Phivolcs lowers Bulusan Volcano alert level to 0

The Philippine Institute of Volcanology and Seismology (Phivolcs) has lowered the alert level for Bulusan Volcano from Alert Level 1 to Alert Level 0, indicating a return to normal conditions.

Bulusan Volcano had been under Alert Level 1, signifying low-level unrest, since October 25, 2023.

Phivolcs based the downgrade on a noticeable decrease in volcanic earthquakes and sulfur dioxide emissions.

Volcanic earthquakes have declined to baseline levels of 0-5 tremors a day since the third week of August 2024.

Reduced tectonic stresses from the 6.6-magnitude earthquake on August 18, 2020, near the Masbate segment of the Philippine Fault Zone may have led to the decrease in volcanic earthquakes.

Sulfur dioxide emission from its summit vents has been low at an average of 76 tons per day.

Most monitored springs in the volcano have also recorded decreases in acidity, temperature, and diffuse carbon dioxide, indicating no input from deep magma sources.

Despite the return to normal, the public is warned to avoid the permanent danger zone within a four-kilometer radius of the summit due to the lingering risk of sudden steam-driven eruptions, rockfalls, and landslides.

The public is also advised to stay vigilant for potential lahars, especially during periods of heavy rainfall.