ReliefWeb

I. SITUATION OVERVIEW

A. Chronological of Events and Eruption Notifications from 13 to 27 January 2018 (TAB A)

B. Current Situation

28 January 2018

Between 6:22 PM yesterday to 1:40 AM this morning, two (2) episodes of sporadic lava fountaining from the summit crater lasting 23 minutes and 55 minutes occurred. The events fed lava flows on the Mi-isi and conga Gullies, sprayed near-vent lava spatter, and fed rockfall on the summit area. In between lava fountaining episodes, lava effusion continued to feed lava flows on the Bonga and Miisi Gullies. Heavy rainfall throughout the day generated sediment-laden stream flows in channels draining the volcano edifice.

A total of four (4) volcanic earthquakes, seven (7) tremor events, two (2) of which correspond to the lava fountaining events, twenty-three (23) 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 3 and 1.8 km, respectively, from the summit crater_ Sulfur dioxide gas emission was measured at an average of 1,916 tonnes/day on 25 January 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 magmatic intrusion.