The lava delta continues to be fed by the active lava flows, which show some stability in that they are largely confined to within previous lava flows. However, there are also localised breakouts onto previously unaffected land. The lava delta has reached a thickness of 24 m and is now beginning to spread laterally. Surface activity at the main cone continues to show a mixed mechanism with strombolian activity from multiple vents in the main cone, and more effusive Hawaiian activity from a vent at the base of the NW sector on the main cone, with occasional phreatomagmatic pulses too. Throughout the morning of the 30^th, an extensive fumarole field developed on the NE flank of the main cone. The continued presence of a thermal inversion is hampering the dispersal of volcanic gases and ash, leading to a decrease in air quality in the Aridane Valley. SO2 concentrations in Tazacorte peaked at ‘very high’ levels (>500 μg/m3) at 8:00 am local time and increases in SO2 concentrations have also been observed in Los Llanos de Aridane, along with reports of a ‘rotten egg’ smell, although these values do not currently represent a health hazard.

Earthquake activity continues to be concentrated near where the precursory seismic swarm began on the 11^th September, as well as some earthquakes surrounding the eruptive centre. In total, 11 earthquakes were recorded, peaking at 3.5 mbLg. The ash plume height exceeds 2500 m, and the SO2 emissions are measured at 8,700 tons per day. Deformation continues to show a long-term trend of stability at all stations, and tremor also remains stable, at medium levels.

A thermal image showing the front of the lava delta, where it meets the sea. The temperature scale is in degrees Fahrenheit. Image credit: INVOLCAN

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