IS LA-FOURNAISE VOLCANO ERUPTIVE ACTIVITY CONTROLLED BY THE N120-DEGREES LITHOSPHERIC STRUCTURAL ANISOTROPY LOCATED BENEATH REUNION-ISLAND

Reunion Island is located directly above a lithospheric weakness zone trending N120 degrees. The volcanoes Pitons des Neiges and de la Fourn aise have been built along this tectonic axis. A large structure of in verse magnetization was found on this N12O degrees axis on the south-e astern flank of La Fournaise. A major fracture zone cuts the edifice o f La Fournaise from the south-east to the north-east. Most of the erup tions take place there. From 1950 to 1994, N120 degrees eruptions that occurred indicate that the end of each effusive cycle followed by sev eral years of inactivity. The evolution of the eruptive activity is co ntrolled by the regional stress field pattern and the local stress fie ld pattern induced by La Fournaise.