The Philippine Institute of Volcanology and Seismology said on Tuesday that the Mayon volcano in Albay is exhibiting moderate emission of white steam-laden plumes drifting southwest recording one volcanic earthquake in the past 24 hours.

Phivolcs warned the current unrest of the Mayon is driven by shallow magmatic processes that could eventually lead to phreatic eruptions or even precede hazardous magmatic eruptions.

Hence, entry to the six-kilometer-radius Permanent Danger Zone remains strictly prohibited to minimize people's risks from sudden explosions, rockfalls and landslides.

Phivolcs said it is following stand-down procedures, with at least 2 weeks observation period of the volcano parameters before deciding whether to downgrade or upgrade the alert level status of the Mayon.

Should there will be a decreasing trend in the volcano activity, Phivolcs may warrant a lowering of alert level. It noted that this decision will be based on a thorough analysis and recommendation from its 24/7 monitoring division.

Alert Level 2 unrest status prevails in Mayon Volcano. Under these conditions, there are increasing emission rates of baseline sulfur dioxide and swelling of the volcanic edifice.

Sudden pyroclastic flow

Paul Alanis, Phivolcs resident volcanologist in Mayon Volcano Observatory in Legazpi City, cited the lava dome of Mayon Volcano has increased from 40,000 cubic meters in 2019 to 48,000 cubic meters on 10 October, expecting a pyroclastic flow.

"Pyroclastic collapse is possible if it continues to grow. These are the remnants of 2018 when the eruption suddenly halted," Alanis warned.

A pyroclastic flow occurs as part of certain volcanic eruptions described as a dense, fast-moving flow of solidified lava pieces, volcanic ash, and hot gases.

Meanwhile, the Civil Aviation Authority of the Philippines said its 'notice to airmen' will remain in effect until Wednesday should the Phivolcs decide to lower the alert level status of the volcano.