‘Relative lull’ has PHIVOLCS re-assessing Taal’s eruption scenario

Four days after raising Alert Level 4 at Taal Volcano, PHIVOLCS on Thursday said that it would now evaluate whether an explosive eruption was in the offing or its volcanic activity would be a "long-term trend".

Mariton Bornas, the chief of PHIVOLCS' Monitoring and Eruption Prediction Divison, said PHIVOLCS expected an explosive eruption scenario due to the developments on Sunday when the alert levels were raised in just a matter of hours.

"Kasi 'yung una po naming scenario ay mag pro-progress na agad sa explosive eruption. Kaya lang nag-tagal, so dahil sa bilis ng pangyayari 'yun talaga agad 'yung scenario na kinakaharap natin," Bornas said on Thursday afternoon.

"Kaya lang ngayon nagkaroon ng lull, so we need to evaluate kung ito po ay magiging long-term trend or magkakaroon tayo talaga ng explosive build-up soon or baka naman ito na at kailangan na nating mag relax ng onti," she added.

Bornas said the seeming inactivity was only a "relative lull" as there were still movements taking place below the volcano.

"Meron tayong mga minor explosions at hindi naman nawawala yung steaming or yung hydrovolcanic activities sa bunganga ng bulkan, 'no," Bornas said.

"So meron tayong seeming lull but again inemphasize natin kanina iba yung nangyayari sa ilalim ng bulkan," she added.

As of Thursday, alert level 4 is still raised over the Taal Volcano due to possible imminent hazardous eruption.

The standard operating procedure is to wait for two weeks before the alert level can be lowered.

"Ang importante kasi when you want to stand down sa alert level may definite trend ka na pahupa 'yung volcano. Wala kang definite trend, kunyari nag-increase na naman 'yung earthquake, you cannot just say na tuloy-tuloy lang," PHIVOLCS officer-in-charge Renato Solidum Jr. said.

"Kasi everytime na may paakyat na magma, may threat ka na baka sumabog yung paakyat na magma," he added.

PHIVOLCS on Thursday morning reported an increase in the amount of sulfur dioxide released by the volcano, which indicated the upward movement of magma to the surface.

"May masusukat pa tayo na mataas na sulfur dioxide, meron pa tayong mga earthquakes, may fissure tayo na na-develop, at namaga yung bulkan. So andyan parin yung potential na magkaroon tayo ng explosive eruption. Hind yun nawawala," Bornas said.

Solidum clarified that not all areas within the given 14-kilometer danger zone should evacuate.

"Pag sinabi nating within 14-kilomter radius, hindi literally lahat ng lugar sa loob ng 14-kilometers evacuate mo kung hindi sila ma-apektuhan ng base surge," Solidum said.

In its 5 p.m. bulletin, PHIVOLCS reiterated the total evacuation of the Taal Volcano  Island and high-risk areas. Residents around Taal were also advised to guard against the effects of heavy and prolonged ashfall. —NB, GMA News