Phivolcs: Reduced sulfur emissions from Taal doesn't mean we're safe
Published Jan 22, 2020 12:00 am
By Alexandria Dennise San Juan
Reduced emissions of sulfur dioxide, a major gas component of magma or molten rock, were observed at Taal Volcano on Wednesday, but state volcanologists warned that the danger of an explosive eruption is still present as volcanic quakes persist and a volume of magma has reached close to the volcano's surface.
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))
Philippine Institute of Volcanology and Seismology (Phivolcs) Volcano Monitoring and Eruption Prediction Division chief Mariton Bornas said sulfur dioxide emissions from Taal Volcano further decreased, measuring at an average of 153 tonnes per day.
This sulfur dioxide level was lower than the 344 tonnes per day measured on Tuesday and the 4,353 tonnes per day recorded on Monday.
According to the United States Geological Survey, sulfur dioxide indicates that magma is near the surface and could be a sign that the volcano will erupt soon.
However, Bornas emphasized that a reduced sulfur dioxide level for two straight days does not mean that the public is already safe from Taal's possible explosive eruption.
"Puwedeng nababarahan lamang ang mga labasan ng SO2 (sulfur dioxide) or puwede ring nag-degas na 'yung ibabaw ng magma at hindi na makalabas 'yung SO2. Maraming pwedeng maging factors," she said.
(It’s possible that the SO2 is somehow being blocked, or it’s possible that the surface of the magma has degassed and the SO2 can’t be released. There are a lot of possible factors for this.)
Bornas said they need to study the overall trend to see if there will be a continuous downfall in the gas levels for them to evaluate if the activity in Taal is already weak.
"Hindi pa tayo pwedeng magtiwala sa dalawang mababang SO2, kailangan po nating makita 'yung overall trend, 'yung dire-diretsong trend ng pagbaba," the Phivolcs official added.
(We can’t trust in the two straight days of low SO2 levels, we need to see an overall trend of steady decline.)
Checking all parameters
According to Bornas, government volcanologists are weighing all parameters, including gas emissions and volcanic quakes, every day to check if it is already acceptable to lower the alert level.
In the agency's latest monitoring on Taal, Bornas noted that volcanic quakes recorded in the past 24 hours were "significantly weaker" compared to the days after its phreatic or steam-driven eruption on Jan. 12.
From Tuesday morning to Wednesday morning, the Philippine Seismic Network (PSN) plotted six volcanic tremors registered at magnitudes 1.5 to 2.4 with no felt event, while the Taal Volcano Network, which can record small earthquakes undetectable by the PSN, recorded 481 volcanic tremblors including eight low-frequency earthquakes also in the past 24 hours.
As these quakes persist, Phivolcs said there is still continuous magmatic intrusion beneath the Taal edifice, which may lead to further eruptive activity.
Despite a seemingly weaker activity at the surface crater of Taal where a weak emission of white steam-laden plumes reaching up to 50 to 500 meters high was observed, the state volcanology agency warned that the volcano has already "re-charged" and a new supply of magma is almost at the surface.
"Hindi ibig sabihin nito na dapat ay kampante na tayo. 'Yun ang pinaka-problema ng assessment natin sa magma ngayon, kasi ibig sabihin naka-daan na, sumampa na, so ano na 'yung gagawin ng nakasampa nang magma? That is the next question," Bornas said.
(This doesn’t mean we can be complacent. The problem with our assessment of the magma now is, the magma is close to the surface, but what will it do?”
"So, this is a dilemma, actually, kung paano natin i-interpret 'yung nakapondo na na magma na dumaan at bumitak ng lupa at nagsanhi ng pag-alsa ng Taal region."
(It’s a dilemma, how we are to interpret the stored magma that passed and created ground fissures that led to the elevation of Taal region.)
Not everyone can return
Should a downward trend in Taal Volcano's activity be established in the coming weeks, Bornas said that not everyone will be allowed to return, especially those who were living on the volcano island and other high-risk areas.
"Ine-evaluate natin yung probability na magdi-diminish yung activity ng Taal, at kapag tuluy-tuloy ang trend, mag-s-stand down tayo sa next alert level. But again, hindi po puwedeng sabihin na puwede nang pabalikin lahat. We will not recommend that," she said.
