MANILA- Phivolcs said Friday the Taal Volcano in Batangas continued to show volcanic activity underground despite weaker explosions on its surface.
This is why the agency is hesitant to categorically say if they were considering lowering the alert level from 4 to 3. The current alert level, the second highest in a 5-tier alert system, warns of a possible major eruption in the coming hours or days.
“Sa nakalipas na 24 oras ang activity ng Bulkang Taal ay patuloy na mahina na pagbuga ng aso na mayroong mga kasama paminsan-minsan na maliliit na explosion sa loob ng main crater na nagsaboy ng aso o abo,” Phivolcs Volcano Monitoring and Eruption Prediction Division chief Mariton Bornas said during a press conference on Friday.
(In the last 24 hours, the activity of Taal Volcano includes weak emission of volcanic gases with infrequent weak explosions of ash inside its main crater.)
Bornas said they also observed that some of the existing fissures or cracks in the towns of Lemery, Agoncillo, Talisay and San Nicolas were observed to have widened by a few centimeters.
“There is also a new fissure or crack in the northern (slope) of Taal Volcano,” she said.
Bornas said it was normal to see fissures on volcano island during eruptive activity.
She said data from satellites and GPS showed that the Taal caldera, which includes the Taal Lake area, was “deforming” because of the movement of magma underneath.
“We also have continuous earthquakes,” she added.
Since Jan. 12, Phivolcs has detected 634 volcanic earthquakes. Of this number, 174 ranged from magnitude 1.2 to 4.1 and were felt at Intensities 1 to 4, strong compared to usual volcanic quakes, according to Bornas.
“The danger is still there. There is always a possibility (for an explosive eruption),” she said, adding that anything could happen now that the volcano’s crater is open following the steam-driven explosions on Sunday.
Alert level 4 was raised at the Taal Volcano on Sunday after Phivolcs observed ash columns and phreatic or steam-blast eruptions. This also meant that an explosive eruption may be expected in just hours or days.
Bornas said they were not able to get a sulfur dioxide emission reading, which could help determine if there was rising magma, because their instrument was covered in ash following Sunday's eruption.
She said they already sent personnel to address the problem.
Phivolcs earlier said it would take at least 2 weeks to assess whether the volcanic activity was declining so they could lower the alert level. However, she said they would still need to check if there was magma movement underground.
She declined to comment on questions about evacuation in places outside the identified high-risk areas, saying it was up to local government units to announce if it is safe.
Bornas said that since alert level 4 was still up, people should not stay on volcano island and high-risk areas within a 14-kilometer radius of Taal Volcano’s main crater.