Year: 2020

Taal: Seismic high, SO2 low

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The situation on the Taal is still exciting. Yesterday and today the VAAC registered one ash cloud each, whose ascent heights could not be determined. The seismic activity is still high. The Taal network recorded 486 tremors in the last 24 hours. The strongest one had a magnitude of 2.7 and was not noticed by local residents. The seismic activity is probably caused by rising magma. The ground deformations are correspondingly large. Especially in the southwest and north of the caldera there are ground elevations which are probably related to the inflation of magmatic fluids. In the eastern part of the caldera, however, the ground has been sinking.

Sulphur dioxide emissions are disproportionately low, at only 224 tonnes per day. One would expect at least 10 times the current value. Philippine volcanologists speculate about plugs in the production vents that prevent the gas from escaping. However, such plugs would not only block the sulphur dioxide, but also impair the entire gas exchange. The result would be an enormous increase in pressure in the earth’s interior. Alternatively, the soil deformations could not be caused by magma, but by other fluids. Water would be one possibility. This would also be an answer to the question where the disappeared water of Lake Taal has gone: Last week the lake level dropped a few centimetres.

Etna: Summit activity continues

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The activity of the volcano Etna on Sicily (Italy) continues and is even worth seeing, as the video below demonstrates. The intracrater cone of Voragine is strombolian active and continues to grow slowly. From a vent on the lower flank of the cone a lava flow is flowing, which splits into 2 arms. They flow into the neighbouring crater Bocca Nuova and form a rare lava fall there.

From the technical point of view the eruption manifests itself in an increased tremor and moderate thermal signals. MIROVA registered radiation with a power of 44 MW. In addition, the INGV thermal imaging camera now shows 2 hot spots in the area of the New South East Crater. It looks as if another vent has become active there.

Taal volcano erupted

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On 12 January, the eruption began with phreatic explosions, which then increased rapidly. A violent eruption caused ash clouds to rise into the stratosphere. The eruptions manifested from the main crater of Volcano Island, which is located in the middle of the Taal caldera. The ash not only rained down in the immediate vicinity of the volcano, but even reached the capital Manila. The airport was closed.

In various places, house roofs collapsed, which could not withstand the weight of the ash. The following day, lateral vents opened on the flank of Volcano Island. These generate smaller eruptions. PHILVOLCS also reported short lava flows of highly viscous lava.

The eruption was announced by numerous earthquakes. Their frequency increased in the last weeks and reached peak values of 140 quakes per day. Shortly before the eruption the magnitude of the earthquakes increased and reached M 4.0.

The authorities reacted quickly and ordered evacuations. A 14 km long exclusion zone was established. It largely encloses the Taal Lake, which is located in the caldera.

Translated with www.DeepL.com/Translator (free version)

Etna: Activity increases

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The activity on Etna in Sicily seems to be slightly increasing again. The LGS registered sounds that could be caused by explosive activity with its infrasonic microphones and issued an “early warning” of level yellow. Visual confirmation of the activity was provided in the form of images posted by Dr. Boris Behncke of the INGV. They are similar to what we last saw of the volcano in December. There is an active vent in the Voragine that supports glowing tephra. Small ash clouds rose from the New South East Crater and the Northeast Crater. MIROVA registers weak to moderate heat radiation. The tremor is normal.