OVPF reported that the eruption that began on 2 July at Piton de la Fournaise was ongoing during 12-19 July. Though there were multiple active fissures at the start of the eruption, since 3 July only the SE flank fissure was active, located on the upper part of Grandes Pentes at approximately 1,720 m a.s.l. Volcano-tectonic earthquake events (VTs) fluctuated throughout the week but remained low relative to the onset of the eruption. Lava ejections continued to build a cone over the active vent throughout the week, and on 12 July the top of the cone became partially closed. The flow front did not extend any further to the E and remained stalled 1.8 km from the road. Active flows traveled through lava tubes above 1,500 m elevation and continued to widen (increasing about 180 m since 7 July) and thicken. Although clouds often prevented measurements, satellite analysis showed that lava flow rates fluctuated between less than 1 and 13.5 cubic m/s. The total volume of lava effused since the beginning of the eruption was an estimated 6 +/- 3 million cubic meters. There was slight deflation at the summit during 13-16 July, followed by slight inflation during 17-19 July.

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)