Albay province went on alert after a phreatic eruption was recorded at the Mayon Volcano summit on Sunday afternoon.
According to the Albay Public Safety and Emergency Management Office, the initial incident should not cause any concern at the moment, Albay Gov. Grex Lagman said.
“I have talked with our APSEMO head Dr. Cedric Daep. He reported to me that it’s just white steam. No cause for concern. Same assessment by Phivolcs,” he said.
The Philippine Institute of Volcanology and Seismology earlier said Mayon’s emission “lasted 4 minutes and 9 seconds based on the seismic record.”
The phreatic eruption generated a booming sound, rockfall, pyroclastic density currents, and a 1,200 meter-tall plume that drifted to the southwest.
Mayon Volcano remains at Alert Level 2, PHIVOLCS said.
A phreatic eruption is a steam-driven explosion that happens when magma heats the ground or surface water, according to the United States Geological Survey (USGS).
The intense heat can cause water to boil and flash into steam, which results in an explosion of water, steam, rock and ash. It can also often precede, accompany or follow a more traditional volcanic eruption.
PHIVOLCS Director Teresito Bacolcol said ashfall has not been reported so far.
PHIVOLCS resident volcanologist Dr. Paul Alanis said there is a possibility of ashfall in the towns of Daraga, Albay, Camalig and Guinobatan.
Mayon is currently on Alert Level 2 and this occurrence should be expected, the agency added.