By Ellalyn De Vera-Ruiz
The Philippine Institute of Volcanology and Seismology (Phivolcs) could raise Taal Volcano's alert status to Level 2, amid the continuous detection of high seismic activity, which indicate increasing volcanic unrest.
Taal Volcano (Wow Batangas website / File Photo / MANILA BULLETIN)
Based on Phivolcs' bulletin on Sunday, Taal Volcano has so far manifested 4,857 volcanic earthquakes since it was placed under alert Level 1 on March 28, 2019.
Some of the tremors were felt with intensity ranging from Intensity I (scarcely perceptible) to Intensity III (weak shaking) in Brgy. Banyaga, Agoncillo; Brgy. Calauit, Balete; Sitio Tibag, Brgy. Pira-Piraso, Sitio Tuuran, Brgy. Tabla, and Brgy. Buco, Talisay; and Brgy. Alas-as and Brgy. Pulangbato, San Nicolas, Batangas.
Phivolcs said that the earthquakes were often accompanied by rumbling sounds.
It also found that the precise leveling measurements on Taal Volcano from November 21 to November 29 showed further inflation of the volcano edifice, consistent with the recent results from continuous global positioning system or GPS data. Many volcanoes are known to have inflated before eruptions.
Phivolcs also detected an increase in carbon dioxide emission inside the main crater starting in April 2019. However, there are no significant changes in the water temperature and acidity of the main crater lake.
While volcanic seismicity remains high, Alert Level 1 will be maintained as "hazardous eruption is not imminent," according to Phivolcs.
However, it noted that there is a possibility of magmatic disturbance ongoing under the volcano.
"In the event of further increase in number of volcanic earthquakes, higher concentration of gases, continuous inflation of the volcano’s edifice, increase in water temperature and/or occurrence of widespread bubbling at the lake of the main crater, Taal Volcano’s status will be raised to Alert Level 2," it said.
Phivolcs reminded the public that the main crater should be strictly off-limits because sudden steam explosions can occur and high concentrations of toxic volcanic gases can be released.
The northern portion of the main crater rim, in the vicinity of Daang Kastila Trail, can also become hazardous when steam emission along existing fissures suddenly increases.
Furthermore, the public is reminded that the entire volcano island is a permanent danger zone and permanent settlement is strictly prohibited.
Taal Volcano had a total of 33 historical eruptions and the last major eruption happened on October 3, 1977.