Report on Piton de la Fournaise (France) — 23 November-29 November 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 23 November-29 November 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Piton de la Fournaise (France). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 23 November-29 November 2005. 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)
OVPDLF reported that immediately after the end of the last eruption at the Dolomieu crater of Piton de la Fournaise that began on 5 October 2005, the permanent Global Positioning System (GPS) network and extensometer network at the volcano continued to show strong surface deformation, which was a precursor for a new eruptive event. On 29 November at 0559 a seismic crisis began at the volcano and at 0625 tremor indicated the beginning of an eruption. A vent opened in the western part of Dolomieu crater and another vent opened on the volcano's N flank. Very little projected volcanic material was visible. A rapid and large lava flow traveled down the N flank in the direction of Piton Kapor. Inclement weather prohibited further observations. The Toulouse VAAC reported that ash from the eruption was not visible on satellite imagery.
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.