OVPF reported that intermittent inflation at Piton de la Fournaise had been detected since the end of the last eruption on 28 August 2017. Seismicity began increasing the last two weeks in February. Seismicity fluctuated during March; peaks were recorded on 28 and 31 March, with volcano-tectonic earthquakes occurring less than 2 km below the summit area. An enrichment of carbon dioxide and sulfur dioxide in summit fumaroles was noted on 23 March.

A seismic crisis began at 0300 on 3 April, and along with deformation, indicted magma migration towards the surface. An eruption began at 1040 on the N flank, just below the rampart at the Nez Coupé de Sainte Rose area. During an overflight, scientist observed a 1-km-long fissure, divided in seven segments, with two active vents producing lava fountains. At 1600 many landslides were recorded by the seismic network in the active area. The eruption ended At 0400 on 4 April, though a few landslides were recorded through 1530.

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)