OVPF reported that activity continued during 20-26 February from the fissure that opened on 19 February; the site is at 1,800 m elevation at the foot of Piton Madoré, E of Piton de la Fournaise’s Dolomieu Crater. On 21 February scientists mapped the slowly eastward-advancing flows (and also those that had erupted on 18 February). They noted that the cone at the vent was growing, and hosted a lava lake that ejected spatter from bursting gas bubbles. A channelized lava flow traveled 1 km E and descended 200 m elevation before splitting into two flows near Guyanin Crater. The more northern of the two flows was 50 m wide and had progressed as far as 1,320 m elevation. The second more southerly flow was 200 m wide and itself split into two flows about 300 m SE of Guyanin Crater; one branch went to about 1,350 m elevation and the other to 1,300 m. Overall the longest part of the lava flow had traveled 1.9 km from the vent. During 22-26 February the lava emission rate was variable up to 16 cubic meters per second (based on satellite data), though webcam images from 24 February indicated that the flow had not significantly advanced.

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)