MANILA—The Philippine Institute of Volcanology and Seismology (Phivolcs) on Wednesday afternoon said satellite images of Taal Volcano showed that the crater lake has been drained of water.
New vent craters were also seen inside the northern part of the main crater.
“We received satellite images from our partner organization USGS (United States Geological Survey) showing the water vaporized, it disappeared from the main crater lake,” said Mariton Bornas, chief of Phivolcs' volcano monitoring and eruption prediction division.
“The new configuration now at the main crater is that there are separate vents where fumes and ash are released.”
Bornas said the drying up of the main crater lake is considered normal during heightened volcanic activity since fissures also appear on the volcanic island.
She added that before the 1911 explosion of Taal Volcano, there were other craters inside the main crater. But because the eruption inundated the main crater, they were no longer visible.
New fissures or cracks were also observed in the villages of Sambal Ibaba in Lemery town. This has been added to the list of fissures from other parts of Lemery (villages of Sinisian, Mahabang Dahilig, Dayapan, Palanas, Sangalang, Poblacion, and Mataas na Bayan), Agoncillio (Pansipit, Bilibinwang), Talisay (Poblacion 1, Poblacion 2, Poblacion 3, Poblacion 5) and San Nicolas (Poblacion).
Asked if the new fissures are a sign that an explosive eruption is about to happen, Bornas said: “The potential for an explosive eruption, based on our parameters, (we look at) mainly the earthquake activity.”
“It has not stopped. The earthquakes keep on coming. And they are considerable in magnitude for a volcanic earthquake so (it means that) magma is still rising,” she added.
Bornas said her group is also waiting for the new sulfur dioxide measurements to see if it has spiked, which would mean that magma is coming up to the surface.
“Fissuring is just a manifestation of the (magma) intrusion (or movement),” she said.
Since 1 p.m., Sunday, January 12, more than 500 volcanic earthquakes have been monitored in the area. Of the number, 169 were felt at Intensity I to V.
“Such intensive seismic activity probably signifies continuous magmatic intrusion beneath the Taal edifice, which may lead to further eruptive activity,” the Phivolcs bulletin read.
Bornas also clarified that what matters is the seismic energy of the earthquake and not the number.
She said that looking at the history of Taal volcano’s eruptions, there is a 50-50 chance that it will generate a strong eruption. “Looking at our monitoring, there is a large chance that there will be an explosive eruption,” she said.
The Phivolcs reiterated that Taal Volcano is on Alert Level 4, which means a hazardous explosive eruption is possible within hours or days. Taal Volcano Island should be evacuated, as well as high-risk areas within the 14-kilometer radius of the main crater.
The institute also warned residents against the effects of heavy and prolonged ash fall.