Report on Piton de la Fournaise (France) — 18 June-24 June 2014
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
18 June-24 June 2014
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2014. Report on Piton de la Fournaise (France). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 June-24 June 2014. 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)
OVPDLF reported that an eruption began at Piton de la Fournaise at 0120 on 21 June 2014 following a period of elevated seismicity. This new activity marks the end of more than three years of quiescence.
During 7-20 June volcano-tectonic and rockfall-type earthquakes were recorded, with the largest number occurring on 17 June. The locations of these earthquakes were relatively consistent between 500 and 1,200 m a.s.l. within Dolomieu crater. There were neither significant gas emissions nor indicators of pre-eruptive deformation. On 19 June, a field campaign by the Observatory team confirmed the activity detected by the permanent monitoring network (geodetic, thermal, and gas).
At 0006 on 21 June the seismic crises escalated and continued for 74 minutes. Localized deformation began at 0020 and continued for ~3 hours. Tremor began at 0120 and incandescence was observed by the remote cameras at 0135. The eruption was entirely contained within the Enclos Fouqué area on the ESE side of the central cone. Aerial observations by helicopter revealed an active lava fountain from a fissure that was within view of the Piton Bert webcamera. The fountaining built a spatter rampart and two lava flows extended ~1.5 km from the fissure. One lava flow extended 250 m after passing the Langlois crater (~2 km SE of Dolomieu crater); the second lava flow passed that crater on the E and S edge and extended an additional 500 m.
Public access to the volcano was restricted on 21 June and Alert Level 1 (“probable or imminent eruption”) was announced.
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.