Strombolian explosions at snow-clad Etna volcano, Italy

Since the early hours of November 24, 2023, Mount Etna has exhibited intensified Strombolian activity at its SE Crater, as observed by INGV-OE. Over the following days, this activity persisted, marked by modest ash emissions and fluctuating seismic intensity, with the Aviation Color Code maintained at Orange.

On November 24, 2023, at 03:36 UTC, the INGV-OE reported an increase in Strombolian explosive activity at Mount Etna’s SE Crater, with volcanic ash dispersing in the NNW direction. Medium-high intensity infrasonic events were localized in the SE Crater area, while ground deformation measurements remained stable.

The following day, November 25, Mount Etna continued to display moderate Strombolian activity. Ash emissions, although modest, were notably dispersing eastward near the summit. Infrasonic activity showed a decrease in both occurrence rate and energy.

The sources of tremor and infrasonic events were still concentrated around the SE Crater, with clinometric data indicating no significant ground deformations.

By November 26, 08:34 UTC, INGV-OE reported the continuation of Strombolian-type eruptive activity, confined to the proximal area of the crater. The regime of this activity varied in intensity and explosion frequency. Ash emissions produced during these explosions rapidly dispersed in SE direction.

Volcanic tremor amplitude showed rapid oscillations between medium and high values. However, due to strong winds since the afternoon of November 25, an accurate assessment of infrasonic event rates and localization was challenging. Ground deformation signals recorded by the clinometer network showed no significant changes.

Strombolian activity at #Etna's Southeast Crater on the morning of 24 November 2023, seen from Piano Vetore, 6 km to the southwest of the crater. pic.twitter.com/jpJBjNIJhJ

— Boris Behncke (@etnaboris) November 25, 2023

Strombolian activity at #Etna's Southeast Crater on the evening of 24 November 2023, filmed from Piano Vetore, 6 km to the southwest of the crater. pic.twitter.com/yWx8GgtcuP

— Boris Behncke (@etnaboris) November 25, 2023

This recent sequence of events follows a period of intensified activity at Mount Etna, which began with a strong explosive eruption marked by towering lava fountains. As reported on November 13, 2023, this surge in activity led to the elevation of the Aviation Color Code to Red.

During that phase, Etna’s eruptions were characterized by high-intensity explosive events, leading to widespread ash dispersion and concerns for air travel safety. The current observations by INGV-OE, though showing ongoing activity, indicate a somewhat moderated state compared to the peak activity witnessed earlier.

References:

¹ INVIO COMUNICATO GENERICO DI ATTIVITà VULCANICA – INGV-OE – November 24 – 26, 2023

² Strong explosive eruption, lava fountains at Etna volcano, Aviation Color Code raised to Red, Italy – The Watchers – November 13, 2023

Featured image credit: Boris Behncke/INGV