The Philippine Institute of Volcanology and Seismology downgraded on Sunday the alert level for Taal Volcano from alert level four to alert level three in response to reduced activity 15 days after the island volcano erupted on Jan. 12.
But the institute warned that the lowering of the alert level does not mean that the threat of a hazardous eruption has disappeared.
Taal Volcano erupted on Jan. 12, prompting the institute to raise the alert level to four on a scale of five. Level four indicates the eruption could occur within days, and level five means a hazardous eruption is in progress.
Renato Solidum, the head of the volcanic institute, announced that the alert level for the island volcano, about 66 kilometers south of Manila, was lowered due to "decreased tendency towards hazardous eruption."
In its latest bulletin, the institute said Taal Volcano's condition in the two weeks following the phreatomagmatic eruption "has generally declined into less frequent volcanic earthquake activity, decelerated ground deformation of the Taal Caldera and Taal Volcano Island (TVI) edifices and weak steam/gas emissions at the main crater."
As a result, the institute said it has decided to lower the alert status of Taal Volcano from alert level four to alert level three to reflect the overall decrease in the level of monitoring parameters.
"Alert level three means that there is a decreased tendency towards hazardous explosive eruption but should not be interpreted that unrest has ceased or that the threat of a hazardous eruption has disappeared," the institute added.
Should an uptrend or pronounced change in monitored parameters forewarn a potential hazardous explosive eruption, the institute said alert level may be raised back to four.
"People residing within areas at high risk to base surges who have returned after the alert level was stepped down must thus be prepared for a quick and organized evacuation at such time," the institute warned.
The institute warned that "sudden steam-driven and even weak phreatomagmatic explosions, volcanic earthquakes, ashfall and lethal volcanic gas expulsions can occur and threaten areas within the volcano and nearby lakeshores."
It also advised people "to observe precautions due to ground displacement across fissures, frequent ashfall and minor earthquakes."
The institute also advised pilots to avoid flying close to the volcano as airborne ash and ballistic fragments from sudden explosions and wind-remobilized ash may pose hazards to aircraft.
More than 300,000 residents have been evacuated to safer grounds since the Jan. 12 eruption.
