STRUCTURAL MAP OF THE CHELIF BASIN (ALGERIA) AFTER GRAVITY-DATA

A new gravity survey of the region surrounding the Chelif earthquake z one (Algeria) contributes to a better understanding of its deep struct ures. Two main domains have been recognized: one in the South is chara cterized by a shallow basement; the other in the North showing the sam e basement buried beneath the deep Chelif basin. Three main faults tre nding more or less in an E-VV direction separate or affect the two zon es. All these structures are cut by transverse faults which acted as d extral or sinistral shear zones. One of these offsets the Chelif basin . The southern zone, characterized by a shallow basement, acted probab ly like an indenter.