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 21^st 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.

Concerning geophysical parameters, the volcanic tremor has seen a decrease in amplitude attributed to the concentration of the activity around a smaller area, compared to the first hours of the eruption. Deformation for the moment seems to have stabilised, and the maximum measured inflation since the start of the seismic swarm remains the 28cm measured by InSAR (Interferometric Synthetic-Aperture Radar). Earthquake activity remains at a low level, with 7 earthquakes recorded, peaking at 3.0 mbLg.

The latest maps of the lava flows (accurate as of the 21st September) showing the roads and buildings destroyed (red dots) and damaged (yellow dots). Image credit: Copernicus EMS

Sources: Government of the Canary Islands, PEVOLCA, Involcan, IGN, DSN, Cabildo La Palma, 112 Canarias, Tolouse VAAC