The eruption that began on 04/09/2021 at 7 p.m. (appearance of the tremor) at Piton de La Fournaise continues. The intensity of the volcanic tremor (indicator of the intensity of the eruption), after a relatively stable phase on the day of 04/10/2021, has been declining gradually since 9 a.m. local time on April 11.
Following an overview of the eruptive site carried out this morning with the assistance of the SAG and the PGHM, the eruptive fissure could be located with precision, 700 m southwest of the Château Fort crater. During the flyby, around 8:40 a.m. local time, activity focused on two main eruptive vents in which several regimes of lava fountains were observed. The upstream part of the crack is no longer active. The lava fountains did not exceed thirty meters in height
The flow had traveled about a mile to the east and the flow front, consisting of aa lava, was spreading very slowly. It was this morning at 8:40 am around 1800 m altitude.
The eruption continues on April 12. The intensity of the volcanic tremor (indicator of the intensity of the eruption), despite some fluctuations, remains relatively stable
Over the last 24 hours, 93 superficial volcano-tectonic earthquakes (between sea level and surface) have been recorded under the summit craters.
Piton de La Fournaise - Evolution of the RSAM (indicator of the volcanic tremor and the intensity of the eruption) since 04/09/2021 on the FOR seismological station located at the Château Fort crater (© OVPF-IPGP).
InSAR satellite data shows that the deformations, in the order of decimeter, linked to the injection of magma towards the eruptive site have remained confined inside the Enclos Fouqué caldera. These data are in good agreement with the data recorded on the permanent GPS stations of the OVPF-IPGP which recorded up to 40 cm of deformation in the area of the Château Fort crater.
Piton de La Fournaise - The above interferogram shows the deformation of the surface associated with the eruption of April 9, 2021. Each complete color cycle (from red to blue) of the interferogram corresponds to 27.8 mm of displacement of the surface towards (positive) or against (negative) of the Sentinel-1 satellite (the direction of which is represented by the arrow “LOS” at the top right of the figure). (© LMV-OPGC-OVPF-IPGP)
Satellite data also made it possible to trace the precise outline of the lava flow. On April 11, around 7 p.m. local time, the flow had traveled since the start of the eruption about 3.2 km and the flow front was located at the level of the Grandes Pentes broken (around 1690 m above sea level), like this was visible on the OVPF-IPGP webcam located in Piton des Cascades
The NOVAC data from the OVPF-IPGP stations since April 9 indicates a moderate SO2 emission rate, between 2 and 4 kilotons / day at most. With regard to the composition of emissions at Piton de la Fournaise, this is equivalent to a surface flow of the order of 10-25 m³ / s.
Piton de La Fournaise - 11.04.2021 / 6:20 pm UT - the flow front at the level of the large slopes - Camera Cascades OVPF
Scientific update on the Soufrière de St. Vincent eruption of 11.04.21 / 9h - UWI-SRC
During the last twelve hours, episodes of tremor lasting up to 20 minutes have continued to be recorded.
The intervals between the tremor episodes were 1.5 to 3 hours.
Based on visual observations and satellite imagery, the intervals are associated with periods of explosive activity or enhanced ventilation.
Thunder and lightning were felt during these times.
Heavy ash falls were observed at Belmont Observatory throughout the night.
Ash also reportedly occurred in most parts of the island overnight and in neighboring islands: the Grenadines, Barbados and Saint Lucia.
Soufrière de St. Vincent - Copernicus images from 09 and 10.04.2021 (top) and from 10.04.2021 / 16:42 UTC - ash on SVG and Barbados (bottom) - NASA image NOAA VIIRS NPP
Soufrière de St. Vincent - ash falls at the belmont observatory & weight of ashes on the tree branches, with threat of rupture - photos R.Robertson 04.11.2021 - one click to enlarge
Soufrière de St. Vincent - roofs collapsed under the weight of ash in the north of the island - photo 04.11.2021 / Flash Hurricanes Météo Antilles
Explosions and accompanying ash fall of a similar or greater magnitude will likely continue to occur over the next few days.
Sources: UWI-SRC & NEMO SVG
About 3,200 people took refuge in 78 government-run shelters, and four empty cruise ships stood ready to take other evacuees to neighboring islands, with a group of more than 130 already taken to St. Lucia. Those staying in the shelters were tested for COVID-19, with anyone who tested positive being taken to an isolation center.
Neighboring countries, including Antigua and Grenada, have also offered to host the evacuees.
The ashes forced the cancellation of several flights and poor visibility limited evacuations in some areas. Officials have warned that Saint Lucia to the north and Grenada to the south could have slight ashfall, though most of it were to head northeast into the Atlantic Ocean.
Source: AP / 10.04.2021
Reykjanes Peninsula - the 4 eruptive sites active on 04.11.2021 / 04:37 - mbls webcam - note the presence of a fox which remains at a distance from the lava - a click to enlarge
In the Reykjanes peninsula, the eruption at the start of the 4 active sites does not weaken.
The gas pollution caused by the eruption will cover the colonies of Suðurnes this April 11, according to the gas pollution forecasts of the IMO.
"It is a southeasterly windy night so the gaseous pollution is blowing towards Reykjanesbær, Garður and Sandgerði and over the north-western part of the Reykjanes peninsula today. Tonight the pollution is expected to go straight to it. west, which is a fairly uninhabited area. Tomorrow it should be laid again on the northwestern part of the Reykjanes peninsula, "says a meteorologist on duty at the Icelandic meteorological office.
"It is particularly important for people with a sensitive respiratory system to avoid straining during pollution."
Reykjanes Peninsula- the Meradalur site surrounded too closely by visitors - note the "reservoir" formed near the cone which can suddenly release large amounts of lava - photo SkyAlert
Caution is strongly recommended to people who go near the lava, and who break into any common sense, between two arms of flow, being able to let out at any time a packet of molten lava, or collapse .
Sources: IMO, RUV, mbls.