Manila: The level of unrest in Mayon Volcano has increased, particularly at its summit or surface level, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported on Tuesday.

According to Philippines News Agency, Phivolcs Director Teresito Bacolcol highlighted that rockfall events have nearly doubled, from 44 recorded between January 4 and 5 to 85 between January 5 and 6. This increase signals growing instability at the volcano's summit, often linked to magma rising from beneath the surface.

The Phivolcs observed incandescent rockfall from the summit lava dome on Monday night. Incandescent rockfall involves hot material that appears glowing, especially at night, indicating that the rocks originated from the hot portions of the summit lava dome or newly exposed volcanic material. In contrast, an ordinary rockfall occurs when rock fragments collapse or roll from steep parts of the volcano due to gravity or instability, and does not necessarily involve heat from magma.

Bacolcol explained that ordinary rockfalls mainly suggest mechanical or structural instability, while incandescent rockfalls could indicate the presence of heat and pressurized material near the summit, pointing to active magmatic influence. He noted that earlier rockfall events could have included incandescent rockfalls, but these were mostly observed during the day, making it difficult to determine whether they contained hot material. Nighttime rockfall events were clearly observed as incandescent due to their glowing appearance.

Despite Mayon Volcano's seismicity remaining low, the increasing trend in rockfalls and deformation points to elevated unrest. The volcano is currently under Alert Level 2, and entry into the six-kilometer permanent danger zone (PDZ) is strictly prohibited. Bacolcol urged residents inside the PDZ to be prepared to evacuate immediately if the alert level is raised to Alert Level 3. He also advised the public to rely solely on official advisories from Phivolcs and local government units.