Powerful eruption at Mayon volcano, heavy ashfall and zero visibility, Alert Level 4

A powerful eruption took place at Mayon volcano, Philippines around 04:45 UTC on Monday, January 22, 2018 (12:45 local time), producing a column of ash that rose up to 7.6 km (25 000 feet) above sea level. At 05:10 UTC, the Tokyo VAAC reported ash cloud up to 12.5 km (41 000 feet) a.s.l. and corrected it within 30 minutes. Increased activity at the volcano forced authorities to raise the Alert Level from 3 to 4 (hazardous eruption imminent). The scale goes up to 5.

Heavy ashfall was reported in communities around the volcano and as far as Ligao City, some 35 km (21.7 miles) from Legazpi City. Albay Governor said zero visibility has been reported in parts of Guinobatan, Ligao, and Camalig after the major ash eruption, advising everyone to wear their face masks and to stay indoors, especially those in the 3^rd district of Albay.

Classes in all public and private schools across the entire province have been suspended.

Volcanologist Ed Laguerta said the eruption lasted for some 8 minutes and generated pyroclastic flows towards Camalig and Guinobatan towns southwest of the volcano.

"The volcano in Albay Province has been exhibiting increased seismic unrest, lava fountaining and summit explosions," PHIVOLCS said 05:00 UTC (13:00 local time), January 22. "In view thereof, DOST-PHIVOLCS is raising the Alert Level of Mayon volcano from Alert 3 (increased tendency to hazardous eruption) to Alert Level 4 (hazardous eruption imminent)."

Because of this, the Danger Zone is extended to 8 km (5 miles) from the summit vent.

The public is strongly advised to be vigilant and desist from entering this danger zone. Civil aviation authorities must also advise pilots from flying close to the volcano's summit as ash from eruptions can be hazardous to aircraft, the agency added.

PHIVOLCS Director Renato Solidum reminded the public not to panic. "The public is reminded to observe the danger zone — not to panic, but in essence just be ready. Prepare either gas masks, handkerchiefs or clothes to prevent inhalation of fine ash," he told CNN Philippines.

He warned of two possible scenarios: continuous lava eruptions, or a more dangerous pyroclastic flow.

As a long-term solution, residents should start settling more than 6 km away from Mayon, so they won't have to evacuate frequently, he said.

On Sunday, January 21, lava fountaining reached a height of about 500 m (1 640 feet) above the crater and ashfall was reported in Oas and Guinobatan, Albay:

Lava fountaining on Mayon volcano - January 21, 2018. Credit: PHIVOLCS

Lava fountaining on Mayon volcano - January 21, 2018. Credit: PHIVOLCS

Geological summary

Beautifully symmetrical Mayon volcano, which rises to 2 462 m (8 077 feet) above the Albay Gulf, is the Philippines' most active volcano. The structurally simple volcano has steep upper slopes averaging 35-40 degrees that are capped by a small summit crater. Historical eruptions at this basaltic-andesitic volcano date back to 1616 and range from strombolian to basaltic plinian, with cyclical activity beginning with basaltic eruptions, followed by longer term andesitic lava flows.

Eruptions occur predominately from the central conduit and have also produced lava flows that travel far down the flanks. Pyroclastic flows and mudflows have commonly swept down many of the approximately 40 ravines that radiate from the summit and have often devastated populated lowland areas.

Mayon's most violent eruption, in 1814, killed more than 1200 people and devastated several towns. (GVP)

Featured image: Mayon volcano, Philippines on January 22, 2018. Credit: Albay Governor Francis C. Bichara