In the late evening of 13 December 2020, the surveillance networks of the INGV Etna Observatory recorded a sudden increase in the amplitude of the volcanic tremor, accompanied by an increase in Strombolian activity at the South-East Crater.
Around 23:00 local time an activity was underway characterized by modest lava fountains with the formation of an eruptive column pushed by the wind towards south-southeast.
The lava jets reached heights around 150-200 m above the eruptive vent. After fifteen minutes, at 23:15, the flank of the cone of the Southeast Crater began to collapse, generating a pyroclastic flow along a few hundred meters in a southwesterly direction.
Shortly after this first pyroclastic flow, a second considerably larger one followed, which traveled about 2 km always in a southwesterly direction. A third and smaller pyroclastic flow occurred at 23:30.
The lava fountain activity lasted for a few tens of minutes and decreased just before midnight. After about an hour, a second phase of lava fountains began, lasting about 10 minutes.
After an interval of modest Strombolian activity, around 02:00 a third phase of low lava fountains began, lasting about an hour, which was followed by a weak Strombolian activity, still ongoing on the morning of 14 December.
The two lava flows, the one on the southern slope of the Southeast Crater cone, which reached the Torre del Filosofo area, and the one on the southwest slope, which expanded on the plateau upstream of the 2002 cones -03 and Monte Frumento Supino, at dawn on December 14th they were cooling down.
Field investigations are underway by staff of the INGV Etna Observatory to characterize the phenomena that have affected the eruptive theater and to sample the erupted products that will be analyzed in the laboratory.
Pyroclastic flows similar to those that have occurred, also called fiery or pyroclastic avalanches, have also occurred in the past years in other sectors of the South-East Crater, for example in conjunction with the beginning of the paroxysmal eruptive activity of November 16, 2006, during several lava fountaining episodes in 2011-2013, February 11, 2014 and March 2017.
The evolution of the phenomena continues to be constantly monitored by the monitoring networks of the Etna Observatory and the Palermo Section.
Photo 1 – Etna, photo of the paroxysm of the night between 13 and 14 December 2020
Photo 2 – Etna, photo of the activity at dawn on 14 December 2020
Image - frame from the thermal camera at Nicolosi showing the largest of the three pyroclastic flows that occurred at the moment of maximum intensity of the activity.
