By ALEXANDRIA SAN JUAN
The threat of a hazardous eruption stays at Taal Volcano as intense tremors persist despite its generally weaker surface activity yesterday, the Philippine Institute of Volcanology and Seismology said.
A total of 103 volcanic quakes were plotted by the Philippine Seismic Network from Wednesday morning to yesterday morning. Fourteen of these were registered at magnitudes 1.4 to four and were felt at Intensities 1 to 3.
This brings the total number of temblors recorded to 566 since Taal’s phreatic or steam-driven eruption last Sunday.
Phivolcs Volcano Monitoring and Eruption Prediction Division chief Mariton Bornas said that the repeated tremors, which are slightly stronger for a volcanic earthquake, signifies that there is still a movement of magma beneath Taal.
This continuous magmatic intrusion beneath the Taal edifice may lead to further eruptive activity, Phivolcs warned.
In their latest analysis, Bornas noted that the amount of sulfur dioxide that has been emitted by the volcano spiked again, indicating that there is an upward movement of magma to the surface.
“Ang sulfur dioxide sa Taal ay tumaas ulit. Ibig sabihin, mayroon pang indication o senyales na mayroon pang magma na maaari pang i-putok ng malakas ang bulkan,” she said.
According to Bornas, Taal’s sulfur dioxide emission was measured at 4,186 tons per day as of Jan. 15 – significantly higher than the average 1,686 tons per day recorded on Jan. 14.
While there is still a continuous movement beneath Taal, State volcanologists are now looking at the possibility that there may be a lull for a considerable period of time due to low level or weak activity in its main crater.
Yesterday morning, Taal Volcano erupted short-lived dark gray ash plumes reaching only 500 to 800 meters high that dispersed ash southwest to west of the main crater.
Phivolcs also noted that Taal’s activity in the past 24 hours “generally waned” to weak emission of steam-laden plumes reaching 700 meters high that dispersed ash to the southwest.
“Sa stage na ‘to ngayon hindi pa rin nating tinatanggal ang panganib na maaari pa ring pumutok ng malakas ang bulkan, pero tinitingnan na rin natin ngayon ‘yung possibility na mag-lull ng may considerable na tagal,” she said.
“Tinitingnan natin kung ano ang ibig sabihin nitong mistulang pagtahimik ng bulkan. Sige-sige pa rin ang lindol, bagamat kumonti pero ‘yung lakas ay pareho lang, at tumaas ang volcanic sulfur dioxide, kaya kailangan natin i-evaluate ano ang ibig sabihin nun,” Bornas explained.
Historically, Bornas said that this somewhat prolonged eruptions of Taal is usual, similar to what happened in 1754 when Batangas experienced a devastating eruption lasting almost seven months.
“Pangkaraniwan sa volcanic eruption ‘yung mga lull, na tumatahimik muna, lalo na sa Taal, ‘yung mga prolonged eruptions katulad nung 1754 na pagputok nito,” she bared.
The 1754 eruption, which is Taal Volcano’s biggest eruption to date, buried several towns in Batangas under ash, volcanic rocks, and water.
“Medyo tricky kasi ‘yung kalagayan ngayon dahil tumahimik po ‘yung bulkan. Pero ‘yung parameters natin ay ganun pa rin – may malalaking, tumaas ang sulfur dioxide – kaya kailangan nating ievaluate kung gaano ito tatagal,” she said.
These parameters are among the reasons why Phivolcs still advised the total evacuation of the volcano island and high-risk areas identified in the hazard maps within the 14-kilometer radius from the main crater as a precaution for an “imminent explosive eruption.”
Phivolcs said they are receiving reports that there are some residents that are now going back to their houses near the danger zone due to Taal’s seemingly prolonged eruption.
“Ito yung isang medyo masalimuot na bahagi ng ating evacuation. Kapag medyo prolonged yung activity ng bulkan at may mga periods o panahon ng lull, medyo naiinip ang ating mga kababayan,” she said.
The Phivolcs official advised residents to do not risk their lives and instead remain in their evacuation while state volcanologists are still evaluating the behavior of Taal Volcano.
“Iwasan natin ang volcano island at huwag na muna tayong bumalik dito. Bigyan natin ng pagkakataon ang ating ahensya na pag-aralang mabuti kung ano ang ibig sabihin ng lull period na ito,” Bornas continued. “Huwag nating i-gamble ang ating buhay sa mga oras na ito dahil nandyan pa rin ang posibilidad ng malakas na pagputok ng bulkan,” she added.
