MAYON VOLCANO BULLETIN

5 June 2023

10:00 AM

This serves as a notice of alert level raise from Alert Level 1 to Alert Level 2 of Mayon Volcano.

Since the last week of April 2023, daily visual and camera monitoring of the summit crater revealed an increase in rockfall from the Mayon Volcano’s summit lava dome indicating aseismic growth. Rockfall increased in frequency from an average of 5 events/day to 49 events/day from 5:00 AM of 4 June 2023 to 5:00 AM of 5 June 2023. As of 9 May 2023, the lava dome has increased in volume by approximately 83,000 m³ since 03 February 2023 and a total of nearly 164,000 m³ since 20 August 2022. A total of 318 rockfall events have been recorded by the Mayon Volcano Network since 01 April 2023 while 26 volcanic earthquakes have been recorded for the same period. Short-term observations from EDM and electronic tiltmeter monitoring show the upper slopes to be inflating since February 2023. Longer-term ground deformation parameters based on EDM, precise leveling, continuous GPS, and electronic tilt monitoring indicate that Mayon is still inflated, especially on the northwest and southeast, since 2020. Lastly, the highest SO₂ emission measured by campaign Flyspec on 29 April 2023 averaged 576 t/d, and the last measurement on 23 May 2023 averaged 162 t/d. These low-level volcanic earthquakes, ground deformation, and volcanic gas parameters are overshadowed by recent steep increases in rockfall events which may possibly lead to further dome activity.

In view thereof, DOST-PHIVOLCS is raising the Alert Level of Mayon Volcano from Alert Level 1 (abnormal) to Alert Level 2 (increasing unrest). This means that there is current unrest driven by shallow magmatic processes that could eventually lead to phreatic eruptions or even precede hazardous magmatic eruption. The public is strongly advised to be vigilant and desist from entering the six (6) kilometer-radius Permanent Danger Zone (PDZ) to minimize risks from sudden explosions, rockfall and landslides. In case of ash fall events that may affect communities downwind of Mayon’s crater, people should cover their nose and mouth with a damp, clean cloth or dust mask. Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft. DOST-PHIVOLCS maintains close monitoring of Mayon Volcano and any new development will be communicated to all concerned stakeholders.

DOST-PHIVOLCS