La Palma - the eruptive site in a cloud gap - image Sentinel-2 bands 12,11,4 from 20.09.2021 - one click to enlarge
The eruption is still in progress in La Palma, the lava is not very fluid and the flows follow the channels, they do not jump obstacles, according to Stavros Meletlidis, volcanologist at the National Geographic Institute / Espejo Publico .
The rash will completely change the orography (*). The land will become unusable and uninhabitable. The lava flows which descend the western slopes of La Palma towards the coast, are of an average height of 6 meters, and advance at 700 meters per hour. They will bury land, electrical and telephone communications and create acid rain when, in the next few hours, they reach the sea.
(*) Orography is the part of physical geography that is devoted to the description of mountains.
La Palma - 09.20.2021 advanced lava flow - destruction of homes - Forecast risk map - logarithmic probability of lava invasion with heights of 6 m to less than 5 meters - the eruptive fracture is symbolized by a line blue. Doc. IGNes and press - one click to enlarge
Simulations carried out by the National Geographic Institute (IGN) estimate that the lava is directed towards the cores of La Bombilla and Puerto Naos, on the coast.
Throughout the early hours of Monday, the volcano continued to expel large amounts of lava and gases and pyroclasts. Evacuations of the affected and at-risk population have already been completed, with the exception of a few scattered houses, and all places where lava may occur have been evacuated.
According to the latest information, the new volcano has two cracks, about 200 meters apart, and eight mouths through which the lava emerges, which would have affected more than 160 houses on its way to the coast through the El Paso ravine.
The lava has already reached the municipality of Los LLanos de Aridane after crossing the LP2 road.
Classes are suspended in El Paso, Los Llanos de Aridane and Tazacorte due to the eruption of the volcano.
La Palma - SO₂ emissions pass over La Gomera and reach the African coast - image Sentinel-5P Tropomi (via S. Carn) from 20.09.2021 / 14:12
Sentinel5P / TROPOMI data from September 20 shows SO2 emissions from the eruption passing over La Gomera and reaching the West African coast. The SO2 plume data is very high (> 700 DU) at the eruption site. The total mass of SO₂ is approximately 30 to 65 kilotons depending on the assumed altitude of the plume.
On the other hand, the deformation of the ground, which had reached 15 centimeters before the eruption of the volcano, increased to 19 centimeters: there is still a magmatic input in the area, and new cracks may appear in the following hours and days.
At around 9 p.m. local time, a new crack opened, one km away. west of other vents; an earthquake of Ml 3.8 followed at 9:32 am loc.
An in-depth study has been carried out for years to define the state of volcanic unrest in La Palma, by José Fernandez & al., published in Nature / Scientific reports (source references) in January 2021.
This was accomplished thanks to the use of satellite radar observations and an original advanced interpretation technique. This study shows the detection of the onset of volcanic unrest on the island of La Palma, most likely decades before a potential eruption.
La Palma - Conceptual model of the evolution of unrest. Two main surfaces obtained in the 3D gravimetric crustal model (green and gray surfaces), the sources of positive pressure modeled for the periods 2006-2010 and 2017-2020, the sources modeled for landslides and dips in 2019-2020 and the location of events seismic. The proposed path followed by the seismic depth magma (yellow path) before, and probably after, the seismic swarms in 2017 and 2018 that could have opened new fractures. - Source: IGEO (CSIC-UCM)
The geodesic techniques used here make it possible to follow the migration of fluids induced by the injection of magma at depth and to identify the existence of sources of dislocation, under the Cumbre Vieja volcano. Therefore, they should continue to be monitored using these and other techniques. The results have implications for monitoring steep-sided volcanoes on oceanic islands.
Sentinel-5P / Tropomi for SO2 emissions; Sentinel-1 for deformation; Sentinel-2 for thermal anomalies / the Sentinel system has been activated by the European Commission with Copernicus - Doc. Mounts project / Twitter compte @MountsSystem. - one click to enlarge
- Canary Islands media: RTVC - Tiempo de Canarias
- Mounts Project
- Sentinel-5P / Tropomi for SO2 emissions; Sentinel-1 for deformation; Sentinel-2 for thermal anomalies / the Sentinel system has been activated by the European Commission with Copernicus
- Detection of volcanic unrest onset in La Palma, Canary Islands, evolution and implications - by José Fernández, Joaquín Escayo, Zhongbo Hu, AntonioG. Camacho, SergeyV. Samsonov, Juan F. Prieto, Kristy F. Tiampo, Mimmo Palano, Jordi J. Mallorquí & EumenioAncochea. / Nature Scientific reports - link
In Fagradalsfjall, a new measurement of the lava volume took place on September 17. Aerial photographs were also taken by the Institute of Natural History from the Fisfélag plane. Terrestrial models were made based on these measurements and they were compared to older data.
The measurements show that the average lava flow over this eight-day period was 11.8 m³ / s. The same lava flow was the longest in May and June, but longer than in August. The eruption was down on 9 but resumed on 11 September. We can therefore see that the average flow was 16 m³ / s from September 11th to 17th.
The lava is now 151 million cubic meters and the area 4.8 square kilometers.
After the eruption resumed, lava flowed into Geldingadalur and reached Nátthaga. Lava flowed north for some time and filled a gap that was between the northern craters active in April and the high plain of Fagradalsfjall.
It should be noted that the measurements show the volume and its changes. The density of the lava can vary and it has been pointed out that next to the craters there is a cavity further or less far. No attempt is made here to estimate this effect, to find an equivalent volume of dense rock or lava mass. A common estimate is that the volume of dense rock is around 80% of the total volume and it is likely that the same applies to lava at Meradalir, Geldingadalur and Nátthaga, but the cavity is closer to the crater.
Fagradalsfjall - coumée in the valley of Natthaga on 09.19.2021 at 6:20 a.m. and 9:50 a.m. Webcam Almannavarnir Borgarfjall
Fagradalsfjall - thermal anomalies at 19.09.2021 (flow in Geldingadalur and Natthaga) the lava field can be seen to the right of the flows (in black) - - image Sentinel-2 bands 12,11,4 - one click to enlarge
Fagradalsfjall - extension of the lava field, update 20.09.2021 - Doc. GeoVis Lab Iceland / Un. Iceland
Etna had to come forward and get some media coverage for him.
The mean amplitude of the volcanic tremor, after a first gradual increase started with large oscillations a few hours earlier, showed a sudden increase from 02:20 UTC today and around 02:40 UTC it reached the range of high values. The volcanic tremor source centroid is located in the south-eastern crater area at an altitude of about 2900 m above sea level.
From around 6:15 a.m. UTC, images from video surveillance cameras show an ash emission from the southeast crater.
At 6:55 UTC we observe the resumption of Strombolian activity at the level of the Southeast crater. The eruptive cloud produced by the current activity reaches a height of about 4500 m and, depending on the model
expected, it disperses towards the ENE.
The increase in the mean amplitude of the volcanic tremor continues with a further increasing trend. The center of gravity of volcanic tremor sources is located in the south-eastern crater area at an altitude of about 2900-3000 m above sea level.
Source: INGV OE