The state volcanology bureau said current monitoring parameters of Taal Volcano do not show "further activity and increased risk" despite remaining at an "abnormal" state.
Based on its report issued Wednesday, the Philippine Institute of Volcanology and Seismology (Phivolcs) said it is continuously monitoring Taal Volcano's activity where at least 29 volcanic quakes have been recorded from September 24 to 28.
One of these tremors, Phivolcs said, was "slightly felt" in Calaca, Batangas at Intensity II, while Intensity I or a "scarcely perceptible" shaking was recorded in the neighboring towns of Agoncillo, Laurel, and Lemery on September 25.
However, Phivolcs said the number and intensity of the volcanic quakes recorded still indicate the calming condition of Taal compared to the beginning of the year when it erupted.
'Slight swelling' observed
The agency added that there was still a "slight swelling" on the northwestern part of the volcano which was first observed in March through the continuous GPS stations around Taal.
Despite this inflation, which signals an accumulation of magma near the surface, Phivolcs noted that the rest of the Taal Volcano Island has reported almost no movement in recent months.
"The extent of the slight swelling in Taal volcano is still caused by its eruption in January. The ground deformation also continues to subside based on data trends from cGPS stations," it explained.
Meanwhile, a weak steaming or "fumarolic activity" was still observed in the Main Crater which has only raised from 5 to 20 meters in the past five days.
Alert Level 1 maintained
Alert Level 1 remains in place over Taal Volcano which means that sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within the Taal Volcano Island.
With this, the bureau emphasized that entry into the volcano island and its permanent danger zone, especially within the vicinity of the Main Crater and the Daang Kastila fissure, must remain "strictly prohibited."
"Local government units are advised to continuously assess previously evacuated barangays around Taal Lake for damages and road accessibilities and to strengthen preparedness, contingency, and communication measures in case of renewed unrest," it added.
The public, particularly residents near the volcano, were also advised to observe precautions due to ground displacement across fissures, possible ashfall, and minor earthquakes.
Aside from Taal, Phivolcs assured that it is closely monitoring other active volcanos in the country including Bulusan, Kanlaon, and Mayon, which are all at Alert Level 1.