The explosion which rocked Taal Volcano yesterday is definitely not unexpected. Since March of last year, the Philippine Volcanology and Seismology (PHILVOCS) already noticed unusual earthquake activity in the Taal island. The agency in fact, raised alert level one in December 2019.
In its advisory, PHILVOCS described it as thus:
“last March 28, 2019, the Taal Volcano seismic network has recorded 4857 volcanic earthquakes as of today (December 1, 2019). Some of these earthquakes 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. Often, these felt earthquakes were accompanied by rumbling sounds. Precise leveling (PL) measurements on Taal Volcano Island from November 21 – 29, 2019 showed further inflation of the volcano edifice, consistent with the recent results from continuous GPS data. An increase in Carbon Dioxide (CO2) emission is also observed inside the Main Crater starting around April of 2019. However, there are no significant changes in the water temperature and acidity of the Main Crater Lake.
Alert Level 1 remains in effect over Taal Volcano. This means that hazardous eruption is not imminent. However, 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.” see link.