Shortly after the previously reported major event, which was first seen as a large ash plume rising from the area, a new lava flow started to emerge from a vent in the summit area, descended on the Sciara del Fuoco and reached the sea. How large it is is still unclear, but the fact that it reached the shore quickly suggests it might have an important rate of lava flow.
It came as a result of what happened immediately before: According to the latest information from the National Institute of Geophysics and Volcanology (INGV) in Catania, explosive activity increased from 2.47 pm local time at the northern vents (on the side of Stromboli village). At 2.51 pm, this culminated in a pyroclastic flow that reached the coast and traveled out above water for about 1 km beyond the coastline (!), while the associated ash plume rose to 1.5-2 km height. Pyroclastic flows are deadly, turbulent hot avalanche of lava rock fragments of all sizes embedded in a mixture of turbulent gas and ash racing down slopes.
Video of the flow:
Likely, the reason for this flow was the sudden accumulation and destabilization of the upper crater area, resulting in a partial collapse. Monitoring instruments recorded significant deformation of the Sciara del Fuoco (a result of internal magma movement and release).
INGV also noted that following the main event, other, but smaller pyroclastic flows and rockfall episodes occurred in the following time, at 3.02, 3.04, 3.09, 3.13 and more until around 3.35 pm. Most of these also were accompanied by stronger explosions at the summit and produced modest ash plumes, but apparently did not extending beyond the shoreline.
To conclude from the observed data is that it seems that we witnessed the arrival of a significant batch of fresh magma in the upper conduits of the volcano. How large it is and how well supplied from deeper reservoirs will likely dictate how long the lava flow remains active and how activity will evolve in the near future. Previous lava flows on the Sciara observed in previous years were mostly rather short-lived, but often came in series during periods lasting several days to a few weeks. The best example and a likely candidate to compare probably could be the activity during the summer of 2019, characterized by two very large explosions in July and August and following periods of intermittent lava flows on the Sciara.
