Wednesday, August 02, 2006
Mt. Mayon's volcanic activity confuses experts!
Mayon continued to puzzle yesterday volcanologists and even disaster control officials here on what specific actions to take particularly in the raising of the volcano's alert level to a higher scale or what order to give to the potential evacuees.
Ed Laguerta, the government volcanologist who has been able to witness Mayon eruptions since 1968, admitted that the Albay volcano's very long yet "passive" lava flow at present, that had already traveled to as far as 5.9 kilometers from its summit crater yesterday, is so far the longest lava flow event that it displayed even before an explosive eruption could have started.
Laguerta recalled that all the 1968, 1984 and the 1993 eruption episodes were also characterized by lava flows then followed by explosive explosions, but said that the lava only reached as far as four- to five kilometers from the crater.
"At present, Mayon's lava flow had already traveled almost six kilometers down the crater although explosive eruption has not yet even started," Laguerta said.
The scientist said that they cannot raise yet its alert level since no lava fountaining is observed, which is one of the major indicators for putting Mayon under alert level 4.
"We have to admit that this unusual lava flowing of Mayon makes us to re-assess our indicators in raising a volcano's alert level. This volcano is making us think," Laguerta said.
On the other hand, Cedric Daep, chief of the Albay Disaster Management Office, also admitted that they cannot yet order any evacuation since Phivolcs still maintain Mayon's alert level to 3.
"We cannot just order an evacuation without basis or at least recommendation from Phivolcs.
But everything is in place in case Mayon's alert level is raised to 4," Daep said, after he and Mayor Noel Rosal had conducted an occular inspection yesterday morning of the barangays to be affected, particularly Bonga, Mabinit and Buyuan, and alerted residents for an evacuation anytime.
Laguerta is resolved so far of merely recommending evacuation on a "case-to-case" basis, the first time the Phivolcs will be doing, in case lava moves closer to the populated portions of the villages at the foot of the 2,462-meter volcano.
"If lava would further advance down slopes, we will only recommended evacuation of those residents whose areas are likely to be hit by the incandescent materials. We will not recommend for total evacuation since not all areas are affected, in case lava reaches some of the inhabited areas," Laguerta said.
Ernesto Corpus, volcano monitoring chief of the Philippine Institute of Volcanology and Seismology (Phivolcs), had observed lava flow the other night at a distance of five to ten meters, and declared that the toe of the flowing incandescent materials were travelling at an average rate of four meters an hour at very low inclines in Barangay Mabinit here.
Corpus said that with this rate, lava is expected to touch the boundary of the six kilometer radius permanent danger zone today or tomorrow.
Phivolcs observed in its bulletin yesterday that lava had advanced at 200 meters in the past 24 hours, while its sulfur dioxide emission dropped to 7,418 tons.
At least 7,500 families from 10 villages will be evacuated anytime that Mayon's alert level is raised to 4.
Mayon started to emit lava on July 14 and volcanologists estimated that it is ejecting some one million cubic meters of volcanic materials everyday.
Laguerta, however, admitted that the possibility that it would still proceed to an explosive eruption remains very high due to the continued very high volumes of SO2 emissions.
"Although the possibility for Mayon to just culminate through lava flow is not very remote, its chance of going to a higher eruption level is also very possible," he said.