The activity at the volcano has been fairly stable over the past weeks. When observed during repeated visits in mid to end of October, when we accompanied several small groups to the volcanoes of Italy, including Stromboli island, it was characterized by typical strombolian-type explosions from mainly two vents:
The most active vent has been the prominent cone in the northeastern crater terrace, having spatter-rich and ash-poor explosions every 15-20 on average. Some of the explosions ejected glowing lava bombs to heights of 150-200 m above the vent, and were accompanied by detonation sounds and shock waves that can be felt all over the island.
During the night, weak to moderate lava spattering could be observed occurring at this vent most but not all of the time.
The second most active vent is located in the western crater terrace and typically ejects ash plumes with only few incandescent or coarse material. Most of these emissions are rather passive, but sometimes also occur in the form of sudden and comparably violent explosions. During these, ash-rings were occasionally observed. These are ring vortexes likely caused by the sudden ejection of a dense ash-gas mixture from a circular vent that result in a circular eddy that can remain stable over minutes while drifting into the air.
In the central area of the crater, a small hornito-shaped vent occasionally produced smaller, candle-shaped jets of lava, but often showed weak glow as well as mild spattering. Jet-engine like degassing sounds without visible solid ejecta were sometimes heard as well, and probably came from this vent.
Additional note: Residents on the island report to us that the sounds of explosions felt has somewhat changed recently, „as if coming from deeper inside“, but we are unable to attribute this description to any significant observed change in activity.
