Report on Piton de la Fournaise (France) — 4 December-10 December 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 December-10 December 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Piton de la Fournaise (France). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 4 December-10 December 2002. 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)
Lava emissions from Piton de la Fournaise that had begun on 16 November ended on 3 December. Permanent tremor decreased significantly that day, although seismic events beneath the summit continued at a rate of one a minute. Sesimicity continued to decline over the next 2 days. Poor weather conditions prevented helicopter observations during 3-5 December. Inspection on 6 December revealed some areas of collapse between Bory and Dolomieu craters and white fumes that were released from a new cone named Guanyin. There was no evidence of surface activity coincident with larger seismic events that occurred while scientists from OVPDLF were on the edge of Dolomieu crater.
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.