La Palma volcano eruption update: eruption continues with vigorous lava fountaining and voluminous lava flows
Sun, 3 Oct 2021, 10:2410:24 AM | BY: T
Lava fountain from the NW summit vent at La Palma last night (image: Tom Pfeiffer / VolcanoDiscovery)
Volcanic tremor amplitude (image: IGN)
Latest lava flow map (image: Copernicus)
Recent quakes under La Palma (image: IGN)
The eruption continues at impressive intensity. The lava output rate remains very high and volcanic tremor is stable at high levels.
The valley seen from El Time last night
The new lava flow from the separated vents just below the northwestern base of the erupting cone slowly make their way through so-far untouched land north of the existing flow field, destroying additional buildings and other infrastructure so far spared. The flow forms an impressive channel of approx. 50 m width and there is no explosive activity at its vent. (Check the latest lava flow maps in high res at the Copernicus mapping site)
At the cone itself, approx. 8 vents in total are active producing several lava flows, some of which seem to go directly into lava tubes, others overlapping older flows or feeding more or less stable lava channels. Some of the lava still finds its way to the sea entry, which is growing slowly.
The upper vents produce tall pulsating lava fountains, with moderate ash plumes. When observed yesterday evening, the lower vent on the NW flank of the cone, which had been a site of near-constant low, liquid fountaining gradually ceased to produce fountains, but it seems that the energy then went to the NW summit vent, which started an impressive show of violent, near vertical fountaining reaching 3-500 m height:
A total of approx. 50 million cubic meters of lava have been emplaced so far, much more than originally estimated the eruption would be able to produce. This likely has to do with the continued earthquake activity that could suggest magma supply from a deeper source.
Earthquake activity continues
The quake activity is quite intense. During the past 48 hours, the monitoring institute recorded 22 quakes of magnitudes 3.0-3.6, most of them felt, and 45 quakes between magnitudes from 2.0-2.9. There are many more smaller quakes, but due to the strong tremor signal of the eruption acting as high background noise, they cannot be detected in the data.
The earthquakes are currently located mostly at 10-15 km depth beneath the southern part of the island, in a similar region as the earthquakes in the beginning of the seismic swarm that preceded the eruption. This is the area between the upper mantle and crust of the island, where magma from the deeper source intrudes into the volcanic edifice.
There is no clear trend visible in the location of the quakes; they seem to remain stationary in this area, which might be explained that the new intrusions that likely occur there are able to use the existing pathways of magma through the island edifice. If there is a continuous supply from the mantle source, the eruption could last for much longer than expected, but this is speculation.