|PUBLIC ADVISORY: Notice of raising Mayon Volcano’s status from Alert Level 3 to Alert Level 4 as of January 22, 2018.|
PHIVOLCS: MAYON VOLCANO BULLETIN 27 January 2018 10:30 A.M.PHIVOLCS has raised the alert level to Alert Level 4 in effect over Mayon Volcano. The public is strongly advised to be vigilant and desist from entering the eight (8) kilometer-radius danger zone, and to be additionally vigilant against pyroclastic density currents, lahars and sediment-laden stream flows along channels draining the edifice.
SUMMARY as of 27 January 2018 10:30 AM
Heavy rains over the Province of Albay brought about by the tail-end of a cold front have increased the dangers of syn-eruption lahars on major channels draining the Mayon Volcano edifice that have been deposited with thick pyroclastic density current or PDC material and ashfall. The total volume of PDC deposits so far deposited on the watershed areas, mostly on the Buyuan and Miisi channel watershed, is approximately 9 million cubic meters, excluding unverified deposits on the northern flank. The total volume of ashfall on the western sector is roughly 1.5 million cubic meters. These deposits can be remobilized by rainwater and generate lahars by themselves and or by incorporating existing erodible material on channel banks.
PHIVOLCS therefore warns of potential lahars and sediment-laden streamflows on all river channels draining the slopes of Mayon Volcano especially the Buyuan, Miisi, Mabinit, Basud, San Vicente, Buang, Quirangay and Masarawag-Maninila that may be generated by heavy rainfalls brought about by the cold-front. Communities and local government units beside these river systems are advised to be additionally vigilant and to move residents to high ground when heavy rains occur. Alert Level 4 remains in effect over Mayon Volcano and DOST-PHIVOLCS maintains its close monitoring of Mayon Volcano and any new development will be communicated to all concerned stakeholders.
SUMMARY as of 27 January 2018 8:00 AM
Between 06:26 AM to 01:40 PM yesterday, three (3) episodes of sporadic lava fountaining from the summit crater lasting twenty-four (24) minutes to forty (40) minutes occurred. The lava fountains generated ash plumes that reached 3 kilometers above the crater. The events fed lava flows on the Mi-isi and Bonga Gullies, sprayed near-vent lava spatter, and fed rockfall on the summit area. Only one (1) pyroclastic density current or PDC on the Miisi Gully was observed. Lava fountaining episodes transitioned into aseismic lava effusion in the early evening, feeding incandescent lava flows on the Bonga and Miisi Gullies, the former of which advanced significantly downslope.
A total of ten (10) volcanic earthquakes, twenty-one (21) tremor events, three (3) of which correspond to the lava fountaining events, one (1) PDC from lava collapse, and twenty-one (21) rockfall events were recorded by Mayon's seismic monitoring network. Rockfall events were generated by the collapsing lava front and margins of the advancing lava flow on the Bonga and Miisi Gullies. Currently, the Miisi and Bonga lava flows have maintained their advance to three (3) and 1.8 kilometers, respectively, from the summit crater. Sulfur dioxide gas emission was measured at an average of 1,916 tonnes/day on 25 January 2018. Source