The Philippine Institute of Volcanology and Seismology (Phivolcs) has detected increased seismicity at Taal Volcano in Batangas, as over 200 low-frequency earthquakes and tremor events were recorded during its 24-hour monitoring period.
In a volcano bulletin issued on Tuesday, June 15, Phivolcs said a total of 221 volcanic earthquakes were logged in the past 24 hours.
Twenty-nine of these were low-frequency volcanic earthquakes and 192 were tremor events with durations of one to 135 minutes, including a low-level background tremor that has persisted since April 8, 2021.
Phivolcs said the activity at the Taal’s main crater was dominated by the upwelling of hot volcanic fluids in its Lake, which generated 1.5-kilometer high plumes.
Sulfur dioxide (SO2) emission also remains high as it averaged 5,837 tonnes per day on Monday, June 14.
"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 said.
It pointed out that these parameters indicate that magmatic unrest continues to occur at shallow depths beneath the edifice.
Phivolcs said Taal Volcano's status will remain under Alert Level 2 due to "increased unrest."
Under Alert Level 2, Phivolcs said that there is a possibility of 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 Taal Volcano Island.
The restive volcano in Batangas has been under Alert Level 2 since March 9, 2021.
Phivolcs 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.