PHREATIC EXPLOSION. Ash emerges from the crater of the Taal Volcano on January 12, 2020. Image from Phivolcs

MANILA, Philippines (UPDATED) – The Taal Volcano in Batangas spewed an ash column one kilometer high on Sunday afternoon, January 12, triggering the raising of its status to Alert Level 2 and then Alert Level 3.

The Philippine Institute of Volcanology and Seismology (Phivolcs) first raised Alert Level 2, which means increasing unrest, at 2:30 pm on Sunday.

This was due to a phreatic explosion, or a steam-driven episode that occurs when water beneath the ground or on the surface is heated by magma, lava, hot rocks, or new volcanic deposits.

This was followed by Alert Level 3 at 4 pm, which means magmatic unrest.

Phivolcs said in its 4 pm bulletin that the Taal Volcano's main crater "has escalated its eruptive activity, generating an eruption plume one kilometer high, accompanied by volcanic tremor and felt earthquakes."

"This means that there is magmatic intrusion that is likely driving the current activity," said Phivolcs.

"Ashfall is currently being showered on the southwest sector of Taal," added the agency.

Phivolcs strongly recommended that Taal Volcano Island and the high-risk barangays of Agoncillo and Laurel in Batangas be evacuated, citing "possible hazards of pyroclastic density currents and volcanic tsunami."

It also noted that the entire Taal Volcano Island is a Permanent Danger Zone, and permanent settlement is strongly not recommended.

"In addition, communities around the Taal Lake shore are advised to take precautionary measures and be vigilant of possible lakewater disturbances related to the ongoing unrest," said Phivolcs. – Rappler.com