OVPF reported that seismicity remained elevated at Piton de la Fournaise during 22-26 March. On 24 March there were 81 earthquakes recorded under the summit, accompanied by deformation and 31 collapses along the edges of the Dolomieu Crater. Inflation centered 1.5 and 2 km below the crater continued through the week. On 26 March up to 95 summit volcano-tectonic earthquakes were recorded; the daily number of earthquakes then decreased, with 55 on 27 March and 8 on 28 March.

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)