Title: Potential fields study in the NW of Algeria: Evidences of active faults and underground structure

Abstract

The NW of Algeria is known as one of the seismic active zone in Algeria and the West Mediterranean region. It constitutes a key area to study neotectonics structures and their geodynamical context. Until now, there is a little information about existence of deep active faults, which generate this strong activity. Potential fields data (aeromagnetic and gravity) are an important resource of information on crustal structure. The aim of this work is giving a reliable geometry of the major faults relative to the kinematics of this region. The results obtained from various filtered maps (shaded relief, derivatives, upward continuation) of the magnetic and gravity data were used to generate a structural map of the studied area. Whilst the continuous wavelet and ridgelet transforms can help in automatic detection of elongated structures in 3-D both onshore and offshore, to estimate their strike direction, shape and depth. The short wavelength potential fields anomalies are related to volcanic rocks on the coast and to the basement in sedimentary basins. The long wavelength anomalies are associated mainly with deep E-W structures, limiting the basins. In the North, similar structures have been identified in the Mediterranean Sea. This work yields to 2-D and 3-D image of the region and confirms the existence of several faults, localized or inferred, from former geological studies.