Report on Piton de la Fournaise (France) — March 1981
Scientific Event Alert Network Bulletin, vol. 6, no. 3 (March 1981)
Managing Editor: Lindsay McClelland.
Piton de la Fournaise (France) Lava from new vents
Please cite this report as:
Global Volcanism Program, 1981. Report on Piton de la Fournaise (France). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 6:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198103-233020.
Piton de la Fournaise
21.244°S, 55.708°E; summit elev. 2632 m
All times are local (unless otherwise noted)
The activity SW of the summit that began 26 February continued until 25-26 March. A new eruption on 1 April was preceded by a swarm of local earthquakes, starting at 1923. The seismographs at Réunion's volcano observatory registered 72 discrete events in the next few hours, before the onset of harmonic tremor and the start of an eruption at 2141. Observatory personnel reported that lava extruded from a vent in the north-central area of the caldera, 3 km ENE of the summit, flowed toward the N caldera wall, reaching it during the night. By the early afternoon of 2 April, the flow front was 1 km W of the coast highway [but see 6:4], but the lava's rate of advance had slowed considerably.
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: J. LeMouel and J-L. Cheminée, IPG, Paris.