Phivolcs chief advises vigilance vs. vog recurrence

By Ma. Cristina Arayata

October 9, 2023, 8:10 pm

<p>Taal Volcano <em>(File photo</em>) </p>

Taal Volcano (File photo

MANILA – Taal Volcano is clear from volcanic smog (vog) on Monday, but the head of the Philippine Institute of Volcanology and Seismology (Phivolcs) said the public should remain vigilant as recurrence is always possible.

"They (public) should prepare for the possibility of vog recurrence as long as Taal Volcano continues to emit sulfur dioxide," Phivolcs Director Teresito Bacolcol told the Philippine News Agency.

He said Taal Volcano is "very clear" and its main crater is "very visible" on Monday because the situation was windy, causing vog to disperse easily.

Bacolcol clarified that vog could recur and Phivolcs could not say when it would totally disappear.

"It depends on (various factors) such as wind speed, how much S02 (sulfur dioxide) the volcano is emitting, rain and temperature," he said.

One could determine if vog completely disappears when the surroundings are clear and there is no haze and sulfuric smell, he added.

Vog consists of fine droplets containing volcanic gas such as S02. It could persist due to thermal inversion or when layers of the atmosphere don’t mix, causing aerosols to get trapped.

It can cause irritation of the eyes, throat and respiratory tract, the severities depending on gas concentrations and durations of exposure.

Taal Volcano is on Alert Level 1, which means it is still in abnormal condition and should not be interpreted to have ceased unrest nor the threat of eruptive activity.

Entry into Taal Volcao Island, especially the Main Crater and Daang Kastila fissures, and occupancy and boating on Taal Lake are still prohibited. (PNA)