Active Deformation in Northern Algeria from Continuous GPS Measurements and Recent Seismic Data

Abstract

Recent installation of GPS (Global Positioning System) network in northern Algeria (the REGAT REseau Geodesique de l’ATlas Project), combined with the seismic ADSN (Algerian Digital Seismic Network) data network, fills an important gap in our knowledge of the present-day Nubian–Eurasian plate boundary in the western Mediterranean where likely most of the oblique plate convergence concentrates. From ten years of continuous measurements, the first geodetic velocity field shows variations from west to east. In western Algeria, GPS velocities are uniform and collinear to the N50W NU–EU convergence trend while in the east they indicate that the deformation involves a broader region. These results are consistent with the recorded seismicity in northern Algeria and the geophysical investigations held in the Algerian offshore basin. GPS data show that the deformation in Algeria is accommodated in the west along an offshore reverse fault system that runs along the toe of the Algerian margin with a slip rate decreasing from west to east. To the east, the deformation is accommodated by an E–W-trending strike-slip fault and a shortening component distributed along a reverse fault system offshore and between the Saharan platform and the Aures range in southeastern Algeria.