THE Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday raised the alert status of Mayon Volcano in Albay to Alert Level 3 because of increased volcanic activity which may lead to lava flows.
Mayon’s status was raised to Alert Level 3 (increased tendency towards a hazardous eruption) three days after it was placed under Alert Level 2 (increasing unrest), from Alert Level 1 (low-level unrest), due to increasing rockfall events.
Mayon last erupted in January 2018 when it was under Alert Level 4 (hazardous eruption imminent) due to a steam-driven ash eruption. The alert was downgraded to Level 3 in March that year because of a decreased tendency toward a hazardous eruption.
The highest alert is Level 5 which means a hazardous eruption is in progress.
Taal Volcano in Batangas and Kanlaon Volcano in Negros Island remain under Alert Level 1.
Phivolcs said that since Alert Level 2 was raised at Mayon Volcano last Monday, “repeated collapse of the growing summit dome of Mayon Volcano has generated an increasing number and volume of rockfall events.”
In a bulletin issued at noon yesterday, Phivolcs said it recorded 267 rockfall events and volcanic earthquakes from Monday to yesterday, compared to 54 from Thursday to Sunday.
Phivolcs it observed three pyroclastic density current (PDC) on the Bonga (southeast) and Bansud (east) gullies yesterday morning.
“The PDCs lasted four to five minutes based on the seismic record and emplaced within a kilometer of the summit crater,” Phivolcs said.
It said data indicate “persistent inflation” of the southeast middle and upper slopes of the volcano since February.
Nevertheless, it said Mayon’s sulfur dioxide emission remains at baseline level.
“The overall monitoring parameters indicate that very slow extrusion of shallow degassed magma is ongoing and is incrementally increasing in rate; i.e., effusive magmatic eruption is taking place,” said Phivolcs.
It said Mayon “is exhibiting magmatic eruption of a summit lava dome, with increased chances of lava flows and hazardous PDCs affecting the upper to middle slopes of the volcano and of potential explosive activity within weeks or even days.”
Under Alert Level 3, evacuation operations are usually implemented.
Phivolcs recommended the evacuation of residents within the six-kilometer permanent danger zone (PDZ) “due to the danger of PDCs, lava flows, rockfalls and other volcanic hazards.”
Phivolcs also appealed for increased vigilance against pyroclastic density currents, lahars and sediment-laden stream flows along channels draining the edifice.
“Based on the current prevailing wind pattern, ashfall events may most likely occur on the south side of the volcano,” said Phivolcs.
Diego Mariano, deputy spokesman of the National Disaster Risk Reduction and Management Council, said authorities would ensure there are no people inside the PDZ.
“Though it’s a permanent danger zone, there are still some farmers there,” he said.
The Department of Social Welfare and Development (DSWD) said it has readied 1,500 big tents in Albay in anticipation of evacuation operations.
The DSWD said about 15,000 families are living within the 6-km PDZ.
DSWD Bicol regional director Norman Laurio in a report to Social Welfare Secretary Rex Gatchalian, said Legazpi City Mayor Carmen Geraldine Rosal and Disaster Risk Reduction Management (DRRM) officer Miladee Azur, “specifically requested for big tents in case of evacuation since Legazpi barangays are located within the 8-10 kilometer danger zone.”
In 2018, Mayon’s eruption lasted two months and 16 days, or from January 13 to March 29, with the number of families affected totaling to 23,786 staying in 96 evacuation centers. — With Jocelyn Montemayor
