Activity of Etna and Semeru.

In the late evening of December 13, 2020, after a few days of low levels of activity at the summit craters of Etna, a sudden increase in the amplitude of the volcanic tremor was observed. At the same time, Strombolian activity at the southeast crater has intensified, shifting to lava fountains (see yesterday's article)

In the following hours a paroxysmal episode consisting of three short phases of lava fountains took place; they also emitted lava flows directed towards the south and the southwest, however remaining at altitudes above 2800 m.

A map, established by the Sentinel-5 P satellite of Copernicus, showed evidence of a strong plume of sulfur dioxide.

In addition, field surveys carried out on December 14 by the INGV OE showed significant morphological changes in the cone of the SE Crater, in particular the absence of the southwestern part of the crater due to collapse phenomena. The latter on the night of December 13 generated the three pyroclastic flows. The second pyroclastic flow of 22:16 UTC, which was the most energetic, traveled about 2 km west of Monte Frumento Supino.

Since 12:52 p.m. on December 14, the explosive activity has produced an eruptive cloud that disperses towards the south reaching a maximum quota of about 4 km at sea level.

On the evening of December 14, we observe tall lava fountains and the emission of lava flows to the south and southwest.

A beautiful strombolian activity marked two mouths of the Crater of the South-East (that of the " Saddle " and what is called " New Crater of the South-East "). Sometimes, after a while, activity is visible at the Voragine Crater.

Seismic signals do not show significant changes. The GPS and clinometric networks do not show any significant deformation in progress.

Source: INGV OE

At Semeru, the eruptive plumes and those linked to the collapses could not be observed on December 14 due to the fog.

An avalanche occurred, with a sliding distance of 300 to 1,500 m from the end of the lava flow towards Besuk Kembar and Kobokan.

Thanks to the seismographic records of December 14, 2020, it was recorded:

- 10 eruption earthquakes

- 1 blast / emission earthquake

- 9 episodes of Harmonic tremor

- 1 deep volcanic earthquake

- 6 distant tectonic earthquakes

This December 15 at the very beginning of the day, the lava flow and the summit incandescence were observable.

VAAC Darwin issued an ash scatter advisory at flight altitude 140, as did an orange VONA.

In level II status (Alert), it is recommended for people / visitors / tourists not to have activities within a radius of 1 km from the crater / summit of Mount Semeru and at a distance of 4 km from the direction of the opening of the crater in the south-southeast sector, and to remain aware of pyroclastic flows of avalanches, lava avalanches and lahars along the rivers / valleys that originate at the top of Mount Semeru. The recommended radius and distance will be continuously evaluated in anticipation of any change in hazard symptoms.

Sources: PVMBG & VAAC Darwin