Report on Piton de la Fournaise (France) — November 1977
Natural Science Event Bulletin, vol. 2, no. 11 (November 1977)
Managing Editor: David Squires.
Piton de la Fournaise (France) Two fissures open in late October and emit lava flows
Please cite this report as:
Global Volcanism Program, 1977. Report on Piton de la Fournaise (France) (Squires, D., ed.). Natural Science Event Bulletin, 2:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.NSEB197711-233020.
Piton de la Fournaise
21.244°S, 55.708°E; summit elev. 2632 m
All times are local (unless otherwise noted)
Two fissures opened during the morning of 24 October on the E slope of Dolomieu Crater, within the caldera. The first fissure opened at 2,180 m altitude at 0830, and emitted an aa lava flow, which stopped the next day after traveling to 500 m altitude. The second fissure opened one hour after the first at 1,920 m altitude. Moderate explosive activity from this fissure built a single tephra cone until 26 October, when a second, immediately adjacent cone began to grow. Activity from the two cones remained fairly constant until lava fountaining began on 1 November. Fountains initially rose 200 m above the cones, but gradually declined until 10 November, when new lava covered 4 km2. Fountaining re-intensified 10-13 November, and was succeeded on 14 November by effusion of basaltic lava flows, with velocities reaching 60 km/hour. No casualties or damage occurred. The eruption ended at 1250 on 17 November.
Further Reference. Kieffer, G., and Vincent, P.M., 1978, The October-November 1977 Eruption of Piton de la Fournaise (Réunion Island): A terminal eruption without terminal crater: C.R. Acad. Sci. Paris, serie D, v. 286, p. 1767-1770.
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: M. Krafft, Cernay.