Report on Piton de la Fournaise (France) — 20 February-26 February 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 February-26 February 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on Piton de la Fournaise (France). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 20 February-26 February 2019. 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 activity continued during 20-26 February from the fissure that opened on 19 February; the site is at 1,800 m elevation at the foot of Piton Madoré, E of Piton de la Fournaise’s Dolomieu Crater. On 21 February scientists mapped the slowly eastward-advancing flows (and also those that had erupted on 18 February). They noted that the cone at the vent was growing, and hosted a lava lake that ejected spatter from bursting gas bubbles. A channelized lava flow traveled 1 km E and descended 200 m elevation before splitting into two flows near Guyanin Crater. The more northern of the two flows was 50 m wide and had progressed as far as 1,320 m elevation. The second more southerly flow was 200 m wide and itself split into two flows about 300 m SE of Guyanin Crater; one branch went to about 1,350 m elevation and the other to 1,300 m. Overall the longest part of the lava flow had traveled 1.9 km from the vent. During 22-26 February the lava emission rate was variable up to 16 cubic meters per second (based on satellite data), though webcam images from 24 February indicated that the flow had not significantly advanced.
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.