La Palma volcano eruption update: dramatic and rapid ground uplift, while surface activity calms down temporarily
Tue, 26 Oct 2021, 20:5420:54 PM | BY: T
Lava fountain from the main vent at the La Palma eruption this evening (image: kimedia webcam)
Ground deformation at LP03 and LP05 stations showing the uplift today (image: IGN)
Current seismic signal LP01 station (image: IGN)
Compared to yesterday, the visible activity at the vents has decreased somewhat today. Only one of the vents seems now to produce pulsating lava fountains and an ash plume has been rising to approx. 2-2.5 kilometers today. Surface lava flow activity near the vents has decreased a lot as well.
Numbers of daily quakes showing the marked decrease today (image: IGN)
Last evening, following hours of intense activity from at least four vents, parts of the western crater walls at the vents collapsed and gave way to short-lived floods of lava on the slopes of the cone. Whether or not the visible decrease is caused by a decrease of magma supply at the moment, remains unknown.
One factor to consider is that such larger re-configurations at the vent create new conditions so that the arriving magma might more easily find new ways to enter existing or create new tubes, and remain hidden from direct view.
However, it is likely that currently, indeed less magma is reaching the surface, but is this a sign the eruption might be waning? Likely not, unfortunately: instead of slowly deflating (as the magma chamber is being emptied by the eruption), the ground near the eruption site has been rising significantly again. And quite dramatically so. If the station LP3 has a correct measurement, the ground rose 10 cm (!) since yesterday. If that amount of inflation is caused by more magma arriving from depth into shallower reservoirs than what is erupting, it would fit the picture of less activity at the vents.
It also fits the observation that the volcanic tremor remains high, at similar levels as the past days, meaning that the system is still being supplied sign significant amounts of magma each day.
What is not easy to interpret in this model is that earthquakes have decreased significantly in numbers at the same time. Compared to the past days'average, less than half as many quakes occurred in the past 24 hours, "only" about one hundred... To add to all this, one of the strongest quakes so far at magnitude 4.8 or 4.9 occurred this afternoon at 5.25 p.m. at 40 km depth. It was widely felt on the whole island.
Tue, 26 Oct 2021, 09:00
La Palma Volcano Volcanic Ash Advisory: ERUPTION AT 20210919/1410Z ASH EMISSION ONGOING OBS VA DTG: 26/0900Z to 8000 ft (2400 m)
Tue, 26 Oct 2021, 03:00
La Palma Volcano Volcanic Ash Advisory: ERUPTION AT 20210919/1410Z ASH EMISSION ONGOING OBS VA DTG: 26/0300Z to 8000 ft (2400 m)