The Philippine Institute of Volcanology and Seismology (Phivolcs) has detected a total of 212 earthquakes in Taal Volcano in the past 24 hours - from 8 a.m., March 30 to 8 a.m., March 31.
Of this number, 168 were episodes of volcanic tremor having durations of one to 20 minutes, and 44 were low frequency volcanic earthquakes, based on Phivolcs' volcano bulletin issued on Wednesday, March 31.
Phivolcs said the activity at Taal Volcano's main crater consisted of weak emission of steam-laden plumes rising five meters.
Sulfur dioxide emission from Taal Volcano averaged 1,229 tonnes per day last March 30, slightly up from 1,073 tonnes per day on March 29.
Meanwhile, temperature highs of 71.8 degrees Celsius and pH of 1.59 were last measured from the main crater lake on March 4 and Feb. 12, 2021, respectively.
Phivolcs added that ground deformation parameters continued to indicate a "very slow and steady inflation and expansion of the Taal region after the January 2020 eruption."
"These parameters may indicate increased magmatic activity at shallow depths beneath the edifice," it said.
Phivolcs pointed out that Taal Volcano will remain under Alert Level 2 "but that unrest has been elevating and is under constant evaluation."
Its alert level has been raised from 1 to 2 on 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 (Taal Volcano Island)," it pointed out.
It warned the public from entering the volcano island, which is a permanent danger zone, especially the vicinities of the main crater and Daang Kastila fissure.
Occupancy and boating on Taal Lake should also be strictly prohibited, Phivolcs added.
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 sudden explosions and wind-remobilized ash may pose hazards to aircraft.