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. Piton de la Fournaise is a massive basaltic shield volcano on the French island of Réunion 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.