OVPF reported that the eruption at Piton de la Fournaise continued during 29 December 2021 to 4 January 2022. Weather clouds often obscured views of the vent, though visual observations were made daily. Low lava fountaining, with material rarely rising just above the crater rim, was visible on 29 December. A small mound with a vent that had grown at the base of the main cone was producing gas emissions, and lava advanced through a tube. Lava fountaining was slightly more intense during 30 December 2021 to 3 January 2022, with lava more frequently rising above the crater rim. Several breakouts of lava from the tube were noted downstream of the vent. The lava effusion rate was an estimated 2.3-9 meters per second, with peak rates of 21 meters per second, based on satellite data. Activity at the main cone decreased during 3-4 January. Lava flows within the first 100 m from the cone were an estimated 15 m thick. The flow field continued to widen but had not significantly lengthened.

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)