La Palma volcano eruption update: high lava effusion rates, new lava arm at the sea, speculation about seismic activity

Mon, 11 Oct 2021, 10:33
10:33 AM | BY: T
Lava fountain, ash emission and lava flow today at noon (image: Live webcam)
Lava fountain, ash emission and lava flow today at noon (image: Live webcam)
Map of lava flows as of yesterday afternoon (image: x_y_es / twitter)
Map of lava flows as of yesterday afternoon (image: x_y_es / twitter)
Seismic spectrum at TBT station yesterday showing the tremor at 18 Hz (image: IGN)
Seismic spectrum at TBT station yesterday showing the tremor at 18 Hz (image: IGN)
Today, the eruption continues with steady lava fountaining from the lower vent and strong degassing and ash emission from the upper vents, but is much less noisy compared to yesterday, to the relief of people living in the area many of whom were terrorized by the extreme noise of the eruption in recent days.
The decrease of sound intensity is however not an indication of what state the eruption is in its deeper underground. It is mostly reflecting how gasses can escape and interact with the ambient air at the very surface. The decrease of eruption sound is likely due to an enlargement of the upper conduits after several collapses and other changes occurred at the vents, which now are in a more stable configuration to allow the passage of magma in a more unobstructed way. It probably has no significance as to the eruption's effusion rate, which continued to be very high. The past day's activity changed the morphology of the main cone quite a bit, by accumulation of falling material from the mountains, as well as overlapping lava flows.
The result is that the cone overall grew significantly and most lava now is going into the northern flow, which has been following the northern margin of the flow field, causing lots of additional damage in the past 48 hours. It reached the sea last night around 22.55 p.m., after passing north Montaña de Todoque (the cinder cone near Todoque, already half circled by lava flows on the southern side).
Lava threatens La Laguna
Forming a rather narrow front, its rate of advance was very fast, at about 500-700 m per hour. It is now hoped that its channel or tube system will remain stable to direct the lava straight into the ocean instead of widening the flow or branching off, which would put the town of La Laguna at risk.

Seismic activity shows worrying signs
According to a post of a geoscience page VolcanesyScienciaHoy on facebook based in Tenerife, the current seismic activity points towards that more magma is moving upwards, as indicated by 3 factors:
- several earthquakes appeared at depths less than 7-8-9 km;
- after the 4.2 quake two days ago, there have been episodes of spasmodic tremor with many earthquakes in a row that indicate movement of magma in depth;
- since yesterday, the appearance of strong volcanic tremor at around 18 Hz frequency thought to be caused by depressurization of fluids at great depth around 10 km;
If these interpretations hold, there should soon be noticeable ground uplift visible in the GPS stations (which, so far, is not the case). What will next happen, when this new magma pulse reaches the surface, is unknown. In the best scenario, the current conduits will continue to cope with it and the magma will erupt from the existing vents. In the worst scenario, magma could open new fissures in a different area, even after another potential pause of the eruption should it occur. In a scenario in between, new fissures might open near the existing vents, and new lava would erupt onto existing lava fields.
No one can predict the future, but for sure the evolution of the eruption will be a highly interesting one and the experience intense for everyone involved, in one way or another.

Previous news

Mon, 11 Oct 2021, 09:50
Earthquakes and depths under La Palma during the past 48 hours
The seismic activity under the island remains intense, but the quakes remain clustered in the same areas as before with no clear trend visible. ... Read all
Show more
Try our free app!
Volcanoes & Earthquakes - new app for Android
Android | iOS version

More on VolcanoDiscovery

Why is there advertising on this site?
Support us - Help us upgrade our services!
We truly love working to bring you the latest volcano and earthquake data from around the world. Maintaining our website and our free apps does require, however, considerable time and resources.
We need financing to increase hard- and software capacity as well as support our editor team. We're aiming to achieve uninterrupted service wherever an earthquake or volcano eruption unfolds, and your donations can make it happen! Every donation will be highly appreciated. If you find the information useful and would like to support our team in integrating further features, write great content, and in upgrading our soft- and hardware, please make a donation (PayPal or Online credit card payment).

Planned features:
  • Improved multilanguage support
  • Tsunami alerts
  • Faster responsiveness
Thanks to your past donations, these features have been added recently:
  • Earthquake archive from 1900 onwards
  • Detailed quake stats
  • Additional seismic data sources
Download and Upgrade the Volcanoes & Earthquakes app to get one of the fastest seismic and volcano alerts online:
Android | IOS
Thank you!
Copyrights: VolcanoDiscovery and other sources as noted.
Use of material: Most texts and images, in particular photographs, on this website are protected by copyright. Further reproduction and use of without authorization is usually not consented. If you are not sure or need licensing rights for photographs, for example for publications and commercial use, please contact us.