Heavy rainfall raises concerns of lahar in Mayon Volcano

MANILA, Philippines — The Philippine Institute of Volcanology and Seismology (Phivolcs) on Saturday issued a warning about the potential risks posed by heavy rainfall in the vicinity of Mayon Volcano.

In its advisory issued on Saturday at 8 a.m., Phivolcs said that "heavy rainfall could generate channel-confined lahars and sediment-laden streamflows in channels where pyroclastic density current deposits were emplaced."

Aside from the risk of lahars, state volcanologists also cited the dangers of other volcanic hazards such as rockfalls. 

According to Phivolcs, there is a continuing slow effusion of lava from Mayon Volcano's summit crater. Lava flows have extended approximately 2.8 kilometers and 1.4 kilometers along Mi-isi and Bonga gullies, respectively.

Lava collapse was along documented along Basud gully up to 4 kilometers from the crater.

Monitoring reports from 5:00 a.m. of July 14 to 5:00 a.m. of July 15 indicated ongoing unrest. These include five pyroclastic density currents resulting from dome-collapse, 362 rockfall events, 39 volcanic earthquakes, and an average sulfur dioxide emission of 2,132 metric tons.

Phivolcs advised that the six-kilometer radius Permanent Danger Zone around the volcano should remain evacuated as a precautionary measure.

Mayon Volcano remains under Alert Level 3, signifying the possibility of a hazardous eruption occurring within weeks or even days, according to Phivolcs.