Taal Volcano spews 2,800-meter plume from minor phreatomagmatic eruption

MANILA, Philippines – A four-minute minor phreatomagmatic eruption, or an eruption involving both water and magma, occurred at Taal Volcano in Batangas at 5:58 am on Tuesday, December 3.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said in an advisory at 9:30 am that the minor eruption “was likely driven by sudden contact of water with a small batch of shallow magma.”

That magma has been in place beneath the volcano’s main crater and has been “degassing sustained levels of SO2 (sulfur dioxide) for the past three years.”

The minor eruption generated a dark plume that rose 2,800 meters or 2.8 kilometers above Taal Volcano Island.

Phivolcs said “traces of ash” were reported in Barangay Poblacion in the town of Agoncillo and Barangay Buso-buso in the town of Laurel, both in the province of Batangas.

The agency noted that Taal has shown “increased volcanic gas emissions and localized ground deformation for the past month, although volcanic earthquakes have been at low levels.”

Last Saturday, November 30, Taal’s SO2 emission averaged 7,216 tons per day, which Phivolcs said was higher than the monthly average of 5,283 tons per day.

“Degassing of high concentrations of volcanic SO2 continues to pose the threat of potential long-term health impacts…. Local government units are advised to continuously monitor and assess preparedness of their communities and undertake appropriate response measures to mitigate hazards,” Phivolcs said.

In terms of ground deformation, portions of the volcano have been inflated or swollen since September, but generally, “long-term deflation of the Taal Caldera region has persisted since 2020.”

“The background levels of volcanic earthquake activity and localized ground deformation detected at Taal indicate that unrest is unlikely to progress into a major magmatic eruption at this time,” Phivolcs said.

Taal has been under Alert Level 1 or “in abnormal condition” since July 11, 2022.

Under Alert Level 1, these are possible:

• sudden steam-driven or phreatic eruptions and minor phreatomagmatic eruptions
• volcanic earthquakes
• minor ashfall
• lethal accumulations or expulsions of volcanic gas

“Should phreatomagmatic activity at Taal persist or intensify, then the alert level may be raised to Alert Level 2,” Phivolcs said on Tuesday.

Entry into Taal Volcano Island, a permanent danger zone, should still be prohibited. – Rappler.com