The Philippine Institute of Volcanology and Seismology (Phivolcs) on Thursday said the probability of a hazardous explosive eruption of restive Taal Volcano has slowly diminished.
Department of Science and Technology (DOST) Undersecretary and Phivolcs Director Renato Solidum said current assessments conducted by volcano experts showed a 30 percent probability of eruption but maintained that Alert Level 4 remains in effect.
Such probability, he said, is still “very high,” and would expose anybody within or even near high-risk areas within the 14-kilometer radius from the main crater of the volcano in grave danger.
The prediction was first revealed to local government officials in Batangas by volcano experts to give them an idea of what might happen in the next few days, Solidum said.
The official said on January 12, right after the phreatic eruption, which prompted them to place Taal Volcano under Alert Level 4, the probability of hazardous explosive eruption was 10 out of 10.
Today, with the weakening of the volcanic activity, such probability has diminished considerably.
Explaining how Phivolcs came up with such prediction, Maria Antonia Bornas, chief of Phivolcs Volcano Monitoring and Prediction Division, said they weighed in several monitoring parameters.
“We looked at the monitoring parameters that we have and we give these parameters weight. We have experts that provide opinion on what the data is showing, we have historical data and we have deposits. These combined, we give our prediction,” she said.
According to Bornas, Phivolcs started recovering data to calculate the probabilities based on monitoring records on January 17.
Over the past few days, the volcano, one of the world’s smallest yet the country’s second-most active after Mayon Volcano in Albay, was quiet outside, spewing less sulfur dioxide, and causing weaker volcanic earthquakes.
However, this does not mean that hydrovolcanic and magmatic activity is not happening.
Solidum added that the situation and reading of the parameter changes everyday which is why Alert Level 4 remains in effect.
In its Volcano Bulletin issued at 8 a.m. on January 23, Day 11 since the eruption on January 12, Phivolcs said activity in the main crater in the past 24 hours has been characterized by weak to moderate emission of white steam-laden plumes 50 meters to 500 meters high from the main crater that drifted southwest.
Meanwhile, sulfur-dioxide (SO2) emission was measured at an average of 141 tons per day, the third consecutive day that such reduced toxic gas emission was observed.