ReliefWeb

This serves as a notice for raising the alert status of Bulusan Volcano from Alert Level 0 (Normal) to Alert Level 1 (Low-level Unrest).

At 10:37 AM today, a phreatic eruption occurred at the Bulusan Volcano summit that lasted approximately 17 minutes and was recorded by seismic and infrasound monitoring by the Bulusan Volcano Network (BVN). The event was poorly visible through cloud cover over the edifice although a steam-rich grey plume at least 1 kilometer tall was observed from Juban, Sorsogon and was subsequently observed to drift west. Ashfall has been reported in Juban and Casiguran, Sorsogon. Prior to the eruption, the BVN recorded 77 volcanic earthquakes in the past 24-hour observation period. Ground deformation data from continuous GPS monitoring indicate that the Bulusan edifice has been generally inflated since July 2020, while electronic tilt monitoring recorded a sudden but isolated inflation of the southeast lower slopes only since April 2022. These parameters indicate that volcanic processes are underway beneath the edifice that are likely caused by shallow hydrothermal activity.

Alert Level 1 status is now raised over Bulusan Volcano, which means that it is currently in an abnormal condition. Local government units and the public are reminded that entry into the 4-kilometer radius Permanent Danger Zone (PDZ) must be strictly prohibited and that vigilance in the 2-kilometer Extended Danger Zone (EDZ) on the southeast sector must be exercised due to the increased possibilities of sudden and hazardous phreatic eruptions. Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft. Furthermore, people living within valleys and along river/stream channels especially on the southeast, southwest and northwest sector of the edifice should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should phreatic eruption occur. DOST-PHIVOLCS is closely monitoring Bulusan Volcano’s condition and any new development will be communicated to all concerned stakeholders.