Activity of Sangay, Anak Krakatau and Etna.

In Ecuador, the surface and internal activity of Sangay remains unchanged, and qualified as "High".

On May 5, IGEPN noted 7 explosions, and ash emissions could be observed towards the southwest.

VAAC alerts were recorded with heights of 870 meters above the level of the crater and in a southwest direction.

On the southeast flank, the lava flows remain active, and thermal anomalies are reported by Mirova of VRP 90 MW on May 4 at 6:55 p.m., and of VRP 13 MW on May 5 at 4:20 a.m.

A lahar signal was recorded in the volcanic station on the afternoon of May 4, with a duration of 3 hours.

Sources IGEPN and VAAC Washington.

Seismic activity remains high on May 5, 2020 at Anak Krakatau, although slightly down from the previous day with:

- 26 blast earthquakes, with an amplitude of 3-22 mm and an earthquake duration of 6-82 seconds.

- 148 low frequency earthquakes, with an amplitude of 4 to 30 mm and the duration of the earthquake from 4 to 14 seconds.

- 8 hybrid earthquakes, with an amplitude of 6 to 9 mm, the S-P is not observed and the duration of the earthquake is 5 to 10 seconds.

- 4 episodes of continuous tremor with an amplitude of 0.5-8 mm, dominating 2 mm.

The activity level remains at 2 / waspada

Sources: PVMBG & Magma Indonesia

In the week of April 27 to May 3, Etna presented a strombolian activity to Voragine (VOR) and to the new southeast crater (NSEC).

At La Voragine, an inspection on April 30 revealed that the effusive activity of the mouth of the principal cone had stopped, in progress since September 12, 2019, and the lava field is being cooled.

Strombolian activity continues on the other hand at the level of the intracrateric cones of the VOR, with gray-black ash emissions several hundred meters high, during the main cone explosions. During the night of May 3-4, the strombolian explosions from the VOR crater appeared particularly energetic, and the coarse material produced fell outside the edges of the crater, settling on the southern flank of the Bocca Nuova crater. .

It was also observed that the depression that formed inside the BN of the crater has increased compared to what was observed during the inspection of April 18, 2020.

During the week, a pulsatile degassing of the new Southeast crater continued. The presence of flashes at night showed that strombolian activity continued at the level of the "saddle cone", without expelling incandescent materials. Sometimes this activity was accompanied by the emission of reddish ash, quickly dispersed in the atmosphere.

Source / INGV OE - weekly bulletin 27.04 / 03.05.2020