THE Philippine Institute of Volcanology and Seismology (Phivolcs) on Tuesday, March 9, 2021, elevated the alert status of Taal Volcano to Level 2 because of increasing unrest.
“This means that there is probable magmatic activity that may or may not lead to an eruption,” Phivolcs said.
Phivolcs said evacuation is not yet recommended.
However, the public is reminded that Taal Volcano Island is a permanent danger zone (PDZ). Entry is prohibited, especially in the vicinities of the main crater and the Daang Kastila fissure.
Phivolcs urged local government units (LGU) to continuously assess previously evacuated barangays around Taal Lake for damage and road accessibility.
LGUs were also urged to strengthen preparedness, contingency, and communication measures.
The residents were advised to be always prepared, keep calm and listen to information only from trusted or verified sources.
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.
Phivolcs said Taal Volcano has been exhibiting increased unrest since February 13 based on the frequency of volcanic earthquakes, increased temperature and acidity in the main crater lake, ground deformation and microgravity changes across Taal Caldera.
In the past 24 hours, Phivolcs said the Taal Volcano Network (TVN) recorded 28 volcanic earthquakes, four low frequency volcanic earthquakes (LFVQs) and one hybrid earthquake at shallow depths of less than 1.5 kilometers beneath Taal Volcano Island.
A total of 866 volcanic tremor events and 141 LFVQs have been detected since February 13.
“Overall, seismic activity in the past month indicates increased magmatic and hydrothermal activity at shallow depths beneath TVI,” Phivolcs said.
The agency also recorded a temperature high of 74.6ºC and continuing increase in acidity to pH 1.59 from a pH of 2.79 in January 2020 of the main crater lake.
“Increasing acidity is caused by sustained volcanic gas input into the shallow hydrothermal system that feeds into the lake, signifying degassing of magma intruded at depth during the January 2020 eruption,” Phivolcs said.
There is also an ongoing slight deformation of TVI centered on a pressure source on its southeast sector.
Phivolcs also noted positive microgravity changes across Taal Caldera after the 2020 eruption consistent with density changes caused by magma migration, magma degassing and hydrothermal activity.
Taal Volcano last erupted on January 12, 2020, its abrasive volcanic ash crippling parts of Calabarzon, Central Luzon and Metro Manila. (Third Anne Peralta-Malonzo/SunStar Philippines from PR)