Phivolcs: Mayon lull could be prelude to similar eruption in 1984

(Updated 4:02 p.m.) Don't be fooled by restive Mayon Volcano's seeming quiet the last few days – it could be a lull similar to that 30 years ago, the Philippine Institute of Volcanology and Seismology said.

This was the warning of Phivolcs' Bicol resident volcanologist Ed Laguerta during a briefing in Albay Wednesday morning, radio dzBB's Allan Gatus reported.

Laguerta said their data suggested a lull before an eruption similar to what happened in 1984.

Phivolcs' chronology of historical eruptions of Mayon indicated that from September 9 to October 1984, Mayon had a Strombolian (low-level but can be long-lasting)-Vulcanian (with pyroclastic flow) eruption.

It was accompanied by ashfall, pyroclastic flow, lava flow and lahar.

Pyroclastic flow in the 1984 eruption affected the southeast and east of Mayon, including Bonga and Sto. Domingo areas.

Lava flow affected Camalig while ashfall affected Sto. Domingo and parts of Legazpi City.

In a report on "Balitanghali" on Wednesday, Phivolcs cited reasons for Mayon's relative calm.

It said there are two possible reasons for the lowered sulfur dioxide readings they have gathered: either there is a weather disturbance, or the mouth of the volcano has been clogged.

Since there is no weather disturbance, Phivolcs said, it is more likely the latter could be the case, Balitanghali's Isay Reyes reported.

During the aerial inspection on Tuesday, the lava dome's volume was measured to be 563,000 cubic meters, Phivolcs said.



Meanwhile, Albay Governor Jose Salceda posted on his Facebook account a report by state-run Radyo ng Bayan, quoting Laguerta as saying that Mayon's behavior now "is similar to l984 eruption."

"It was a (Vu)lcanian type of eruption. Meaning the eruption was associated with pyroclastic flow," he said.

Laguerta was quoted in the Radyo ng Bayan report as saying that before the 1984 eruption, there were two weeks of relative calm.

Before dawn of September 23, 1984, there were three successive explosions that produced an ash column 14 km high. The ash fell on the southeast part of the volcano.

Laguerta said a part of the summit was damaged but that perfect cone was restored in 1993 through volcanic activity. — Joel Locsin wit a report from Bea Montenegro /LBG, GMA News