The Philippine Institute of Volcanology and Seismology (Phivolcs) has detected a seismic steaming in Taal Volcano that began at around 11 p.m., Thursday, May 20.

As of 8 a.m., Friday, May 21, Phivolcs said the restive volcano in Batangas is "presently generating a voluminous steam plume two kilometers high and drifting southwest."

In the past 24 hours, Taal Volcano also had 10 earthquakes, including two low-frequency earthquakes and eight tremor events having durations of eight to 37 minutes, and low-level background tremor that has persisted since April 8.

Its sulfur dioxide (SO2) emission remains high with an average of 3,051 tonnes per day as reported on May 20.

Meanwhile, temperature highs of 71.8°C and pH of 1.59 were last measured from the main crater lake on March 4, 2021 and Feb. 12, 2021, respectively.

"Ground deformation parameters from electronic tilt, continuous GPS and InSAR monitoring continue to record a very slow and steady inflation and expansion of the Taal region that began after the January 2020 eruption," Phivolcs said.

These parameters continue to indicate a persistent magmatic activity at shallow depths beneath the Taal Volcano.

As it continues to show signs of elevated unrest, Taal Volcano's status remains under Alert Level 2.

The restive volcano in Batangas has been under Alert Level 2 since March 9, 2021.

"Sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within and around TVI," Phivolcs pointed out.

It reiterated that entry into the volcano island, which is a permanent danger zone, especially the vicinities of the main crater and Daang Kastila fissure, is strictly prohibited.

Occupancy and boating on Taal Lake should also be strictly prohibited, Phivolcs said.

Local government units were advised to continuously assess and strengthen the preparedness of previously evacuated barangays around Taal Lake in case of renewed unrest.

Civil aviation authorities were also asked to advise pilots to avoid flying close to the volcano as airborne ash and ballistic fragments from explosions and wind-remobilized ash may pose hazards to aircraft.