Mass-Transport Deposits on the Algerian Margin (Algiers Area): Morphology, Lithology and Sedimentary Processes

On 21st May 2003, a damaging earthquake of Mw: 6.9 struck the region of Boumerdes 40km east of Algiers in northern Algeria. The seismic shocks had devastating effects in the offshore area between the cities of Algiers and Dellys, where numerous cable breaks were observed. The submarine area encompassing the 2003 Boumerdes epicenter (central Algerian margin) was recently investigated using geophysical and sampling tools. It has been observed that small-size slides and mass-transport deposits occur across this area. Thus, a detailed analysis was performed on 25 submarine slides identified in water depths from 500 to 2,700m, by measuring different morphological parameters (i.e. surface, head-scarp height, slope in the source area and in adjacent areas). Various deposits consisting of matrix supported mud-clast, distorted stratified sediments and sand-turbidite beds were observed in gravity cores near and within the most significant-size slide. Based on this work and previous studies it can be presumed that the recurrent seismic activity can be considered as the main triggering factor for failure in the central Algerian margin.