MANILA, Philippines – State volcanologists maintained Alert Level 3 for Taal Volcano in the province of Batangas on Sunday, February 2, as the unrest entered its 4th week.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said the Taal Volcano Network recorded 153 volcanic earthquakes in the past 24 hours, lower than the 182 in the previous 24-hour period.

The volcanic earthquakes included two 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 stressed on Sunday that the continuing earthquakes show “magmatic activity…that could lead to eruptive activity at the main crater.”

At the main crater, there was “weak emission of white steam-laden plumes 50 to 100 meters tall” in the past 24 hours. In the previous 24-hour period, the plumes had only been up to 50 meters tall.

The sulfur dioxide (SO2) emission also rose a bit, though still at a relatively low level. It was measured at an average of 97 tons per day, compared to the previous figure of 65 tons per day.

SO2 is a major gas component of magma. It indicates magma is relatively near the surface of a volcano.

Phivolcs reminded the public that these may still occur:

• sudden steam-driven and even weak phreatomagmatic explosions
• volcanic earthquakes
• ashfall
• lethal volcanic gas expulsions

Taal started erupting last January 12, when Alert Levels 2, 3, and 4 were raised in a span of just 5 hours. The volcano stayed under Alert Level 4 for two weeks, then it was downgraded to Alert Level 3 on January 26.

When Phivolcs downgraded Taal, however, it warned that the threat of a hazardous eruption remains. There is merely a “decreased tendency” towards such an eruption, but the unrest has not stopped.

The highest possible status is Alert Level 5, which would be raised when a hazardous eruption is in progress.

For now, areas in Batangas within a 7-kilometer radius from Taal’s main crater remain off-limits. These include:

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

The number of people who have been affected by the ongoing Taal eruption rose to 127,974 families or 478,876 persons on Sunday, said the National Disaster Risk Reduction and Management Council. They are in the provinces of Batangas, Quezon, Laguna, and Cavite.

Those staying in evacuation centers have gone down to 7,583 families or 26,588 persons as of Sunday.

When a 14-kilometer-radius danger zone was enforced during Alert Level 4, there were as many as over 38,000 families in evacuation centers. (WATCH: Pregnant Taal evacuees worry for the day they’ll give birth) – Rappler.com