Volcanic Tremor Tracks Changes in Multi‐Vent Activity at Mt. Etna, Italy: Evidence From Analyses of Seismic Array Data

Abstract The mild degassing and effusion that characterizes open-vent volcanoes can be interrupted by
episodes of sustained explosive activity known as paroxysms. Here, we present observations from a seismic
array deployment during the 2021 eruption of Mt. Etna, Italy. During the observation period, degassing
dominated surface activity at the central and northeast summit craters; lava flows, Strombolian explosions,
and fire fountaining, accompanied by ash plumes, characterized eruption in the southeast sector of Mt. Etna.
Seismic array locations showed changes associated with shifts in the style and location of activity across
multiple craters at Mt. Etna. We observed changes in array locations between the north-northeast and southeast
directions that consistently anticipated the onset of paroxysmal activity in the southeast sector. Our results
demonstrate the potential of seismic arrays to resolve vent-specific activity and shed light on precursory
patterns leading up to paroxysmal activity.