Activity of Erta Ale, Semeru and Lewotolok

At Erta Ale, images from the Sentinel-2 satellite and the Mirova site show that the significant thermal anomaly, marking the southern pit crater on 29.11.2020, has weakened.

Seifegebreil Shifferaw and a local Adventure and Volcanoes team report that, during a field visit on December 2, they saw the expansion of the southern pit-crater, with a diameter of around 230 meters, and of a depth of about fifty meters. The crater is quite circular, with vertical walls, and the bottom covered with a layer of recent lava in cooling.
This December 4, Sentinel only allows you to see a weak hot spot.

Sources: Sentinel-1, Mirova and Seifegebreil Shifferaw

The PVMBG reports for December 4, 2020 to Semeru:

- 19 eruption earthquakes, with an amplitude of 11 to 20 mm, and an earthquake duration between 34 to 165 seconds.

- 21 collapse / avalanche earthquakes

- 10 blast / emission earthquakes

- 4 episodes of Harmonic tremor

- 1 deep volcanic earthquake

- 1 distant tectonic earthquake.

Source: PVMBG

At Lewotolok, the summit plume was white and gray, thick and 100 to 1000 meters high above the summit on December 4. An eruption was observed at a height of 200-1000 meters above the summit, accompanied by a white / gray plume and a slight roar and incandescence, about 20 meters above the summit.

At night, incandescence is visible at the top.

Thanks to the seismographic records of December 4, 2020, it was recorded:

- 24 earthquakes of eruption

- 90 blast / emission earthquakes

- 15 episodes of non-harmonic tremor

- 2 deep volcanic earthquakes

- 2 distant tectonic earthquakes.

Source: PVMBG