Phivolcs may lower Mayon alert level further

MANILA, Philippines - The Philippine Institute of Volcanology and Seismology (Phivolcs) said yesterday it might lower the alert level at Mount Mayon in Albay from 3 to 2 in the next few weeks if the volcano’s activities, including volcanic earthquakes and rock falls, continue to decline.

“If the volcano’s activity continues to decline, we may lower the alert level to 2 in the coming weeks,” Phivolcs director Renato Solidum said in an interview over radio dzBB.

He said they will still have to observe the volcano for at least one more week.

Solidum said Alert Level 3 means magma is close to the crater, and eruption is possible within weeks.

Alert Level 2, on the other hand, indicates unrest probably of magmatic origin and could eventually lead to eruption.

On Saturday, Phivolcs lowered the alert level from 4 to 3, decreasing the area considered danger zones from eight kilometers to six kilometers radius from the crater.

However, the danger zone is at seven kilometers radius at the southeast portion of the volcano.

In its latest advisory, Phivolcs said its seismic monitoring network detected nine volcanic earthquakes and 30 rock fall events related to the detachment of lava fragments at the volcano’s upper slopes during the past 24-hour observation period.

Steaming activity was not observed due to thick clouds that covered the summit crater while pale crater glow was observed Saturday night.

Sulfur dioxide (SO2) emission rate, however, remained high at an average value of 2,094 tons.

Meantime, Cedric Daep, chief of the Albay Public Safety and Emergency Management Office (Apsemo), said they are going to do a remapping in order to identify possible new lahar routes after volcanologists confirmed that most of the five major channels along Mayon slopes were fully filled, a condition that practically restored the cone-shaped volcano’s surface which was scarred and fractured by previous eruptions.

Daep said a remapping is important to determine the new directions or pathways where lahar or floodwaters would flow should there be heavy rains or typhoons.

Ed Laguerta, resident volcanologist here of the Phivolcs, confirmed yesterday that the main channels of Mabinit, Buyuan and Bonga in Legazpi City; Bañadero in Daraga, and Padang-Lidong in the Legazpi-Sto. Domingo portion were already silted with lava.

With these gullies and channels all filled, Laguerta even estimated the volcanic ejecta at 35- to 40-million cubic meters, or about 10- to 20-million short of Mayon’s average ejected materials of 50- to 60-million cubic meters in every eruption interval.

Laguerta said they would be conducting aerial surveys to locate possible lahar paths.

“We will have aerial surveys to have an accurate observation of the potential new lahar paths now that the old channels can no longer accommodate additional materials,” Laguerta told The STAR. – With Cet Dematera