MANILA - Restive Mayon Volcano remains under alert level 4 or in danger of an imminent hazardous eruption despite showing a decrease in gas and lava emissions, a state volcanologist said Saturday.

The Philippines' most active volcano was placed under alert level 4, the second highest level in a 5-tier warning system, on Jan. 22 after it spouted a 10-kilometer ash column.

• Alert level 4, itinaas sa Bulkang Mayon

On Saturday, gas levels emitted by the Mayon decreased to 1,583 tons per day from the estimated "3,000 plus (tons of gasses released) 2 days ago," said Ed Laguerta of the Philippine Institute of Volcanology and Seismology in a press briefing in Albay.

He said the volcano, which has continued to spew lava and ash over nearly two weeks, had also deflated by 1 millimeter.

"For the meantime, continuous ang lava flow pero wala masyadong nangyayaring significant," said the volcanologist.

The seeming "downward trend" of volcanic activity, however, is not an assurance that the Mayon Volcano will no longer erupt, Laguerta said.

"Kahit na tumigil 'yung lava at gas, kailangan pa din tingnan kasi baka nabara lang. Kung may natitira pang pressure sa ilalim, delikado pa rin," he said.

The alert level will only be downgraded when there are "no additional extrusions" and when a continuous decline in emission levels for at least 7 days will be observed, Laguerta said.

Meanwhile, the decampment of residents evacuated from communities near the volcano will only be ordered once the Mayon is placed under alert level 2, said Cedric Daep, action officer at the
Albay Public Safety and Emergency Management Office (APSEMCO).

The government is spending about P4 million a day to provide for thousands of evacuees in Albay who fled their homes after the Mayon started to rumble in mid-January, Daep said.

Authorities placed the number of evacuees at 79,282 as of Saturday, down from 84,000 earlier in the week.

• 'Hazardous' Mayon eruption feared as residents evacuate

The government has been preparing for a "3-month-long Mayon Volcano emergency" as it continued to spew ash and lava, causing at least P160 million in damage to farms and crops.

• PH prepares for 3-month-long Mayon Volcano emergency
• Farm damage due to Mayon activity hits P160M

As of February 3, the government has spent about P113 million in assistance to residents affected by the volcanic activity, Presidential Spokesperson Harry Roque said.