MANILA—State volcanologists on Saturday said steam plumes recently rising out of Taal Volcano were caused by the "upwelling of hot volcanic fluids" in its crater, and warned that the volcano still remained unstable.
In a tweet, Phivolcs said the steam plumes in Taal's main crater has not been observed "during the hot daytime periods of upwelling."
The video accompanying the tweet showed a cloud of white steam being emitted from the volcano crater between 6:44 a.m. and 6:50 a.m. on Saturday.
The agency pointed out in its latest bulletin that the lake in the main crater generated the said plumes, at least 1.5 kilometers high, before it hovered to the southwest.
"Upwelling of hot volcanic fluids at the Main Crater Lake has been observed to form steam plumes, vertical jets and even water spouts when cool air or rainwater is upon the lake surface," Phivolcs explained.
Taal Volcano remained at Alert Level 2, which means it is in an "increased unrest."
While there have been no volcanic quakes recorded in the past 24 hours, according to Phivolcs, "elevated unrest" has been recurring and its condition remain unstable.
"Phivolcs reminds the public that at Alert Level 2, sudden steam-driven or phreatic explosions, volcanic earthquakes, minor ashfall, and lethal accumulations or expulsions of volcanic gas can occur and threaten areas within and around [Taal Volcano Island]," the institute said.
The agency reiterated that the entry to the island — Taal's permanent danger zone, especially in the vicinity of the main crater and Daang Kastila fissure, occupancy and boating on Taal Lake — is strictly prohibited.
The volcano, which sits on an island surrounded by a lake in Batangas province, had a steam-driven eruption on January 12, 2020, triggering an ash fall that reached parts of Metro Manila and nearby provinces.
The eruption displaced more than 700,000 people in Central Luzon, Calabarzon and Metro Manila.
Damage to infrastructure and agriculture in the provinces of Batangas, Cavite and Laguna was pegged at P3.4 billion, according to the National Disaster Risk Reduction and Management Council.