By Alexandria San Juan
Taal Volcano continued to spew steam plumes on Monday, while volcanic activities such as gas emissions and tremors persisted, signifying continuous movement of magma underneath the volcano.
The main crater of the Taal Volcano is seen during an aerial survey done by government officials, more than a week after the eruption of Taal Volcano in Batangas. (Mark Balmores / MANILA BULLETIN FILE PHOTO)
In its latest bulletin issued Monday morning, the Philippine Institute of Volcanology and Seismology (Phivolcs) observed voluminous emissions of dirty-white to white steam-laden plumes from Taal Volcano rising 800 meters high.
Apart from steaming, Phivolcs noted that volcanic quakes continued to jolt within the volcano island, pointing to the movement of magma beneath the Taal edifice.
A total of 134 volcanic earthquakes were plotted by Taal Volcano's seismic monitoring network within its 24-hour observation period, including one low-frequency event.
Two of these events, Phivolcs said, registered at magnitude 3.2 and 2.3 around 4:20 a.m. and 5:42 a.m., respectively.
The first tremblor was felt at Intensity IV in Laurel and Agoncillo, Intensity III in Lemery, Batangas and Intensity II in Tagaytay City.
"These earthquakes signify magmatic activity beneath the Taal edifice that could lead to eruptive activity at the Main Crater," Phivolcs warned.
Alert Level 3 remains over Taal Volcano, which means there is a "relatively high unrest manifested by seismic swarms including the increasing occurrence of low-frequency earthquakes and/or harmonic tremors where some events are felt."
Phivolcs downgraded Taal's danger status from Alert Level 4 to Alert Level 3 on Jan. 26, two weeks after its phreatic or steam-driven eruption that forced thousands of nearby residents to evacuate after thick ash blanketed their homes.
Despite the lowering of Taal's alert status, the state volcanology agency reminds the public that sudden steam-driven and even weak phreatomagmatic explosions, volcanic earthquakes, ash fall, and lethal volcanic gas expulsions can still occur and threaten areas within the volcano island and nearby lakeshore communities.
With this, Phivolcs warned the public that entry into the Taal Volcano Island as well as into areas over Taal Lake and communities west of the island within a seven-kilometer radius from the Main Crater must be "strictly prohibited."
Local government units were also advised to assess areas outside the danger zone for damage and road accessibility and to strengthen preparedness, contingency, and communication measures in case of renewed unrest.
Residents were also asked to observe precautions due to ground displacement across fissures, frequent ash fall, and minor earthquakes.
Communities beside active river channels, particularly where ash from the main eruption phase has been thickly deposited, should increase vigilance when there is heavy and prolonged rainfall since the ash can be washed away and form lahars along the channels.