Taal Volcano has quieted down, but the country’s seismological agency sees a 30 percent probability of an explosive eruption, which could be similar to the 1754 blast that redesigned the landscape of Batangas province.
That probability figure is “very high” and the eruption will be quite dangerous to people within 14 kilometers of the volcano’s main crater, the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Thursday.Depending on the volcano’s activity, the probability may change in the coming days, Phivolcs Director Renato Solidum told reporters.
Maria Antonia Bornas, chief of Phivolcs’ volcano monitoring and eruption division, said the agency was looking into historical records and watching precursors to tell whether Taal was about to blow up.
Precursors
Among the precursors the agency has observed are ground deformation and earthquake swarms, both of which signify movement of magma—molten rock—in the bowels of the volcano, she said.
Earlier, Phivolcs said fissures had opened up in the ground in several towns in the volcano region, which meant magma was rising to the surface and an eruption could happen any time.
“The magma is already beneath the volcano, so the question is: Would it erupt or not?” Solidum said on Thursday.
“But looking at the history of Taal Volcano, its story does not simply end,” he said. “Sometimes, there could be months or years between eruptions, especially since the magma has been resupplied.”
Volcanologists earlier said the worst-case scenario would be an eruption similar to the 1754 event, which lasted for seven months, with the volcano going through low-key activity, explosive eruption, then lull before repeating the cycle.
An article published by Solidum, Bornas and several other scientists in a scientific journal included a description of the 1754 eruption by the parish priest of the now-defunct town of Sala named Buencuchillo. The friar said that between May 15 and June 2 of that year, Taal “quite unexpectedly commenced to roar and emit sky-high, formidable flames intermixed with glowing rocks, which, falling back upon the island and rolling down the slopes of the mountain, created the impression of a large river of fire.”
The eruption buried the towns of Taal, Tanauan, Lipa and Sala under ash and rocks, forcing their relocation farther from the volcano.
Base surge
Between Wednesday morning and Thursday morning, scientists recorded 467 quakes on Taal, including eight low-frequency tremors, and observed low sulfur dioxide emissions.
Solidum, however, said the risk of an eruption remained.
“For a huge explosion, we have that probability,” he said. “But there are bigger likelihoods of smaller eruptions, which can also produce base surges.”
Highly destructive and deadly, base surges are fast-moving flows of superheated gas, ash and volcanic rocks that travel horizontally. Moving at subsonic speeds, these can travel over water and reach lakeshore communities in Batangas.Tens of thousands of people from those communities have been staying in government-run shelters since the volcano suddenly came to life on Jan. 12. More than 4,000 of them have come down with common illnesses and been helped by government doctors.
To ease the anxiety of the evacuees, the Department of Health in Calabarzon has sent television sets to the shelters. Thirty-two sets were sent to the shelters in Santo Tomas and Tanauan, where most of the evacuees are staying, and 165 more would be sent to other emergency centers.
The Bureau of Customs has joined the gigantic effort of feeding the evacuees, donating seized tinned sausages for consumption in the shelters, according to a statement from the Department of Finance. The sausages were confiscated in 2018 but were cleared as still good for human consumption by the Food and Drug Administration, the statement said.
It said Customs Commissioner Rey Leonardo Guerrero had asked the agency’s offices at all ports to donate food for the evacuees. —WITH REPORTS FROM TINA G. SANTOS AND BEN O. DE VERA