Report on Piton de la Fournaise (France) — 14 March-20 March 2001
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 March-20 March 2001
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2001. Report on Piton de la Fournaise (France). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 14 March-20 March 2001. Smithsonian Institution and US Geological Survey.
Piton de la Fournaise
21.244°S, 55.708°E; summit elev. 2632 m
All times are local (unless otherwise noted)
The OVPDLF reported that instrumental measurements suggest that Piton de la Fournaise may be entering a phase of heightened activity. Periods of increased seismic activity were recorded in late January with up to 13 earthquakes per day, in late February to early March with up to 126 earthquakes per day, and from 10 March until at least 15 March with up to 20 earthquakes per day. Inflation was detected at the volcano's summit from mid-January to early February, and from the end of February to early March. Since mid-January a continuous opening of fissures was recorded at the N and S bases of the volcano, indicating inflation of the summit area. Similar variations in activity were observed before eruptions on the E and S flanks of the volcano in 1999 and 2000.
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.