Over 100 tremor episodes lasting one to 34 minutes have been detected in Taal Volcano during the 24-hour observation of the Philippine Institute of Volcanology and Seismology (Phivolcs).

In its volcano bulletin issued on Friday, Feb. 26, Phivolcs said only weak steam-laden plumes were emitted by fumarolic (hydrothermal) activity at the vents of the main crater despite the occurrence of 113 tremor episodes.

Temperature highs of 74.6 degrees Celsius and pH of 1.59 were last measured from the main crater lake, respectively, on Feb. 18 and Feb. 12, 2021, Phivolcs added.

"Ground deformation parameters from continuous electronic tilt on volcano island record a slight deflation around the main crater since October 2020, but overall, very slow and steady inflation of the Taal region has been recorded by continuous GPS data after the eruption," it noted.

With these observations, Phivolcs said Taal Volcano remains under Alert Level 1 due to possible sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas that can occur and threaten areas within the Taal Volcano island. 

Phivolcs strongly discouraged entry into the Taal volcano island, which is a permanent danger zone, especially the vicinities of the main crater and the Daang Kastila fissure.

The local government units were also advised to continuously assess previously evacuated barangays around Taal Lake for damages and road accessibilities and to strengthen preparedness, contingency, and communication measures in case of renewed unrest. 

People were asked to continue to observe precautions due to ground displacement across fissures, possible ashfall, and minor earthquakes. 

Phivolcs also recommended civil aviation authorities to advise pilots to avoid flying close to Mt. Kanlaon and Taal Volcano as airborne ash and ballistic fragments from sudden explosions and wind-remobilized ash may pose hazards to aircraft.