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) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 11:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198602-233020
Piton de la Fournaise
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.
|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|
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.
Information Contacts: H. DeLorme and J-F. DeLarue, OVPDLF; P. Bachelery, Univ de la Réunion.