In an event unfolding from the evening of June 3 to the early hours of June 4, 2023, Taal Volcano showcased an increased degassing activity, leading to the formation of steam-rich plumes reaching up to 3 000 m (9842 feet) above the Taal Volcano Island. This activity has resulted in significant volcanic smog or vog over the Taal Caldera, affecting local municipalities.
In an advisory issued at 13:00 LT on June 4, 2023, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) noted a significant increase in degassing activity from Taal volcano. This activity was marked by the visible upwelling of volcanic fluids in the Main Crater Lake that produced voluminous steam-rich plumes. These plumes rose to 3 000 m (9842 feet) above the Taal Volcano Island, leading to the formation of considerable volcanic smog, also known as vog, over the Taal Caldera.
Vog, a significant concern due to its health implications, was reported by residents of the Municipalities of Balete, Laurel, and Agoncillo in Batangas. This comes after 5 831 tonnes/day of volcanic sulfur dioxide (SO2) gas emission from the Taal Main Crater on June 1, 2023, a figure that surpassed the previous month’s average of 3 556 tonnes/day (3 917.6 tons/day).
As a reminder, vog consists of fine droplets containing volcanic gas such as SO2, which is acidic and can cause irritation of the eyes, throat, and respiratory tract, with severities depending on the gas concentrations and durations of exposure. PHIVOLCS advises the public, particularly those with health conditions such as asthma, lung disease, heart disease, the elderly, pregnant women, and children, to limit exposure, stay indoors, and protect themselves.
In addition to the health concerns, acid rain, which can be generated during periods of rainfall and volcanic gas emission over areas where the plume disperses, poses a threat to crops and can affect metal roofs of houses and buildings.
Despite the ongoing unrest, PHIVOLCS reminds the public that Alert Level 1 prevails over Taal Volcano. This means that the volcano is still in an abnormal condition and should not be interpreted to have ceased unrest nor the threat of eruptive activity. Sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within the Taal Volcano Island.
PHIVOLCS strongly recommends that entry into Taal Volcano Island, Taal’s Permanent Danger Zone or PDZ, especially the vicinities of the Main Crater and the Daang Kastila fissure, must remain strictly prohibited. Local government units are advised to continuously assess previously evacuated barangays around Taal Lake for damages and road accessibilities and to strengthen preparedness, contingency and communication measures in case of renewed unrest. Furthermore, people are also advised to observe precautions due to ground displacement across fissures, possible ashfall and minor earthquakes.
Taal is one of the most active volcanoes in the Philippines and has produced some of its most powerful historical eruptions. Though not topographically prominent, its prehistorical eruptions have greatly changed the topography of SW Luzon.
The maximum depth of the lake is 160 m (525 feet), and several eruptive centers lie submerged beneath the lake. The 5 km (3.1 miles) wide Volcano Island in north-central Lake Taal is the location of all historical eruptions.
The island is composed of coalescing small stratovolcanoes, tuff rings, and scoria cones that have grown about 25% in the area during historical time. Powerful pyroclastic flows and surges from historical eruptions have caused many fatalities.2
1 Taal Volcano Advisory – PHIVOLCS – June 4, 2023
2 Taal – Geological summary – GVP
Featured image credit: JDP House Tour (stillshot)
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