La Palma volcano eruption update: continuing ash emissions to 4000 m altitude causing increasing problems
Although the activity has been much less noisy recently, the continuous gas and ash emissions, often in combination with little wind has been causing lots of ash fall and poor air quality in the Ariadne Valley, which is an increasing problem.
The lava flows have advanced a bit along the active northern fronts, but the northwestern flow has not yet created a new sea entry (although it might occur soon).
Tremor remains at similar levels as during the past weeks, even a bit above average.
Earthquakes continue as well at similar numbers as before, in the same areas - mostly in 10-15 km depth under the center of Cumbre Vieja, and few, but often stronger ones at 35-40 km depth. IGN recorded a total of 101 quakes during a 24 hour interval, including 7 felt ones, with the strongest being a magnitude 4.6 event at 12:57 a.m. early today.
Deformation is showing a weak trend of deflation, suggesting that the magma reservoir is slowly emptying.
Annotated latest lava flow map
Lava flow (or lobe) 9C has developed 3 arms. One of them, the one located more to the north, traveled about 450 m since yesterday's position and is likely going to reach the ocean in the course of this evening, destroying on its way banana fields. The flow destroyed the SPAR supermarket in La Laguna, but fortunately only few other structures.
As to the northern flow (10A and 10B), the flow fronts appear to have stopped. The flow arm 10C, which advanced a lot yesterday has almost stopped, advancing only a few tens of meters.
New lava outbreaks have appeared in the highest part of the flow field; the most energetic of which is shown as 10D arm.
La Palma volcano update: eruption continues with slight decrease of activity
At the vents, a lava flow continued to be active and explosions at the upper vents produce pulsating fountains with strong ash emissions. The ash plume has been rising nearly vertically today due to the absence of winds, reaching an altitude of approx. 4000 m.
The advance of the lava flows has slowed somewhat. The northern flow front, west of Montagna La Laguna and directed westwards, has been advancing at rates of approx. 15 m per hour and is now close to or already at the coastal cliff.
Deformation shows a trend of deflation at the station closest to the eruptive center, suggesting that the output of lava now exceeds supply of it from depth. This could be seen as a first sign the eruption likely has passed its peak.
Así está la erupción a las 11,45 hora canaria / There is the eruption at 11,45 Canarian time pic.twitter.com/wUOjhXzRas— INVOLCAN (@involcan) October 17, 2021
Earthquake activity remains significant, although also decreased a bit compared to previous days. During the past 24 hours, there was 1 quake of magnitude 4.0, 24 quakes between 3.0 and 4.0, and 51 quakes between 2.0 and 3.0.
La Palma volcano eruption update: eruption continues at high intensity, threatening La Laguna and airport operations
Volcanic tremor, as an indicator of magma flux, remains high and has increased a bit compared to the previous days.
Most notably, lava advance has been occurring at 3 lava flow fronts. Among these, two active fronts remain south of La Laguna, which are likely to merge and could soon reach the sea as well. One of these lava flows surpassed the mountain of La Laguna yesterday and was reported to be fed by a channel where lava flows at speed of 1300 m per hour:
A las 11,00 hora canaria la colada de lava que superó ayer la montaña de La Laguna sigue recibiendo material lávico que fluye a 1300 m/h / At 11.00 Canarian time the lava flow that surpassed the mountain of La Laguna yesterday continues to be fed by lava that flows at 1300 m/h pic.twitter.com/YZR6fwWjkw— INVOLCAN (@involcan) October 16, 2021
A third active front that advanced towards the northwest is of particular concern. Yesterday, it had reached the El Cumplido road and slowly continued its path. Today, it continued moving through the industrial center of Tajuya and approaching the center of La Laguna, but it is hoped that topography will divert it more towards the west before reaching La Laguna's center.
La lava sigue fluyendo por el polígono industrial de Tajuya en una secuencia grabada a las 13,00 hora canaria / The lava continues to flow through the Tajuya industrial park in a sequence recorded at 13,00 Canarian time pic.twitter.com/P4ESzhvYWf— INVOLCAN (@involcan) October 16, 2021
Continued ash emissions, airport affected
At the vent, activity remains dominated by lava effusion with less explosions than before, although it still generates a plume rising to 4000 m altitude. Today, some ash fall reached the airport, affecting operations and the airspace between La Palma, La Gomera and the North of Tenerife.
New vent southeast of cone
Yesterday, a new vent was reported to have appeared 300-300 m southeast of the main cone yesterday afternoon; according to new information, it was apparently an older vent active early on in the eruption that was reactivated, but decreased its activity again toda. It mainly emitted gas and ash, but apparently no or little lava flows.
Video donde Ramón Casillas, miembro debla ULL en #PEVOLCA, confirma la nueva boca al Sureste del volcán actual. @112canarias @CabLaPalma @Marianohzapata #ErupcionLaPalma #VigilanciaLaPalma #volcanesdecanarias pic.twitter.com/s4091IacVF— Volcanes de Canarias (@VolcansCanarias) October 15, 2021
Gas emissions, seismic activity, ground deformation
Sulfur dioxide emissions were measured at 2882 tons per day, considerably lower than on previous days.
On the other hand, seismic activity increased again in the number and average size of quakes, clustered in two areas (10-15 km as well as 35-40 km below the volcano). The strongest-so-far quake was a widely felt magnitude 4.5 event early this morning.
As to the quakes in the shallower group, a weak trend is becoming visible in that they tend to migrate to the northwest, i.e. closer to the current eruptive centers.
Ground inflation observed in the past days decreased again to the levels observed since the start of the eruption.