AN "elevated" unrest at Taal Volcano in Batangas province has been observed as 259 volcanic earthquakes, including 236 tremors, were recorded in the past 24 hours, increasing the possibility of eruption, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Wednesday.

Through its Taal Volcano Network (TVN), Phivolcs has monitored a total of 2, 015 volcanic tremors, 734 low-frequency volcanic earthquakes and 18 hybrid earthquake events since Taal became restive on Feb. 13, 2021.

Phivolcs chief Renato Solidum Jr. told The Manila Times that sulfur dioxide gas emission in the previous week has been generally high with a peak of 1, 182 tons on March 21, 2021.

Overall seismic activity release has markedly increased since Tuesday afternoon compared to previous seismic swarms, Solidum said.

He said ground deformation parameters from electronic tilt and data analysis indicated a very slow and steady inflation and expansion of the Taal region since after the January 2020 eruption.

“These parameters may indicate increased magmatic activity at shallow depths beneath the edifice, increasing the possibilities of eruption,” Solidum said.

Phivolcs said Alert Level 2, which means there is an increased unrest, is currently maintained over Taal Volcano “but that unrest has been elevating and is under constant evaluation.”

It reminded the public that at Alert Level 2, sudden steam-driven explosions, volcanic earthquakes and expulsions of volcanic gas, among others, can happen and threaten areas within and around the Taal Volcano Island (TVI).

Solidum said entry into TVI and Taal’s Permanent Danger Zone, especially in the vicinities of the main crater and the Daang Kastila fissure must remain strictly prohibited.

Meanwhile, local government units near the TVI have been advised to continuously assess and strengthen the preparedness of previously evacuated villages around Taal Lake in case of renewed unrest, Phivolcs said.

Also, Phivolcs said civil aviation authorities must advise pilots to avoid flying close to the volcano as airborne ash and ballistic fragments from sudden explosions and wind-remobilized ash may pose hazards to aircraft.