MANILA, Philippines – The number of volcanic earthquakes recorded from Taal Volcano went up in the past 24 hours compared to the day before, though remaining relatively low versus during high points of the unrest.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said on Wednesday, February 12, that the Taal Volcano Network recorded 101 volcanic earthquakes in the past 24 hours. This is higher than the previous figure of 87.

Of the 101, there were 4 low-frequency events. This type of volcanic earthquake is “caused by cracks resonating as magma and gases move toward the surface,” according to the United States Geological Survey.

Phivolcs reminded the public that volcanic earthquakes show magma is still moving beneath Taal’s crater.

At the volcano’s main crater in the past 24 hours, there was again “weak emission of steam-laden plumes rising 50 to 100 meters high,” the same as during the previous 24-hour period.

But the sulfur dioxide (SO2) emission went down, measured at an average of 67 tons per day on Tuesday, February 11, from 105 tons on Monday, February 10. SO2 is a major gas component of magma.

Taal has been under Alert Level 3 since January 26, after it showed a “decreased tendency” towards a hazardous eruption. Before that, it was under Alert Level 4 for two weeks, starting January 12, as a hazardous eruption was imminent then.

The highest category is Alert Level 5, which would be raised if a hazardous eruption is already in progress.

Though the parameters being observed are registering lower figures now, Phivolcs has repeatedly warned the public that the threat has not disappeared.

Under Alert Level 3, these may still occur:

• sudden steam-driven and even weak phreatomagmatic explosions, which result from the interaction of water and magma
• volcanic earthquakes
• ashfall
• lethal volcanic gas expulsions

Areas in Batangas within a 7-kilometer radius from Taal’s main crater are still on lockdown. These are:

• Taal Volcano Island
• barangays of Bilibinwang, Subic Ilaya, and Banyaga in Agoncillo
• barangays of Gulod, Buso-Buso, and Bugaan East in Laurel

There are still 4,422 families or 15,920 persons staying in evacuation centers as of Wednesday, from a high of over 38,000 families.

The Taal unrest has affected over half a million people in Batangas, Quezon, Laguna, and Cavite. – Rappler.com