Report on Piton de la Fournaise (France) — March 2004
Bulletin of the Global Volcanism Network, vol. 29, no. 3 (March 2004)
Managing Editor: Richard Wunderman.
Piton de la Fournaise (France) December 2003 lavas spread across 40% of Dolomieu crater floor
Please cite this report as:
Global Volcanism Program, 2004. Report on Piton de la Fournaise (France) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 29:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200403-233020.
Piton de la Fournaise
21.244°S, 55.708°E; summit elev. 2632 m
All times are local (unless otherwise noted)
BGVN 28:09 reported a seismic crisis and new SSW-flank fissure at Piton de la Fournaise on 30 September 2003. The Volcanological Observatory monitoring Piton de la Fournaise and the local press reported a further seismic crisis that developed on 7 December 2003 at 1429 beneath the summit. Following around an hour of seismicity, an eruption began on 7 December at 1535 in the Dolomieu crater, with lava fountaining to ten's of meters from two fractures on the SE crater floor. Two new fractures were also observed on the S crater rim that did not produce lava. The eruption decreased rapidly over the night of 7-8 December. By 8 December at about 1400 small incandescent lava flows and rock falls on the S crater wall were observed. By the night of 8 December the eruption ceased but strong degassing and fluctuating seismicity continued. New lava covered ~ 40% of the Dolomieu crater floor.
The eruption was preceded by a seismic swarm on 6 November that was followed by ~ 30 cm of steady uplift and 10-20 earthquakes recorded per day. As of 16 December, significant seismic activity continued, and hikers were permitted only limited access. Press reports indicated three quite active cones within the S rampart of the Dolomieu crater, surrounded by ejecta found more than 200 m N, noisy degassing, lava covering the bottom of the crater up to 5 m thick, and zigzag cracks crossing the crater's S exterior.
A further seismic event with significant surface deformation occurred over 7-9 January 2004.
[On 9 January eruption tremor started near Nez Coupé de Sainte Rose. A 300-m-long fissure, cutting the 1931 crater, produced a small ~2-km-long lava flow. The eruption stopped on 10 January around 1200.]
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: Thomas Staudacher, Observatoire Volcanologique du Piton de la Fournaise Institut de Physique du Globe de Paris, 97418 La Plaine des Cafres, La Réunion, France (URL: http://www.ipgp.fr/fr/ovpf/observatoire-volcanologique-piton-de-fournaise).