Piton de la Fournaise, 2,630 m high, is a basaltic volcano located in the Indian Ocean. The Self-Potential map of Enclos Fouque was determined in 1992 and 1993 with about 70 km of profiles. The cone is the seat of a huge positive anomaly whose amplitude is more than 1,850 mV. During the last 10 years an SP anomaly has developed on a N 130-degrees direction indicating a new fracture zone. A large positive horseshoe-shaped anomaly is superimposed on the huge anomaly associated with the cone. The shape and the amplitude of the SP anomalies suggest that the source, the magmatic complex, is at least at 2 km depth beneath the summit. Inside the cone hydrothermal ascendant circulations are trapped by the fractures due to dyke migration and are progressively channelled along radial and concentric faults to the summit. The horseshoe-shaped positive anomaly is the electric signature of reheated fluid circulations escaping from Enclos Fouque to the Indian Ocean through the main fracture zone. The profile around Bory and Dolomieu craters has been made three times embracing one summital eruption. A local 1,250 mV, 150 m wide, anomaly has been observed in the axis of dry fissures and disappeared 2 months later.
|Translated title of the contribution||Self-Potential anomalies and convective systems on la Fournaise Volcano (Reunion Island, France)|
|Pages (from-to)||1325 - 1331|
|Journal||Comptes Rendus de l'Académie des Sciences|
|Publication status||Published - 1994|