Updated lava flow field map
The good news is that the larger the lava field is, the more likely it is that new lava will rather be added on top of it instead of covering new areas. In fact, the activity at the sides of the lava flow field has slowed down; only about 1.9 hectares were covered by new lava flows and no new buildings damaged during a 24 hours interval.
La Palma volcano eruption update: strong activity this morning comes after uptick in earthquakes
This seems to correlate with an increase of earthquakes in the last 24 hours, after having being reduced in numbers yesterday. There were 4 quakes between magnitudes 4.0-4.7 alone in addition to 130 ones at magnitudes around 2.5-3.9.
One of the magnitude 4 quakes occurred early this morning at shallow depth of 13 km, which is thought to be the main reservoir of the magma before it rises to the vents.
Quakes precede phases of intensification?
It seems that such upticks of quake activity precedes phases with increased lava supply several hours later. This might fit into the following model: first, magma pressure at depth increases either by surges from new magma arriving there or from temporary blockages in the paths above, preventing a sufficient release of it at the eruption; then, the pressure on the surrounding rocks create new cracks and paths, which shows up as quakes. 3rd, the magma then then rises through new and existing conduits until it reaches the surface hours later.
Latest lava flow map
La Palma volcano eruption update: dramatic and rapid ground uplift, while surface activity calms down temporarily
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.
La Palma volcano eruption update: eruption with no end in sight, continues at high intensity
The mixed explosive-effusive activity paired with high rates of magma reaching the surface causes frequent small and sometimes larger changes of the geometric configuration at the growing cone, as rapid accumulation works against the forces of gravity, drag of material ejected and flowing away and parts that become undermined by formation of tubes etc.; currently, at least 4 or 5 vents are active aligned in a row, with different behavior as the magma pressure varies with the height of the vents themselves and the complex interactions of the rising gasses and the fluid magma in the conduits.
To get an impression, watch the activity at the vents filmed by drone from the government today:
#ErupciónLaPalma Imágenes en las que se observan las coladas de desborde del conelete así como su velocidad de descenso desde el cono principal, tomadas hoy por los drones del @IGME1849 y #GES de @AdmPcasGobcan pic.twitter.com/wNBfNgTVAv— 1-1-2 Canarias (@112canarias) October 25, 2021
Concerning the most significant instrumental data, there are no signs of a soon end in sight either. Instead, earthquakes have slowly increased not in size, but in numbers. During the past 24 hours, there were 103 quakes of magnitude 3.0-3.7 and 156 quakes between 2.0 and 3.0. The location remains the same as before,- most at around 12 km depth under the central part of Cumbre Vieja and a few ones in the deeper layer around 35 km depth.
Ground deformation also suggests that magma pressure from below is stable, with no clear trend. This suggests that there is still supply of magma from deeper sources to balance the erupting volumes, or, in other words, the eruption is at an equilibrium and might go on for a while still.