LEGAZPI CITY: Mayon, the volcano with the perfect cone, is just starting to unleash her fury, Eduardo Laguerta, Philippine Institute of Volcanology and Seismology (Phivolcs) resident chief volcanologist said.
“What we saw on Monday and on Tuesday is just a start and a prelude to stronger explosive eruptions,” Laguerta said.
As this developed, the provincial government of Albay on Tuesday imposed alert level 5 contingency measures following threats of pyroclastic flow.
The 2,460-meter (8,070-feet) iconic landmark of Bicolandia has been letting off steam since last week and spewed ash on Monday and Tuesday with four to five-hour lulls in between.
Laguerta, who has been monitoring Mayon for almost 40 years, said Monday’s eruption was denser than the 9 a.m. explosion on Tuesday.
“Tuesday’s episode of explosion is just starting so we don’t know how long the eruptions will last but you see a series of pyroclastic flow. At least we have the element of time. Mayon is the most active volcano and is continuously replenishing her magma,” Laguerta added.
Phivolcs raised the volcano’s alert level to 4 on Monday after two successive 10-kilometer cauliflower-type ash columns billowed in the sky, generating heavy ashfall in the towns of Camalig and Guinobatan as well as Ligao City.
“If we go back to the historical eruptions of Mayon, the ash columns before was darker than today’s. That’s why we are looking closely at the parameters of Mayon but we’re not discounting the possibility that Mayon’s present activity may lead to a bigger and stronger explosion,” he said.
Laguerta said Phivolcs scientists are working together to scrutinize Mayon’s activity.
For the past 24 hours since Monday, Mayon’s vibration and rumbling sounds were getting stronger and were heard as far as 15 to 16 kilometers away from its slopes.
Lagueta said Phivolcs is looking at whether the parameters Mayon is showing now is similar to that of the 1897 eruption where the pyroclastic flow reached as far as the shoreline of Santo Domingo.
“From 1897 to 2018 it’s been more than a century when the longest ‘pangiriti-ngiti oson’ [pyroclastic flow] occurred that destroyed the town of Santo Domingo. The 1984 eruption also appeared to be very quiet with a weeklong lull before the sustained explosive eruptions then took place for a week,” he said.
Pyroclastic flow also known as a pyroclastic density current is a fast-moving current of hot gas and volcanic materials about 1,200 degrees celcius with a speed of up to 700km per hour.
Extended danger zone
As the provincial government of Albay imposed alert level 5, Cedric Daep, Albay Public Safety Emergency Management Office (Apsemo) chief, said they also imposed a nine-kilometer extended danger zone (EDZ).
“We did this so there will at least be a one kilometer buffer zone to prevent residents from going back to their communities in the wake of Mayon’s erratic character,” he said.
Mayon’s ash plumes drifted toward the villages of Legazpi City, Daraga and Camalig towns in the second district and in the municipality of Guinobatan and Ligao City in third district.
The heavy ashfall badly affected the southwest portion of the volcano covering Camalig, Guinobatan and Ligao City with a dark blanket of ash owing to the seasonal wind pattern.
Daep reiterated that the no man’s land must be avoided as disaster officials will no longer conduct rescue measures once a pyroclastic flow occurrs even in the extended nine-km EDZ.
They also recommended to Albay Power Energy Corp. to cut power supply in areas within the no man’s land to discourage people from returning to their houses in the area.
Following the imposition of the extended zone, tens of thousands of residents in Santo Domingo, Daraga, Camalig, Guinobatan, including the cities of Legazpi and Ligao were again directed to evacuate.