Saturday's eruption unleashed ash, rocks and sulfuric odor, and was followed by rumbling sounds and a faint glow in the crater, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
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 Philippines raised the alert at its restive Mayon volcano by one notch early on Sunday, citing signs of rising magma that could lead to hazardous eruptions.
Mayon, one of the most active volcanoes in the country, first spewed ashes, which reached 2.5 kilometers (1.5 miles) in a phreatic eruption, lasting for nearly two hours on Saturday afternoon.
The authorities have warned people off a six-km radius around the volcano, and have issued a level 2 alert as concern grew over the possibility of stronger and more unsafe eruptions.
The phreatic or stream-driven eruption of Mayon Volcano in Legazpi, Albay started at 4:21 p.m. Saturday, which lasted for an hour and 47 minutes.
People living near Mount Mayon has been ordered to evacuate their homes amid increasing volcanic activity.
PHIVOLCS further said the public should refrain from entering the 6-kilometer radius of the Permanent Danger Zone (PDZ) to minimize risks from sudden explosions, rockfall, and landslides. Civil aviation authorities must also advise pilots to avoid flying close to the volcano's summit as ash from any sudden eruption can be hazardous to aircraft. It was at its most deadly in February 1841, when 1200 people were killed and lava buried a town. 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.
Renato Solidum, the head of PHIVOLCS, declared the Mayon is due for another eruption after having displayed abnormal behaviour since the end of past year.