Report on Piton de la Fournaise (France) — November 1975
Natural Science Event Bulletin, vol. 1, no. 2 (November 1975)
Managing Editor: David Squires.
Piton de la Fournaise (France) Eruption begins on 4 November after 31-month repose
Please cite this report as:
Global Volcanism Program, 1975. Report on Piton de la Fournaise (France) (Squires, D., ed.). Natural Science Event Bulletin, 1:2. Smithsonian Institution.
Piton de la Fournaise
21.244°S, 55.708°E; summit elev. 2632 m
All times are local (unless otherwise noted)
After a 31-month repose, the volcano began erupting on 4 November at the S end of Brulant Crater, 2,300 m above sea level. A 400-m-long fissure opened, trending NW-SE, and five cinder cones formed along its length. On 5 November one cone, 50 m high, was still active at the SE end of the fissure. A 10-m-wide lava lake formed. During the following 10 days 180,000 m3 of aphyric basalt aa was emitted. By 14 November the eruption was decreasing, the crater was degassing, and the lava flows were reported as small.
Further Reference. Krafft, M., and Gerente, A., 1977, L'Activite du Piton de la Fournaise entre Novembre 1975 et Avril 1976 (Ile de la Réunion, Ocean Indien): C.R. Acad. Sci. Paris, serie D, v. 284, p. 2091-2094.
Geologic Background. The massive Piton de la Fournaise basaltic shield volcano on the French island of Réunion in the western Indian Ocean is one of the world's most active volcanoes. Much of its more than 530,000-year history overlapped with eruptions of the deeply dissected Piton des Neiges shield volcano to the NW. Three calderas formed at about 250,000, 65,000, and less than 5000 years ago by progressive eastward slumping of the volcano. Numerous pyroclastic cones dot the floor of the calderas and their outer flanks. Most historical eruptions have originated from the summit and flanks of Dolomieu, a 400-m-high lava shield that has grown within the youngest caldera, which is 8 km wide and breached to below sea level on the eastern side. More than 150 eruptions, most of which have produced fluid basaltic lava flows, have occurred since the 17th century. Only six eruptions, in 1708, 1774, 1776, 1800, 1977, and 1986, have originated from fissures on the outer flanks of the caldera. The Piton de la Fournaise Volcano Observatory, one of several operated by the Institut de Physique du Globe de Paris, monitors this very active volcano.
Information Contacts: L. Montaggioni, Univ. de la Réunion.