PHIVOLCS: 6 PDC events, eruption on Mayon summit

An eruption occurred on the summit of Mayon volcano, said Philippine Institute of Volcanology and Seismology (PHIVOLCS) director.

"Right now, there is an eruption on the summit," said Dr. Teresito Bacolcol, during an interview on Unang Balita Friday.

He also said that the agency recorded a total of six pyroclastic density current or PDC events.

"The pyroclastic density current is the new term of pyroclastic flow," he explained.

"Hindi na po natin ginagamit ang term na pyroclastic flow kasi nagkakaroon ng misimpression ang mga tao na it's just a flow. When, in fact, it's very fast moving (for) several kilometers ang tinatakbo niya per hour," he added.

The speed of the pyroclastic density current is hundreds of kilometers per hour.

"Kahapon we recorded a total of six pyroclastic density current or PDC events. This would imply a continuous supply of magma to the surface dislodging all the new surface of the lava dome," said Bacolcol.

Based on PHIVOLCS' 5 a.m. bulletin, 199 rockfall events were also monitored in the volcano.

The PHIVOLCS continues to monitor Mount Mayon, which has been placed on Alert Level 3.

Bacolcol said there are parameters that they observe closely before an alert level is raised.

"For example ang sulfur dioxide emission, kapag dumadami na. Kasi, as of now, nasa lower than the background level yung sulfur dioxide emission it's just 332 tons per day. Ang background niya is 500 tons per day, so mas mababa pa siya," he said.

A moderate emission of plume reaching up to 800 meters tall was seen from the volcano, according to PHIVOLCS’ latest bulletin.

Another parameter, meanwhile, is seismicity, Bacolcol said.

"Kahapon walang volcanic earthquake kaming na-record. Between June 5 to June 8, dalawa lamang. So, isa yan sa mga parameters na tinitingnan namin," he said.

"Meron din yung increase in mass flux, nagkakaroon ng longer lava flows, frequent pyroclastic density currents, and lava fountaining. Isa din sa tinitingnan namin ay yung minor explosions," he added.

Alert Level 4 is defined as the imminent hazardous eruption. So far, the PHIVOLCS official said the eruption is contained at the summit of the volcano.

He said there is a thin layer of ashfall observed and that this may have been from the PDC events that occurred.

Keep clear of danger zone

"We remind people huwag muna pumasok sa permanent danger zone or within six kilometers," said Bacolcol.

"Pwede kasi magkaroon ng rock fall events, pwede magkaroon ng landslides, pwede rin magkaroon ng sudden eruption. so, we recommend the six-kilometer danger zone for a reason. So, sana po sundin po natin ito," he added.

On Thursday evening, PHIVOLCS posted a video showing "incandescent rockfall" flowing from the summit of the volcano.

"Rockfall debris deposited on the Miisi and Mabinit Gullies as a result can be imaged as glowing lobes of debris by long exposure photography," PHIVOLCS said.

PHIVOLCS raised the alert level in Mayon Volcano from 2 to 3, signifying "increased tendency towards a hazardous eruption." -- with Joviland Rita/BAP/KBK, GMA Integrated News