Steam plumes and volcanic smog or "vog" produced by the upwelling of hot volcanic fluids have been observed over Taal Volcano in the past 24 hours, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Friday, Aug. 13.

Phivolcs said the activity at Taal's main crater has been dominated by the upwelling of hot volcanic fluids in its lake which generated plumes 2.5 kilometers tall.

Its sulfur dioxide emission has increased to 8,997 tonnes on Aug. 12, from 3,004 tonnes on Aug. 11, resulting in the formation of volcanic smog over the Taal Volcano Island.

In the past 24 hours, Taal also recorded 18 volcanic earthquakes, consisting of seven volcanic tremor events having durations of two to 16 minutes, nine low-frequency volcanic earthquakes, and two hybrid events, including a low-level background tremor that has persisted since July 7.

Phivolcs noted that Taal Volcano will remain at Alert Level 2 due to "decreased unrest." It has been under this status since July 23, 2021.

In the past 24 hours, Taal had 107 volcanic earthquakes, including 100 volcanic tremor events having durations of two 30 minutes, six low-frequency volcanic earthquakes, and one hybrid event, including a low-level background tremor that has persisted since July 7, 2021.

"Based on ground deformation parameters from electronic tilt, continuous GPS and InSAR monitoring, Taal Volcano Island has begun deflating in April 2021 while the Taal region continues to undergo very slow extension since 2020," Phivolcs pointed out.

As Taal Volcano remains under Alert Level 2, it means that 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 the volcano island.

Phivolcs recommended that entry into Taal Volcano Island, Taal’s permanent danger zone, especially the vicinities of the main crater and the Daang Kastila fissure, as well as occupancy and boating on Taal Lake, must be strictly prohibited.