Taal Volcano registered a total of 23,576 tons of sulfur dioxide (SO2) emissions on Friday morning, Oct. 15, which is the second-highest after its peak emission of 25,456 tons on Oct. 5, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
Phivolcs noted that Taal Volcano has been emitting "anomalously high" SO2 in the past few weeks.
"SO2 flux this month has averaged 9,872 tons per day as the trend in average flux continues to increase since March 2021," it said in a volcano advisory issued at 6 p.m., Friday.
"Degassing at the Taal Main Crater, in addition, has been noticeably voluminous and generated steam-laden plumes as tall as 3,000 meters above the Taal Volcano Island or TVI," Phivolcs added.
As a result, thick volcanic smog or vog was observed over the Taal Caldera region, which is "expected to drift to the general north to west based on air parcel trajectory forecasts from the PAGASA (Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA)."
Phivolcs also noted that volcanic earthquake activity at Taal resumed on Oct. 11 after a period of lull that began on Sept. 27.
A total of 145 events consisting mostly of weak low-frequency earthquakes and volcanic tremors that are associated with magma and magmatic gas flow have been recorded since seismic activity resumed until 4 p.m., Friday.
Moreover, sudden inflation of the TVI was detected by GPS monitoring in August 2021, consistent with renewed pressurization of the subsurface hydrothermal system due to continuous magmatic degassing, Phivolcs said.
It reminded the public that Taal Volcano remains under Alert Level 2, which means that the current SO2 parameters indicate high levels of magmatic degassing from the main crater that could drive explosive activity.
"At Alert Level 2, sudden steam- or gas-driven explosions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within and around TVI," it pointed out.
The volcano has been under Alert Level 2 since July 23, 2021.
Phivolcs reiterated that entry into the Taal Volcano Island, which is a permanent danger zone, especially the vicinities of the main crater and the Daang Kastila fissure, is strictly prohibited.
Boating on Taal Lake is also be prohibited, it added.
Phivolcs advised the concerned local government units to continuously assess and strengthen the preparedness of previously evacuated barangays around Taal Lake in case of renewed unrest.