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Report on Piton de la Fournaise (France) — February 1986

Scientific Event Alert Network Bulletin, vol. 11, no. 2 (February 1986)
Managing Editor: Lindsay McClelland.

Piton de la Fournaise (France) Eruptive episode ends

Please cite this report as:

Global Volcanism Program, 1986. Report on Piton de la Fournaise (France). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 11:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198602-233020.

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Piton de la Fournaise

France

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

All times are local (unless otherwise noted)


The eruptive episode . . . ended on 7 February. Aphyric basalt lavas covered 95% of the floor of Dolomieu Crater. The volume of lava emitted is estimated to be 7 x 106 m3. Deflation was observed on the summit levelling stations in mid-February. A short seismic crisis occurred on 11-12 February; events were located E of the summit at 3 km depth. Since then seismic activity has returned to a very low level. Volcanic activity in 1985 is summarized in table 3. The total amount of lava emitted [in 1985] is estimated to be 33 x 106 m3.

Table 3. Summary of 1985 eruptive episodes at Piton de la Fournaise.

Start Date Duration Lava volume (106 m3)
14 Jun 24 hours 1
05 Aug 4 weeks 7
06 Sep 6 weeks 17
02 Dec 28 hours <=1
29 Dec 6 weeks 7

Geologic Background. The massive Piton de la Fournaise basaltic shield volcano on the French island of RĂ©union 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.

Information Contacts: H. DeLorme and J-F. DeLarue, OVPDLF; P. Bachelery, Univ de la RĂ©union.