Report on Piton de la Fournaise (France) — 13 February-19 February 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 13 February-19 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, 13 February-19 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 a seismic crisis began at Piton de la Fournaise at 1521 on 16 February accompanied by rapid deformation. The number of earthquakes sharply decreased at 1618 and deformation stopped at 1630. A second seismic crisis began at 0916 on 18 February, again accompanied by rapid deformation. Tremor commenced at 0948, coincident with at least eruptive fissures opening on the E flank of Dolomieu crater. Weather conditions prevented good views of the eruption site. Lava fountains rose less than 30 m above the vents, and after about an hour the longest lava flow reached 1,900 m elevation. Lava effusion ceased at 2200 on 18 February. A seismic crisis began at 1500 on 19 February, and tremor began to be recorded at 1700. Gas emissions were recorded by webcams for about an hour. During an overflight on 20 February the OVPF team observed a new eruption site located at 1,800 m elevation at the foot of Piton Madoré. One fissure opened and at 0620 only one lava fountain was active. The front of a lava flow reached 1,300 m elevation.
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.