Taal volcanic smog blankets Batangas towns

MANILA, Philippines — The Philippine Institute of Volcanology and Seismology (Phivolcs) is monitoring ongoing degassing activity in Taal Volcano, the second time in less than a week.

Phivolcs said that significant volcanic smog or vog has formed over the Taal caldera and surrounding areas since Tuesday, forcing the suspension of classes in nearby towns.

The agency has monitored active degassing of Taal’s main crater in the past 24 hours, with visible upwelling of volcanic fluids in the main crater lake and voluminous steam-rick plumes that rose 2,000 meters.

Sulfur dioxide flux measured 7,680 tons on the same day, slightly lower than the 9,391 tons per day monitored last Monday.

“Vog can be expected to persist over the Taal region while degassing activity, weak wind movement and humid atmospheric conditions prevail,” Phivolcs said in an advisory.

“In addition, acid rain can be generated during periods of rainfall and volcanic gas emission over areas where the plume disperses, causing damage to crops and affecting metal roofs of houses and buildings,” it added.

Phivolcs warned of increased and continuous degassing activity since the evening of June 3.

The state volcanology bureau said that Taal remains under Alert Level 1, “which means that it is still in abnormal condition and should not be interpreted to have ceased unrest nor ceased the threat of eruptive activity.”

Under Alert Level 1, sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall and lethal accumulations or expulsions of volcanic gas can occur.

Phivolcs said an uptrend in monitored parameters that could signal renewed unrest may warrant raising to Alert Level 2.

The agency warned that vog, which consists of fine droplets containing volcanic gas such as sulfur dioxide, which is acidic, could cause irritation of the eyes, throat and respiratory tract.

It noted that severity of irritation could depend on gas concentrations and durations of exposure by the individual, and individuals who suffer from health conditions may be particularly sensitive to vog, including those with asthma, lung and heart diseases, the elderly, pregnant women and children.

Phivolcs also advised residents to limit their exposure by staying indoors and shutting doors and windows to block out vog.

It emphasized that entry into Taal Volcano Island or the permanent danger zone remains strictly prohibited.

Wearing of N95 face masks and drinking water to reduce throat irritation can also be applied, as Phivolcs advised individuals to seek help if they experience serious effects.

Several areas in the province of Batangas suspended classes yesterday due to volcanic smog or vog coming from Taal Volcano.

Among those that suspended classes in all levels in public and private schools were the local governments of Laurel and Talisay.

Also suspended were classes in Barangays Banyaga, Barigon and Bilibinwang in Agoncillo until tomorrow.

Mayon dome grows

Meanwhile, the lava dome that is blocking the crater of Mayon Volcano in Albay continues to grow, triggering rockfall events for several weeks until yesterday, according to Phivolcs.

Paul Alanis, Phivolcs resident volcanologist based at the Lignon Hill Observatory, said seismographs around Mayon detected at least 46 rockfall events, which indicate that the lava dome at the volcano’s crater is continuously growing in volume.

“Although we did not conduct yet an aerial survey to determine the exact size of the dome at present, the unabated rockfalls recorded by our seismographs clearly indicate that the dome keeps growing,” Alanis told The STAR.

He said their instruments last measured the volume of the lava dome last May 9 at 83,000 cubic meters, which is bigger than the volume measured last year.

“And a total of nearly 164,000 cubic meters of volume of the lava dome has been measured already since Aug. 20, 2022,” he added.

Phivolcs decided to raise Mayon’s Alert Level 1 to Alert Level 2 at 10 a.m. last Monday when they observed the continuously increasing volume of the lava dome and the inflation of its surface, according to Alanis. – Janvic Mateo, Cet Dematera