(We are evaluating the possibility that Taal’s activity will diminish, and when the trend is steady, we will stand down to the next alert level. But again, we can’t say we can let everyone return.)
Bornas said the agency will be discussing with the affected local government units (LGU) about what areas within the 14-kilometer radius zone from the volcano’s main crater will still be off-limits if the alert level goes down.
"Kung magbababa ng alert, mayroon lang puwedeng bumalik. Kailangan pa pag-usapan 'yan with the LGU, pero definitely nag-agree kami na ang Taal Volcano Island ay talagang off-limits 'yan," she said.
(If we lower the alert, there will be some who will be allowed to return. We need to discuss that with the LGU, but we both agree that Taal Volcano Island is really off-limits.)
Bornas also advised those who will be allowed to return to always be ready to evacuate again as Taal's hazardous explosive eruption might happen anytime.
"Kailangan nating i-emphasize na hindi ito nangangahulugan na puwede na tayong mag-relax. Ang kailangang gawin ng ating mga kababayan na papayagang bumalik kapag tayo ay nag-lower ng alert level, dapat sa araw-araw bawat oras, handa na silang lumikas in a moment's notice, nang mabilisan, dahil maaari pa ring magkaroon ng pagputok at magtaas muli ng alert level," Bornas said.
(We need to emphasize that this doesn’t mean we can relax. What our countrymen need to do when they return after we lower the alert level, is that every day, every hour, they should be ready to evacuate at a moment’s notice, quickly, because it’s still possible that an eruption will occur and the alert level will be raised again.)
Alert Level 4 still up
Alert Level 4, or the possibility of a dangerous explosive eruption within hours to days, remains in effect over Taal Volcano, after more than a week of its continuous spewing of steam, ash, and lava.
The current danger level is already a notch below the highest alert level of 5 which means that a hazardous eruption is ongoing.
Phivolcs strongly reiterates total evacuation of Taal Volcano Island and high-risk areas as identified in the hazard maps within the 14-kilometer radius from the main crater and along the Pansipit River Valley where fissuring has been observed.
Residents around the volcano are advised to guard against the effects of heavy and prolonged ash fall.
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))
Philippine Institute of Volcanology and Seismology (Phivolcs) Volcano Monitoring and Eruption Prediction Division chief Mariton Bornas said sulfur dioxide emissions from Taal Volcano further decreased, measuring at an average of 153 tonnes per day.
This sulfur dioxide level was lower than the 344 tonnes per day measured on Tuesday and the 4,353 tonnes per day recorded on Monday.
According to the United States Geological Survey, sulfur dioxide indicates that magma is near the surface and could be a sign that the volcano will erupt soon.
However, Bornas emphasized that a reduced sulfur dioxide level for two straight days does not mean that the public is already safe from Taal's possible explosive eruption.
"Puwedeng nababarahan lamang ang mga labasan ng SO2 (sulfur dioxide) or puwede ring nag-degas na 'yung ibabaw ng magma at hindi na makalabas 'yung SO2. Maraming pwedeng maging factors," she said.
(It’s possible that the SO2 is somehow being blocked, or it’s possible that the surface of the magma has degassed and the SO2 can’t be released. There are a lot of possible factors for this.)
Bornas said they need to study the overall trend to see if there will be a continuous downfall in the gas levels for them to evaluate if the activity in Taal is already weak.
"Hindi pa tayo pwedeng magtiwala sa dalawang mababang SO2, kailangan po nating makita 'yung overall trend, 'yung dire-diretsong trend ng pagbaba," the Phivolcs official added.
(We can’t trust in the two straight days of low SO2 levels, we need to see an overall trend of steady decline.)
Checking all parameters
According to Bornas, government volcanologists are weighing all parameters, including gas emissions and volcanic quakes, every day to check if it is already acceptable to lower the alert level.
In the agency's latest monitoring on Taal, Bornas noted that volcanic quakes recorded in the past 24 hours were "significantly weaker" compared to the days after its phreatic or steam-driven eruption on Jan. 12.
