Elevated unrest has recurred in Taal Volcano in the past 48 hours and its condition remains unstable, the Philippine Institute of Volcanology and Seismology said Wednesday.
The volcano has been under Alert Level 2 (increased unrest) since March 9.
Phivolcs Director Renato Solidum Jr. earlier said if current unrest persists, this can lead to an eruption.
For the past 24 hours, Phivolcs recorded 355 volcanic earthquakes, including 201 low frequency volcanic quakes, which were caused by movements or eruptions of magma from the volcano.
Activity at the main crater was dominated by the upwelling of hot volcanic fluids in its lake which generated 200-meter tall but weak plumes.
Sulfur dioxide (SO2) emission averaged 3,463 tons/day on May 11, Phivolcs said.
Meanwhile, Mt. Bulusan in Sorsogon province was rocked by 166 volcanic earthquakes on Wednesday, signifying a rising level of volcanic activity for the past three days (May 10-12).
Phivolcs raised the volcano’s status to Alert Level 1 (abnormal) on Tuesday.
Paul Alanis, Phivolcs resident volcanologist in Sorsogon, said the series of volcanic quakes were due to hydrothermal pressure that has been building up in the volcano’s vent.
He explained that hydrothermal activity is caused by water mixing with hot rocks, producing gas pressure and rock movements in the volcano’s vent.
Alanis described the volcano’s abnormality as “localized,” since the quakes generated were not related to magma but hydrothermal pressure detected near the crater.
Historically, Mt. Bulusan has had phreatic eruptions under Alert Level 1.
Phivolcs records indicate that Bulusan’s last eruption was in 2017. In July 2020, volcanologists raised the volcano’s alert status to Level 1 but in October last year, scientists returned the status to “normal.”