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Taal emits less sulfur dioxide; low-frequency earthquakes continue

The sulfur dioxide emission of Taal Volcano has further dwindled and its seismic activity appears to be relatively calming down as of Thursday morning, but the Philippine Institute of Volcanology and Seismology (PHIVOLCS) is still not discounting the possibility of an imminent hazardous eruption.

According to its 8 a.m. bulletin, the sulfur dioxide released by Taal Volcano further dropped to an average of 141 tonnes per day—lower than Wednesday's average of 153 tonnes per day.

The latest figure is significantly lower compared to the average of 5,299 tonnes daily, which was recorded on January 13, a day after Taal Volcano awakened.

Sulfur dioxide emission is an indicator of the upward movement of magma to the surface, according to PHIVOLCS.

Meanwhile, only six volcanic earthquakes were recorded by the Philippine Seismic Network (PSN) from 5 a.m. on Wednesday to 5 a.m. on Thursday.

This brings to 731 the total number of plotted volcanic earthquakes since Taal Volcano's initial eruption on January 12.

On the other hand, the Taal Volcano Network, which can record small seismic activities, detected 467 volcanic earthquakes in the past 24 hours.

Eight of these were low-frequency earthquakes which, according to the United States Geological Survey, are "caused by cracks resonating as magma and gases move toward the surface."

"They are often seen prior to volcanic eruptions, but their occurrence is also part of the normal background seismicity at some volcanoes and their occurrence does not necessarily indicate that an eruption is imminent," the USGS said.

PHIVOLCS warned that a hazardous eruption is still possible within hours to days.

The institute's Volcano Monitoring and Eruption Prediction Division chief Mariton Bornas stressed that magma has already risen near the surface.

"Ngayon ay mababa po ang parameters pero nag-aalala po tayo kung anong mangyayari doon sa magma na nakaakyat na po at naghihintay o naka-abang sa ilalim ng bulkan," she said in an interview on GMA News' Unang Hirit.

In the past 24 hours, Taal Volcano exhibited "weak to moderate emission" of white steam-laden plumes, 50 to 500 meters high that drifted to the southwest of the main crater.

PHIVOLCS reiterated that Taal Volcano Island, the areas within the 14-kilometer radius from the main crater, and areas along the Pansipit River Valley must be evacuated due to hazards such as base surge and volcanic tsunami.

Other communities around the volcano must also prepare against the effects of heavy and prolonged ashfall.

The airspace around Taal Volcano remains unsafe to aircraft due to airborne ash and ballistic fragments from the eruption column. — RSJ, GMA News