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Report on Piton de la Fournaise (France) — 14 October-20 October 2015

Piton de la Fournaise

Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
14 October-20 October 2015
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2015. Report on Piton de la Fournaise (France). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 14 October-20 October 2015. Smithsonian Institution and US Geological Survey.

Weekly Report (14 October-20 October 2015)

Piton de la Fournaise


21.244°S, 55.708°E; summit elev. 2632 m

All times are local (unless otherwise noted)

OVPDLF reported that on 12 October there was a strong increase in tremor intensity at Piton de la Fournaise, with values reaching or exceeding those detected during the first few hours of the beginning of the eruption (24 August). A strong increase in sulfur dioxide emissions was also detected by a ground-based DOAS (Differential Optical Absorption Spectrometer); values on 2 October were 205 tonnes per day (t/d) and values on 12 October were 1,990 t/d. A satellite-based sensor recorded 1,138 t/d during 13-14 October which was twice the amount measured on 24 August. The satellite-based lava-flow rate on 14 October was 12 m³/s (±4 m³/s), consistent with model data. Strain measurements showed deflation. Several small ephemeral vents across the lava field produced lava flows, and in many instances hornitos were present at these vents. A hornito SW of the cone ejected spatter during 13-14 October. Activity continued to increase on 17 October. The cone continued to grow; the base was 100 m in diameter and it was about 40 m high. Parts of the cone rim continued to collapse, and a notch in the rim allowed for periodic lava-lake overflows.

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.

Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)