The Philippine Institute of Volcanology and Seismology (Phivolcs) on Monday said Mayon Volcano might calm within a few weeks.
Meanwhile, the Department of Health (DOH) said a vaccine rollout in Albay will continue despite the threat of Mayon eruptions.
Phivolcs placed Mayon under Alert Level 2 last June 5, then upgraded it three days later to Level 3 which remained unchanged until now.
“From our computations around 16 million cubic meters of volcanic materials have been released. Compared to the 2009 eruptions which spewed some 20 million cubic meters of volcanic materials, there is now a slight difference, so we could wait for a little more time before it is finally over,” Phivolcs resident volcanologist Paul Alanis explained.
More than 40,000 residents were evacuated amid during the 2009 eruptions. From Alert Level 4 in December 2009, it was reduced to Level 3, and then Level 2, in January 2010.
“From our assessment, the eruptions may end in a few weeks,” he added.
Phivolcs described Mayon’s activities as “relatively quiet effusive eruption,” meaning lava steadily pours out of the volcano’s mouth.
Alanis also said the frequency of volcanic earthquakes has been increasing, with 834 quakes recorded since June 1 to the present time, or about two weeks, and 184 in just two days, or between July 16 and July 17.
He also noted the reappearance of “repetitive pulse tremors,” or a continuous tremor-like series of weak volcanic earthquakes at 11 a.m. on July 16.
Over 20,000 residents have been evacuated from Mayon’s six-kilometer permanent danger zone.
In a bulletin, Phivolcs said 238 rockfall events and three dome-collapse pyroclastic density current (PDC) events were also recorded.
The volcano emitted 1,689 tons of sulfur dioxide on Sunday.
“Alert Level 3 is maintained over Mayon Volcano, which means that it is currently in a relatively high level of unrest as magma is at the crater and hazardous eruption within weeks or even days is possible,” Phivolcs said.
A very slow effusion of lava flows from the crater was observed along Mi-isi gully extending up to 2.8 kilometers and along Bonga gully extending up to 1.4 kilometers.
Lava collapse was also seen along Basud gully up to four kilometers from the crater.
The plumes observed in the volcano were obscured.
Phivolcs served warning against heavy rainfall that could generate channel-confined lahars and sediment-laden streamflows in channels where PDC deposits are emplaced.
“Increased vigilance against pyroclastic density currents, lahars and sediment-laden streamflows along channels draining the edifice is also advised,” Phivolcs said.
Health Undersecretary Enrique Tayag told reporters that the displaced victims of Mayon will be given the bivalent vaccine to combat the threat of COVID-19 in the crowded evacuation centers.
“They are currently vaccinating the evacuees from primary-level doses up to the second booster with the Sinovac vaccine, although we coordinated with the Bicol government unit that they will be using the bivalent vaccines for health workers and senior citizens,” Tayag said.
Tayag also said mental health wellness was among the services provided by the department not only to the displaced victims, but also to the health workers.
“These health risks will eventually appear as time goes on. Many of them want to return to their normal lifestyle because their familiar environment is not here,” Tayag said.
As of July 17, the DOH reported no new cases of COVID-19 in the evacuation centers. The four previously confirmed cases have already yielded negative results and have been released from isolation.