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Earth of fire

Actualité volcanique, Articles de fond sur étude de volcan, tectonique, récits et photos de voyage

Publié le par Bernard Duyck
Publié dans : #volcanic activity

At least 21,780 people have been displaced by the lingering unrest at Taal Volcano over the past two weeks.
The National Council for Disaster Risk Reduction and Management said 6,000 people were still evacuated, while around 16,000 people remained with friends or relatives. The affected residents are from 145 barangays.
Aid worth around 16 million pesos was distributed to evacuees, including family food packages and non-food items such as hygiene and family kits and tents.

Taal volcano island - alert level 2 - photo Philstar

Taal volcano island - alert level 2 - photo Philstar

After the phreatomagmatic eruption in the main crater on July 1, 2021 and nineteen (19) weak phreatomagmatic bursts recorded until July 9, 2021, there was a slowdown in the volcanic activity of Taal. Current turbulence includes renewed seismic activity, a general decrease in volcanic gas evaporation, slow volcanic deflation, and positive anomalies using microgravity. These observations are based on the following signs:

As of July 1, 2021, the volcanic earthquakes recorded by the Taal Volcano Network (TVN) have a total number of 1,201 and have associated forces ranging from M1.8 to M4.6. These include 789 volcanic earthquakes, 365 low frequency events, 27 hybrids and eight (8) volcano-tectonic earthquakes caused by magmatic activity and the hydrothermal region under the volcanic island of Taal (TVI). Most of the earthquakes originated under the main crater and the northeastern part of the TVI indicates the movement of shallow degassed magma, volcanic gas, and hydrothermal fluids in this part of the volcano.

Taal - RSAM and daily earthquakes at 23.07.2021 - Doc. Phivolcs - one click to enlarge

Taal - RSAM and daily earthquakes at 23.07.2021 - Doc. Phivolcs - one click to enlarge

Taal - sulfur dioxide flow at 23.07.2021 - Doc. Phivolcs - one click to enlarge

Taal - sulfur dioxide flow at 23.07.2021 - Doc. Phivolcs - one click to enlarge

The sulfur dioxide flow, measured by Flyspec, averaged 12,161 tonnes / day during the first week of July 2021, with a max. of 22,628 tonnes / day on July 4.

Since July 8 and July 22, the sulfur dioxide rate has fallen to 4,763 tonnes / day.

 

Soil deformation data confirms that hydrothermal activity is taking place below the Taal Fracture Zone, and magma is flowing from the southeastern part to different parts of Taal Volcano Island.

 

In accordance with these criteria, the Phivolcs reduced the alert level from 3 to 2 for the Taal. At Alert Level 2, sudden explosions of steam or gas, volcanic earthquakes, minor ash falls and fatal accumulations or expulsions of volcanic gas can occur and threaten areas in and around TVI. DOST-PHIVOLCS strongly recommends that entry be strictly prohibited on the island of Taal Volcano, the Permanent Danger Zone or PDZ of Taal, especially the surroundings of the main crater and Daang Kastila fissure, as well as the occupation and sailing on Taal Lake.

 

Source: Phivolcs

Turrialba - formation of 2 lakes close to the active crater - Doc. Ovsicori 07/24.2021

Turrialba - formation of 2 lakes close to the active crater - Doc. Ovsicori 07/24.2021

At 11:30 a.m. local time on July 23, 2021, a one-minute eruption was recorded at the Turrialba volcano.

Due to cloud cover, there were no visual observations, but ashfall was reported 3.5 km west of the volcano. This eruption occurred a few hours after the start of a rainy event. The rain is still on the region.

A note: 2 lakes formed near the active crater, under the effect of these heavy rains.

The H2S / SO2 ratio was measured yesterday; it shows a slight decrease compared to the previous week.

 

Source: Ovsicori

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