MANILA, Philippines — The Philippine Institute of Volcanology and Seismology (Phivolcs) has raised Alert Level 2 over Mayon Volcano in Albay amid increased sulfur emissions and rockfalls from the summit’s lava dome.
Phivolcs also monitored increased activity in Taal Volcano in Batangas, but said raising the alert level is not yet warranted.
In its Monday bulletin, Phivolcs said rockfall events in Mayon have increased in frequency since the last week of April.
These increased from an average of five per day to 49 events per day recorded from 5 a.m. of June 4 to 5 a.m. of June 5 – along with a total of 318 rockfall events and 26 volcanic earthquakes since April 1, 2023.
“The electronic tiltmeter monitoring shows the upper slopes to be inflating since February 2023 and electronic tilt monitoring indicate that Mayon is still inflated, especially on the northwest and southeast, since 2020,” Phivolcs added.
According to Phivolcs, it also recorded 576 tons per day of sulfur dioxide emission on April 29, compared to an average of 162 tons per day on May 23.
“These low-level volcanic earthquakes, ground deformation and volcanic gas parameters are overshadowed by recent steep increases in rockfall events which may possibly lead to further dome activity,” Phivolcs added.
“This means that there is current unrest driven by shallow magmatic processes that could eventually lead to phreatic eruptions or even precede hazardous magmatic eruption,” Phivolcs added.
State volcanologists said the public is strongly advised to be vigilant and desist from entering the six kilometer-radius Permanent Danger Zone to minimize risks from sudden explosions, rockfall and landslides.
“In case of ash fall events that may affect communities downwind of Mayon’s crater, people should cover their nose and mouth with a damp, clean cloth or dust mask. Civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden eruption can be hazardous to aircraft,” the Phivolcs added.
Taal under monitoring
There is no need yet to raise Alert Level 2 at Taal Volcano, Phivolcs said.
“This is not yet an indication to increase the alert level from Alert Level 1 to Alert Level 2. There are other parameters that we are looking at before we raise the Alert Level to 2, including the increase in seismicity, another is the volcano is inflated, among others,” Phivolcs director Teresito Bacolcol said.
According to Bacolcol, Phivolcs will continue to monitor Taal Volcano in case its heightened activities will result in another eruption. “Again we are closely monitoring the volcano. If there is an increase in the parameters, we will inform the public,” Bacolcol said.
On Sunday, Phivolcs reported that Taal released at least 5,831 tons per day of sulfur dioxide and an upwelling of hot volcanic fluids has been occurring at the main crater.
“The degassing we experienced yesterday (Sunday) is decreasing. Degassing is the interplay of magma, water and gas movement. This happens when volcanic materials are mixed with water. The degassing is accompanied by sulfur dioxide,” Bacolcol said.
Phivolcs said the volcano’s plume emissions reached 3,000 meters high.
Bacolcol added that the plumes produced volcanic smog or vog affecting municipalities of Balete, Laurel and Agoncillo, Batangas.
“The vog was accompanied by sulfur dioxide. We cannot see this but we can actually smell it. That is why yesterday, residents in Balete, Agoncillo and Laurel were affected by the foul smell,” he added.
“Based on the reports that we received, some residents experienced difficulty in breathing, throat and eye irritations. This is an indication of the prevalence of sulfur dioxide. We are advising the public to stay indoors and close their doors and windows or if necessary move to a safer place,” Bacolcol said.
The official noted the possibility that the vog will reach Tagaytay City cannot be ruled out.
“It will depend on the winds. There was a time that the vog reached Metro Manila, I think that was last year,” Bacolcol said.
Entry into Taal Volcano island – especially the main crater and Daang Kastila fissures – is prohibited, as there is always a danger of sudden phreatic explosion.
Stockpile
Department of Social Welfare and Development (DSWD) Secretary Rex Gatchalian has directed their field offices in the southern Tagalog and Bicol regions to prepare for the possible eruption of Taal and Mayon volcanoes, respectively.
“The concerned regional field offices have been directed to stockpile on their family food packs (FFPs) and ensure that they have sufficient standby funds as part of the preparation for both the Taal and Mayon volcanic unrest,” he said.
Gatchalian ordered their local officials to get the “historic data” in their respective regions to include the number of families affected, number of municipalities affected and the duration of the volcanic unrest.
“The historic data will be very helpful in determining the approximate number of FFPs that need to be stockpiled. It is very important to closely monitor the activities of Taal and Mayon and updates be sent in real time,” Gatchalian told department regional directors.
Phivolcs reminded that Taal Volcano is a permanent danger zone. It also observed a slight increase in sulfur dioxide emissions in the past two weeks.
DSWD Bicol regional director Norman Laurio reported that they have already alerted the provincial Quick Reaction Team and the chiefs of the Municipal Action Teams.
“We have instructed the QRTs and the MATs to have close coordination with their respective LGUs and provide updates if necessary. We will coordinate with PDRRMO (Provincial Disaster Risk Reduction and Management Office) for any updates or advisory,” he said.
No flights
The Civil Aviation Authority of the Philippines (CAAP) issued a notice to airmen (NOTAM) yesterday, barring aircraft from flying 10,000 feet from the surface of Taal and Mayon volcanoes due to unrest.
Flights are also advised to avoid flying close to the volcano’s summit, “as ash from the sudden phreatic eruption can be hazardous to aircraft.”
In Bicol, CAAP operates seven airports: Bulan, Sorsogon, Daet, Masbate, Naga and Virac, and the Bicol International Airport. — Delon Porcalla, Ralph Edwin Villanueva