The Philippine Institute of Volcanology and Seismology (Phivolcs) has issued a lahar advisory for Mayon Volcano on Thursday, as Tropical Storm Dante, Severe Tropical Storm Emong, and the southwest monsoon (habagat) are expected to bring heavy rains to the Bicol Region.
Phivolcs warned that the anticipated rainfall could generate volcanic sediment flows, or lahars, as well as muddy stream flows or runoff in rivers and drainage areas surrounding Mayon Volcano. The agency urged increased vigilance and readiness among communities in pre-determined zones at risk of lahar and related hazards.
“Heavy to torrential rainfall can generate post-eruption lahars on major channels draining Mayon Volcano by incorporating loose material from remnant pyroclastic density current (PDC) deposits of the 2018 and 2023 Mayon eruptions,” the advisory stated.
Phivolcs noted that the bulk of erodible PDC deposits occupies the watershed areas of the Miisi, Mabinit, Buyuan, and Basud Channels. Additionally, older and erodible eruption deposits on the eastern and western slopes of the volcano can be remobilized as non-eruption lahars due to erosion of banks and channel beds.
“Potential lahars and sediment-laden streamflows may occur along the Miisi, Binaan, Anoling, Quirangay, Maninila, Masarawag, Muladbucad, Nasisi, Mabinit, Matanag, Basud, and Bulawan Channels in Albay Province,” the advisory added.
Phivolcs called on communities and local government units in at-risk areas to continuously monitor rainfall conditions and take pre-emptive response measures to ensure their safety.
