PHIVOLCS TAAL Volcano Bulletin 20 July 2021 8:00 AM

In the past 24-hour period, the Taal Volcano Network recorded thirty-six (36) volcanic earthquakes, including thirteen (13) volcanic tremor events having durations of one (1) to ten (10) minutes, twenty (20) low-frequency volcanic earthquake, three (3) hybrid events and low-level background tremor that has persisted since 07 July 2021. Two of the tremor events occurred at 10:18 AM and 10:38 AM were felt at Intensity I in Pira-piraso, Taal Volcano Island, the earlier event reportedly accompanied by a rumbling sound. High levels of volcanic sulfur dioxide or SO2 gas emissions and steam-rich plumes that rose one thousand two hundred (1200) meters before drifting east and northeast were generated from the Taal Main Crater. Sulfur dioxide (SO2) emission averaged 3,780 tonnes/day on 19 July 2021. Based on ground deformation parameters from electronic tilt, continuous GPS and InSAR monitoring, Taal Volcano Island has begun deflating in April 2021 while the Taal region continues to undergo very slow extension since 2020.

Alert Level 3 (Magmatic Unrest) now prevails over Taal Volcano. At Alert Level 3, magma extruding from the Main Crater could drive explosive eruption. The public is reminded that the entire Taal Volcano Island is a Permanent Danger Zone (PDZ), and entry into the island as well as into the high-risk barangays of Agoncillo and Laurel must be prohibited due to the hazards of pyroclastic density currents and volcanic tsunami should strong eruptions occur. All activities on Taal Lake should not be allowed at this time. Communities around the Taal Lake shores are advised to remain vigilant, take precautionary measures against possible airborne ash and vog and calmly prepare for possible evacuation should unrest intensify. Civil aviation authorities must advise pilots to avoid flying over Taal Volcano Island as airborne ash and ballistic fragments from sudden explosions and pyroclastic density currents such as base surges may pose hazards to aircraft. DOST-PHIVOLCS maintains its close monitoring of Taal Volcano and any new development will be communicated to all concerned stakeholders.