MANILA — Slight increase in volcanic earthquakes and in the height of plume emission have been observed in Taal in the past 24 hours, the Philippine Institute of Volcanology and Seismology (Phivolcs) said Tuesday.
There were 87 volcanic earthquakes recorded, compared to 77 the previous day. One low-frequency event and two harmonic tremors were also recorded in the past 24 hours, lower than the 11 harmonic tremors recorded the previous day.
The earthquakes signify magmatic activity beneath the Taal edifice that could lead to eruptive activity at the main crater.
“Magmatic activity means processes involving magma, which include breaking of rocks and filling of cracks by magma or volcanic gas, movement of magma, and degassing of magma, boiling of underground water by magma,” said Phivolcs executive director Renato Solidum Jr.
Taal Volcano remains under Alert Level 3, which means sudden steam-driven and weak phreatomagmatic explosions, volcanic earthquakes, ashfall, and lethal volcanic gas expulsions may still occur in areas within Taal Volcano Island and nearby lake shores.
Meanwhile, weak emission of plumes measuring 50 to 100 meters tall has been observed. This is a little higher than the 20 to 50 meters tall plume emission the previous day.
Sulfur dioxide emission had an average of 105 tonnes on February 10.
Entry into the Taal Volcano Island, as well as into areas over Taal Lake and communities west of the island within the seven-kilometer radius from the main crater must be strictly prohibited, Phivolcs reiterated.
People are advised to observe precautions due to ground displacement across fissures, frequent ashfall, and minor earthquakes.
Local government units are likewise advised to assess areas outside the seven-kilometer radius for damages and road accessibilities and to strengthen preparedness, contingency and communication measures in case of renewed unrest.