Report on Piton de la Fournaise (France) — November 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 11 (November 1987)
Managing Editor: Lindsay McClelland.
Piton de la Fournaise (France) New fissure eruptions
Please cite this report as:
Global Volcanism Program, 1987. Report on Piton de la Fournaise (France) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 12:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198711-233020
Piton de la Fournaise
21.244°S, 55.708°E; summit elev. 2632 m
All times are local (unless otherwise noted)
An increase in seismicity began 3 November, associated with weak inflation NE of Dolomieu summit crater. An eruptive phase followed on 6 November at 2111, on the N flank of the cone. After a discernable decrease in tremor and continuing seismic activity, a second eruptive phase was registered at 2147. Activity lasted until about 2330. During these two phases, a series of three fractures had opened ~1 km N of Dolomieu. The main aa flow had stopped advancing by the time a new fissure opened at 0040 on 7 November, 1 km NE of the earlier fissures. About 1.6 x 106 m3 of aphyric basalt had been extruded by the end of all activity at 0600 on 8 November.
On 29 November an earthquake swarm of ~20 events was recorded. An eruption began the next day when a new fissure opened at 0805 in Enclos Caldera S of the central cone. A second fissure opened at 0932. On 1 December, there was moderate activity during a single event and weak tremor.
Geological Summary. Piton de la Fournaise is a massive basaltic shield volcano on the French island of Réunion in the western Indian Ocean. 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 scarps formed at about 250,000, 65,000, and less than 5,000 years ago by progressive eastward slumping, leaving caldera-sized embayments open to the E and SE. Numerous pyroclastic cones are present on the floor of the scarps and their outer flanks. Most recorded eruptions have originated from the summit and flanks of Dolomieu, a 400-m-high lava shield that has grown within the youngest scarp, which is about 9 km wide and about 13 km from the western wall to the ocean on the E 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 outside the scarps.
Information Contacts: P. Bachélery, Univ de la Réunion; OVPDLF (translated from a report inLAVE Bulletin no. 11).