This serves as a notice for the raising of Mayon Volcano's status from Alert Level 1 (abnormal) to Alert Level 2 (increasing unrest).
Phivolcs raised the alert to level 2 in the early hours of Sunday, which means that the current activity is "probably of magmatic origin, which could lead to more phreatic eruptions or eventually to hazardous magmatic eruptions".
The Philippines has raised the alert level at the volcano in the northern province of Albay after it spewed grayish steam and ash plume three times in less than24 hours.
"The public is strongly advised to be vigilant and desist from entering the six kilometre (3.7 mile) radius Permanent Danger Zone to minimise risks from sudden explosions, rockfall and landslides", Phivolcs said in a statement today.
It was followed by rumbling sounds and a faint glow in the crater, Phivolcs said.
In an advisory, Bichara reiterated the evacuation of residents inside and within the periphery of the 6-km PDZ.
A second ash eruption was also recorded before noon on Sunday. It last erupted in 2014.
This also suggests there is no imminent major eruption, but the Provincial Disaster Risk Reduction Management Council said it had ordered the evacuation of residents for the safety of their health due to expected ashfall. It was at its most deadly in February 1841, when 1200 people were killed and lava buried a town.
"We have not reached the critical level", he said in a radio interview.
In a bulletin issued 8 pm on Sunday, January 14, Phivolcs said there have been 3 phreatic or steam-driven eruptions and 158 rockfall events between 4:21 pm of Saturday, January 13, and 7:25 pm of Sunday.
Experts say it has been displaying abnormal behaviour since late previous year.
"In case of ash fall events, which are most likely to affect communities on the western and southwestern flanks downwind of Mayon's crater, people should cover their nose and mouth with damp, clean cloth or dust mask", PHIVOLCS said.
The volcano has been displaying abnormal behavior since late a year ago.