The alert on Taal Volcano was raised one notch higher to Level 2, indicating "increasing unrest," Phivolcs said Tuesday.
The increased alert level means that "there is probable magmatic activity that may or may not lead to an eruption," Phivolcs said. Evacuation is not yet recommended.
Since Feb. 13, Phivolcs said the Taal Volcano network has so far recorded 28 volcanic tremor episodes, four low-frequency volcanic earthquakes, and a hybrid earthquake at shallow depths of less than 1.5 kilometers beneath Taal Volcano Island.
"The total number of volcanic tremor events has risen to 866 since the onset of increased activity on 13 February," Phivolcs said.
"Volcanic tremors have increased seismic energy compared to previously recorded episodes and ranged between 3-17 minutes in duration," Phivolcs said.
The public is reminded that entry to the Taal Volcano Island is strictly prohibited. Local government units meanwhile are advised to continuously assess previously evacuated barangays around Taal Lake for contingency and communication measures in case of renewed unrest.
"Residents of these barangays are advised to be always prepared, to keep calm and listen to information only from trusted or verified sources," Phivolcs said.