Report on Piton de la Fournaise (France) — 28 May-3 June 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 28 May-3 June 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Piton de la Fournaise (France). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 28 May-3 June 2003. 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)
An eruption began at Piton de la Fournaise on 30 May around 1155 at Dolomieu crater in the area where the December 2002 collapse occurred. The eruption was preceded by a slight increase in seismicity on 28 May, which included a small seismic swarm. Another swarm took place on the morning of 30 May, and at 1155 tremor began beneath Dolomieu crater. Then the eruption began, producing a lava flow that reached a length of ~400 m and a width of 250 m in the western part of Dolomieu crater. In addition, lava fountaining was observed until ~1400, after which most surface activity ceased. By 1 June at 1000 no tremor was recorded, marking the end of the eruption.
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.