THE Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday said rains from tropical cyclones “Dante” and “Emong” and the southwest monsoon could trigger lahar flows from Mayon Volcano in Albay.
Citing information from the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), Phivolcs said the weather systems “are expected to bring heavy to torrential rains over the Bicol Region.”
“These rains could generate volcanic sediment flows or lahars, muddy stream flows or muddy run-off in rivers and drainage areas on Mayon Volcano,” the agency said in an advisory.
Phivolcs said it “strongly recommends increased vigilance and readiness of communities in pre-determined zones 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 deposits (PDC) of the 2018 and 2023 Mayon eruptions,” it said.
Phivolcs said the bulk of “erodible PDC deposits” are in the watershed areas of the Miisi, Mabinit, Buyuan and Basud channels.
“In addition, older and erodible eruption deposits that occupy the watershed areas on the eastern and western slopes of the edifice and can be remobilized as non-eruption lahars by erosion of banks and channel beds,” it also said.
It said the lahar flows can threaten communities downstream of these channels with “inundation, burial and wash away.”
It added that “potential” lahar and sediment-laden stream flows may occur along the Miisi, Binaan, Anoling, Quirangay, Maninila, Masarawag, Muladbucad, Nasisi, Mabinit, Matanag, Basud and Bulawan channels in Albay.
Phivolcs advised communities and local government units in these areas “to continually monitor the rainfall conditions and take pre-emptive response measures for their safety.”
