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Report on Piton de la Fournaise (France) — 23 November-29 November 2005


Piton de la Fournaise

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.

Weekly Report (23 November-29 November 2005)

Piton de la Fournaise

France

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.

Geological Summary. Piton de la Fournaise is a massive basaltic shield volcano on the French island of RĂ©union 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.

Sources: Toulouse Volcanic Ash Advisory Centre (VAAC), Observatoire Volcanologique du Piton de la Fournaise (OVPF)