Report on Piton de la Fournaise (France) — 16 August-22 August 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
16 August-22 August 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Piton de la Fournaise (France). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 16 August-22 August 2017. 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)
Mainly based on seismicity, OVPF reported that the eruption at Piton de la Fournaise that began on 14 July continued during 16-22 August; weather clouds prevented visual and satellite observations most of the week. Volcanic tremor rapidly increased in the early evening on 15 August, concurrent with the presence of ephemeral lava fountains, at the cone and another area, visible in webcam images. The signal fluctuated at high levels until the evening of 19 August, when it began to stabilize at low levels. Satellite data from 19 August indicated a decreased lava-flow rate.
Geological Summary. 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.