Report on Piton de la Fournaise (France) — 21 April-27 April 2021
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 21 April-27 April 2021
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2021. Report on Piton de la Fournaise (France) (Sennert, S, ed.). Weekly Volcanic Activity Report, 21 April-27 April 2021. 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)
OVPF reported that the eruption at Piton de la Fournaise continued during 21-27 April, though inclement weather conditions obscured visual observations most of the week. The average lava-flow rate was between 1.2 and 8.3 cubic meters per second during 16-23 April. The flow rates were estimated based on the gas-emission rates, though weather conditions may have affected the accuracy of the measurements. Lava continued to mostly flow in lava tubes; some flows thickened and parts of the flow field widened. The longest flow was 3.2 km long and the maximum width was 750 m, unchanged from the previous week. The flow field was mapped using a satellite image acquired on 24 April. The Alert Level remained at 2-2.
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.