Sulfur dioxide (SO2) emission from Taal Volcano in the province of Batangas spiked to a new all-time high on Tuesday, October 5.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said in an advisory that it recorded SO2 emission of 25,456 tons per day on Tuesday.

The previous all-time high was 22,628 tons per day last July 4.

SO2 is a major gas component of magma. A high level of SO2 indicates magma is relatively nearer a volcano’s surface.

“Current SO2 parameters indicate high levels of magmatic degassing from the main crater that could drive explosive activity,” Phivolcs warned.

The agency also said SO2 emission has averaged 8,854 tons per day since September 27, “from which time the volcano has fallen seismically quiet,” with zero volcanic earthquakes recorded.

In addition, state volcanologists observed that the “visibly moderate to strong” degassing or emission of gas from Taal’s main crater in the recent period “generated steam-laden plumes as tall as 3,000 meters” or 3 kilometers above Taal Volcano Island.

The island itself saw “sudden inflation” or swelling in August, which Phivolcs said could also be a result of the “continuous magmatic degassing.”

Taal Volcano has been under Alert Level 2 since July 23, downgraded to that level after more than three weeks at Alert Level 3. The Alert Level 3 declaration had been triggered by a phreatomagmatic eruption on July 1.

Phivolcs has been reiterating in its daily bulletins that the following could occur under Alert Level 2:

• sudden steam- or gas-driven explosions
• volcanic earthquakes
• minor ashfall
• lethal accumulations or expulsions of volcanic gas

The agency stressed that Taal Volcano Island and Taal Lake must remain off-limits.

“Local government officials are advised to continuously assess and strengthen the preparedness of previously evacuated barangays around Taal Lake in case of renewed unrest,” added Phivolcs. – Rappler.com