On January 26, 2018, the total number of people evacuated around erupting Mayon volcano reached 81 618, according to data provided by the Department of Social Welfare and Development (DSWD). Alert Level 4 remains in effect. Authorities are strongly advising the public to be vigilant and desist from entering the 8 km (5 miles) wide danger zone, and to be additionally vigilant against pyroclastic density currents, lahars and sediment-laden streamflows along channels draining the edifice.
There are 22 827 families or 88 886 persons in 56 barangays in Albay Province affected by the phreatomagmatic eruption of Mount Mayon, DSWD said.
A total of 18 365 families of 69 672 persons are taking temporary shelter in 69 evacuation centers while 2 822 families or 11 946 persons are staying with relatives in Camalig, Daraga, Malilipot, and Santo Domingo, bringing the total number to 81 618.
Between 22:11 UTC, January 24 and 18:31 UTC, January 25, Mayon Volcano Observatory registered 7 episodes of intense but sporadic lava fountaining from the summit lasting 26 - 57 minutes.
The lava fountains reached 150 to 500 m (500 - 1 640 feet) high and generated ash plumes that reached 500 m to 3 km (up to 1.8 miles) above the crater. The events fed lava flows on the Mi-isi and Bonga Gullies, sprayed near-vent lava spatter, and fed incandescent rockfall on the summit area.
Pyroclastic density currents or PDCs on gullies heading the Mi-isi, Lidong/Basud, and Buyuan Channels were also observed. The runout of PDCs on the Buyuan Channel is now exceeding 5 km (3.1 miles) from the summit crater.
Mayon's seismic monitoring network registered 15 volcanic earthquakes, 19 tremor events (of which 7 correspond to the lava fountaining events), one episode of pyroclastic density current or PDC generation from lava collapse, and numerous rockfall events. Rockfall events were generated by the collapsing lava front and margins of the advancing lava flow on the Mi-isi and Bonga Gullies. Currently, the Mi-isi and Buyuan lava flows have maintained their advance to 3 km (1.8 miles) and one 1 km (0.62 miles), respectively, from the summit crater.
Sulfur dioxide gas emission was measured at an average of 1916 tonnes/day on January 25, 2018. Electronic tilt and continuous GPS measurements indicate a sustained swelling or inflation of the edifice since November and October 2017, consistent with pressurization by the magmatic intrusion.
Alert Level 4 remains in effect over Mayon Volcano, PHIVOLCS said, strongly advising the public to be vigilant and desist from entering the 8 km (5 miles) wide danger zone, and to be additionally vigilant against pyroclastic density currents, lahars and sediment-laden streamflows along channels draining the edifice.
Featured image: Mayon volcano on January 25, 2018. Credit: PHIVOLCS