Lava eruption from the summit and lava collapse events characterized Mayon Volcano's eruptive activity in the past 24 hours. Three (3) episodes of volcanic tremor, two of which corresponded to lava fountaining, sixty-four (64) rockfall events and one (1) pyroclastic density current or PDC were recorded by Mayon's seismic monitoring network. Strombolian activity at 10:45 PM and 2:25 AM generated 500 meter- to 200 meter- high lava fountains, respectively, and ash plumes that rose 1,300 meters above the summit. The ash plumes were drifted southwest and ashfall was experienced in barangays of Oas and Guinobatan.
The lava fountains signified an increase in mass eruption rate, as lava was observed to be flowing more voluminously than before, feeding the advancing Miisi lava flow anew and feeding two new lava flows on the Bonga Gully and upper Buyuan watershed. Rockfall events were generated by the collapsing lava front and margins of the advancing lava flow and by shedding from the summit dome onto the Bonga Gully. Currently, the Miisi lava flow has advanced beyond three (3) kilometers from the summit crater well within the Permanent Danger Zone (PDZ). Weak ash clouds were lofted from the rockfall events as well as from the persistent disintegration of lava on the advancing front of the Miisi lava flow before drifting to the southwest. During night time, crater glow with incandescent rock flow along Miisi gully was observed. Sulfur dioxide gas emission was measured at an average of 689 tonnes/day on January 21, 2018. Electronic tilt measurements indicate a sustained swelling or inflation of the edifice since November 2017, consistent with pressurization by magmatic intrusion.
Alert Level 3 remains in effect over Mayon Volcano, which means that it is currently still in a relatively high level of unrest and hazardous eruption is still possible within weeks or even days. The public is strongly advised to be vigilant and desist from entering the six (6) kilometer-radius Permanent Danger Zone (PDZ) and the 7-km Extended Danger Zone (EDZ) on the southern flanks due to the danger of rockfalls, landslides and sudden explosions or dome collapse that may generate hazardous volcanic flows. Increased vigilance against pyroclastic density currents, lahars and sediment-laden streamflows along channels draining the edifice is also advised. Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft. Based on the seasonal wind pattern, ash fall events may most likely occur on the southwest side of the volcano. DOST-PHIVOLCS maintains close monitoring of Mayon Volcano and any new development will be communicated to all concerned stakeholders.
