STRESS-DISTRIBUTION OVER THE MOZAMBIQUE RIDGE

The Mozambique Ridge is an aseismic oceanic plateau in the southwester n Indian Ocean. During the separation of Antarctica and South Africa i n the Early Cretaceous, the Mozambique Ridge was segmented by fracture zones which were assumed to become inactive during the Cenomanian, wh en Africa and Antarctica were finally separated. However, the existenc e of active normal faulting in the central part of the Mozambique Ridg e was demonstrated by single and multichannel seismic surveys. Numeric al modelling of the stress distribution caused by the crustal structur e of the Mozambique Ridge and the adjacent oceanic basins suggests the possible existence of a zone with average horizontal tension up to 70 MPa along the central part of this passive ridge, which may cause the modern fault activity. These stresses also cause an additional dynami c anomaly which can explain small variations of the geoid anomaly over the ridge.