly data computed by the Bureau Gravimétrique International (BGI) from satellite data.The proposed Moho depths are roughly comparable to those obtained by previous studies conducted in the NE of Algeria, central part of the Saharan Atlas and according to a NNW-SSE profile from the coast to the Saharan platform. The results we obtained have been also compared to those from more detailed studies conducted in the Betics and Morocco, enabling us to validate the proposed model. The Moho depth accuracy which has been investigated through the variation of the density contrast and the initial depth shows a maximum error of ±2.8 km. The main results of this study indicate that the lowest Moho depth (~11 km) is observed in the Algerian Basin and thereby the crust thickness is of about 8 km, while the highest (~34 km) corresponds to the Saharan Atlas and the Aurès and Hodna Mountains. Along the coast, the depth of the Moho is about 25 km and increases towards the south to reach 30 km at the southern boundary of the Tell Atlas. It is noteworthy to observe that the crust does not thicken under the Kabylies that would indicate that their root is not enough to isostatically support the topography.