Due to cooling and the infilling of topographic lows, the lava flow fronts have slowed significantly, and now advance at around 4 metres per hour. The total area affected by the lava flow stands at 140 hectares, with the flow fronts measuring 600 metres across. The episode of increased explosiveness that began at 7pm local time on the 21st ended at 2am local time and coincided with a small collapse of a portion of the cone. Strombolian activity continues producing both ash and lava flows from multiple vents in the vicinity of a principal cone that has formed around the most active vents. In the current state, up to 9 vents along one fissure have been observed by the authorities, although on average only 4 of these are active at any one time. This activity is emitting over 12,000 tons of SO2 per day up to 3000 m, although the amount of SO2 released per day is thought to be an underestimate according to PEVOLCA, as such ground-based measurements cannot be used to observe the full extent of the plume, unlike satellite observations.

As the eruption enters its third day, no casualties or personal injuries from the eruption continue to be reported. However, the first provisional damage assessment has been published which estimates that 185 buildings have been affected, 63 of which are homes according to the Land Registry. The lava flow now has two fronts; a northern front which is closer to Todoque, and a southern front which is largely stopped for the moment. The advance of the active flow front is slowing relative to previous days, however.

The new eruption continues with strombolian activity and lava flows being produced from 4 vents along an eruptive fissure, although a principal cone has been formed. The opening of new vents cannot be ruled out, with the final active vent opening at 7:56 pm local time and showing a more effusive character. The lava flows have reached halfway to the sea, although the flow fronts have slowed markedly relative to their initial velocity. Latest estimates give a velocity of 200 metres per hour, and they are expected to reach the town of Todoque within the next couple of days. However, it is uncertain when the flows will reach the sea, although the maritime authorities have extended the oceanic exclusion zone to two nautical miles, for security as well as safety reasons. The exclusion zone has also been extended to include Tacande in the municipality of El Paso as a new eruptive vent 900 metres from the main one has opened, forcing the evacuation of more people, moving the total number of evacuees to approximately 5,500. As well as people, a priority of the authorities is to transfer livestock out of the path of the eruption, including 400 goats in addition to pigs and cattle so far.

At 15:12 local time, a basaltic fissure eruption began, with the coordinates of the first emission point being 28º36’N, 17º52’W. The eruption has shown phreatomagmatic pulses, especially during the first few hours, characterised by ash-and-steam-rich plumes, which reached heights of 1500-3000 m, although predominantly shows a typical strombolian mechanism. Initial estimates indicate the SO2 emissions from the activity could be between 6,000-9,000 tons per day.

A PEVOLCA meeting today chaired by Justice, Security and Public Administrations Minister Julio Pérez on the evolution of the seismic activity on La Palma covered among other things advancing actions for a possible future evacuation of the population in the affected municipalities of Fuencaliente, Los Llanos de Aridane, El Paso and Villa de Mazo. The Cabildo de La Palma, who were in attendance, have activated their island-wide PEINPAL Emergency Plan as a preventative measure. Furthermore, an observation flight over La Palma has been coordinated for the monitoring of the ongoing activity. As well as the island-wide emergency plans, the town councils of the affected municipalities (Fuencaliente, Los Llanos de Aridane, El Paso and Villa de Mazo) have also activated their local emergency plans.

Today, a cluster of 11 earthquakes at 9-14 km were recorded in the south of La Palma close to the Cumbre Vieja ridge, starting at 3:18 am local time. The largest event so far was a mbLg 1.5 earthquake and 11 km depth. This new seismic swarm is the first that has been detected since earthquake swarms in June and January 2021, which were largely clustered in similar areas but at depths deeper than 20 km. The swarm represents the 9th seismic swarm in southern La Palma since anomalous seismic activity began in the area in October 2017, which is thought to be related to magmatic reactivation of Cumbre Vieja. The shallow depth of these latest earthquakes, as well as the consistent locations with other swarms, are the most significant features, although the timescales nor the potential occurrence of any magmatic reactivation cannot be determined in the short-medium term.

Miguel Ángel Morcuende, head of the Environment and Emergencies service of the Government of La Palma, has been appointed technical director of PEVOLCA and will be responsible for directing and coordinating all actions carried out under the Plan itself. To meet the telecommunications demands that an emergency could bring, the government has decided to upgrade the existing Canary Islands Emergency and Security Network (RESCAN).

As the seismic swarm continues to intensify, PEVOLCA maintains the yellow traffic light in the municipalities of El Paso, Los Llanos de Aridane, Mazo and Fuencaliente, although comments that there is still no evidence of an imminent eruption. Over the last couple of days, the seismicity has become displaced to the northwest relative to the focus at the beginning of the swarm, and the average depth has decreased and is now between 6-8 km. Additionally, today some lower magnitude earthquakes have been detected much nearer the surface (1-3 km).

Today, a cluster of 11 earthquakes at 9-14 km were recorded in the south of La Palma close to the Cumbre Vieja ridge, starting at 3:18 am local time. The largest event so far was a mbLg 1.5 earthquake and 11 km depth. This new seismic swarm is the first that has been detected since earthquake swarms in June and January 2021, which were largely clustered in similar areas but at depths deeper than 20 km. The swarm represents the 9th seismic swarm in southern La Palma since anomalous seismic activity began in the area in October 2017, which is thought to be related to magmatic reactivation of Cumbre Vieja. The shallow depth of these latest earthquakes, as well as the consistent locations with other swarms, are the most significant features, although the timescales nor the potential occurrence of any magmatic reactivation cannot be determined in the short-medium term.

Today, in the wake of the intensifying seismic swarm on La Palma that began on the 11th September, the Government of the Canary Islands have activated the Scientific Committee of the Special Plan for Civil Protection and Attention to Emergencies due to Volcanic Risk (PEVOLCA). Alongside this activation, the volcanic traffic light alert system has been raised from green to yellow in the municipalities of Fuencaliente, Los Llanos de Aridane, El Paso and Mazo. The yellow traffic light allows for an intensification of communication to the population, volcano and seismic monitoring, as well as increased surveillance.