From Tuesday morning to Wednesday morning, the Philippine Seismic Network (PSN) plotted six volcanic tremors registered at magnitudes 1.5 to 2.4 with no felt event, while the Taal Volcano Network, which can record small earthquakes undetectable by the PSN, recorded 481 volcanic tremblors including eight low-frequency earthquakes also in the past 24 hours.
As these quakes persist, Phivolcs said there is still continuous magmatic intrusion beneath the Taal edifice, which may lead to further eruptive activity.
Despite a seemingly weaker activity at the surface crater of Taal where a weak emission of white steam-laden plumes reaching up to 50 to 500 meters high was observed, the state volcanology agency warned that the volcano has already "re-charged" and a new supply of magma is almost at the surface.
"Hindi ibig sabihin nito na dapat ay kampante na tayo. 'Yun ang pinaka-problema ng assessment natin sa magma ngayon, kasi ibig sabihin naka-daan na, sumampa na, so ano na 'yung gagawin ng nakasampa nang magma? That is the next question," Bornas said.
(This doesn’t mean we can be complacent. The problem with our assessment of the magma now is, the magma is close to the surface, but what will it do?”
"So, this is a dilemma, actually, kung paano natin i-interpret 'yung nakapondo na na magma na dumaan at bumitak ng lupa at nagsanhi ng pag-alsa ng Taal region."
(It’s a dilemma, how we are to interpret the stored magma that passed and created ground fissures that led to the elevation of Taal region.)
Not everyone can return
Should a downward trend in Taal Volcano's activity be established in the coming weeks, Bornas said that not everyone will be allowed to return, especially those who were living on the volcano island and other high-risk areas.
"Ine-evaluate natin yung probability na magdi-diminish yung activity ng Taal, at kapag tuluy-tuloy ang trend, mag-s-stand down tayo sa next alert level. But again, hindi po puwedeng sabihin na puwede nang pabalikin lahat. We will not recommend that," she said.
(We are evaluating the possibility that Taal’s activity will diminish, and when the trend is steady, we will stand down to the next alert level. But again, we can’t say we can let everyone return.)
Bornas said the agency will be discussing with the affected local government units (LGU) about what areas within the 14-kilometer radius zone from the volcano’s main crater will still be off-limits if the alert level goes down.
"Kung magbababa ng alert, mayroon lang puwedeng bumalik. Kailangan pa pag-usapan 'yan with the LGU, pero definitely nag-agree kami na ang Taal Volcano Island ay talagang off-limits 'yan," she said.
(If we lower the alert, there will be some who will be allowed to return. We need to discuss that with the LGU, but we both agree that Taal Volcano Island is really off-limits.)
Bornas also advised those who will be allowed to return to always be ready to evacuate again as Taal's hazardous explosive eruption might happen anytime.
"Kailangan nating i-emphasize na hindi ito nangangahulugan na puwede na tayong mag-relax. Ang kailangang gawin ng ating mga kababayan na papayagang bumalik kapag tayo ay nag-lower ng alert level, dapat sa araw-araw bawat oras, handa na silang lumikas in a moment's notice, nang mabilisan, dahil maaari pa ring magkaroon ng pagputok at magtaas muli ng alert level," Bornas said.
(We need to emphasize that this doesn’t mean we can relax. What our countrymen need to do when they return after we lower the alert level, is that every day, every hour, they should be ready to evacuate at a moment’s notice, quickly, because it’s still possible that an eruption will occur and the alert level will be raised again.)
Alert Level 4 still up
Alert Level 4, or the possibility of a dangerous explosive eruption within hours to days, remains in effect over Taal Volcano, after more than a week of its continuous spewing of steam, ash, and lava.
The current danger level is already a notch below the highest alert level of 5 which means that a hazardous eruption is ongoing.
Phivolcs strongly reiterates total evacuation of Taal Volcano Island and high-risk areas as identified in the hazard maps within the 14-kilometer radius from the main crater and along the Pansipit River Valley where fissuring has been observed.
Residents around the volcano are advised to guard against the effects of heavy and prolonged ash fall.