Phivolcs records increased unrest in Taal

MANILA – Some 383 volcanic earthquakes or quakes caused by movements or eruptions of magma from the volcano, were recorded in Taal for the past 24 hours, according to an advisory released on Wednesday by the Philippine Institute of Volcanology and Seismology (Phivolcs).

These included 238 episodes of volcanic tremor lasting from one to 12 minutes and 143 low-frequency volcanic earthquakes. This was higher than the previous day’s 158 volcanic quakes, Phivolcs said.

Alert level 2 (increased unrest) is maintained over the Taal Volcano.

According to Phivolcs, upwelling of hot volcanic fluids in the Main Crater lake occurred on Tuesday and generated 300 m-tall steam-laden plumes from active fumaroles on the northern side.

Sulfur dioxide (SO2) emission averaged 1,886 tonnes/day last April 12. Temperature highs of 71.8°C and pH of 1.59 were last measured from the Main Crater Lake last March 4 and February 12, respectively.

These parameters indicate persistent magmatic activity at shallow depths beneath the edifice, Phivolcs said.

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 (TVI).

Phivolcs reiterates that entry into the TVI, Taal’s permanent danger zone (PDZ), must be strictly prohibited.

Local government units are also advised to continuously assess and strengthen the preparedness of previously evacuated barangays around Taal Lake in case of renewed unrest.

Earlier, Phivolcs director Renato Solidum, Jr. said the appropriate alert level for a volcano is being determined depending on the earthquakes recorded, not only based on the number but also the type of earthquakes, location, depth, and energy of the quakes.

Other parameters, such as ground deformation, the chemistry of gases and water, and surface manifestations are also being considered, he said.