Science and Technology Undersecretary Renato Solidum Jr. on Saturday, June 5, said Taal Volcano in Batangas remains under Alert Level 2 as "increased unrest" continues to be observed by the Philippine Institute of Volcanology and Seismology (Phivolcs).
While Phivolcs has not detected earthquakes in the past couple of days, Solidum said Taal Volcano continues to show various parameters, such as volcanic gas upwelling in its main crater, high sulfur dioxide emission, background tremor, and ground deformation.
Solidum, who is also the OIC of Phivolcs, noted that the allowed activities in permanent danger zones, in this case, the whole Taal Volcano Island, will have to be decided by Regional and Provincial Disaster Risk Reduction and Management Councils, "when the condition gets back to Alert Level 0 or Normal."
"Taal Volcano is not in that state yet," he pointed out in a statement on Saturday.
"The alert level of the volcano is based on various parameters being monitored, not only earthquakes but gas concentration measurements, temperature and chemical parameters of the lake and ground deformation, steaming and other observations," he explained.
In its bulletin on Saturday, Phivolcs said Taal's main crater was dominated by the upwelling of hot volcanic fluids in its lake, which generated plumes about 700 meters high.
Moreover, sulfur dioxide emission averaged 1,690 tonnes per day as recorded on Friday, June 4, and temperature highs of 71.8°C and pH of 1.59 were last measured from the main crater lake on March 4 and Feb. 12, 2021, respectively.
"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 has been very slowly and steadily inflating and expanding at diminishing rates since after the eruption in 2020," Phivolcs said.
"These parameters indicate a decline in magmatic activity at shallow depths beneath the edifice," it added.
Solidum stressed that Alert Level 2 stays over Taal Volcano as "sudden steam-driven or phreatic eruption can occur and entry to Taal Volcano Island is prohibited."