MANILA, Philippines - Mayon volcano’s abnormal condition was sustained yesterday with a recorded rock fall and a bit intense crater glow, but the Philippine Institute of Volcanology and Seismology (Phivolcs) said there was no imminent threat of hazardous eruption.
Phivolcs raised the alert status at Mayon from zero (normal) to 1 late Friday afternoon, three weeks after the phreatic explosion that killed four European tourists and a Filipino guide.
Ed Laguerta, chief of Phivolcs in Bicol, said the slight increases in its pre-eruption characteristics prompted the agency to raise the alert level at Mayon.
But he clarified that it was not intended to create panic among the public, only to caution everybody, particularly local officials, to be on alert should the volcano’s abnormal condition worsen.
“Although our seismographs recorded only a rock fall-related tremor, but we are more concerned with what is causing the tremor. Because this suggests that there is an ongoing activity inside the volcano that triggers the shake,†Laguerta told --.
“Although this (abnormal condition) means that presently no magmatic eruption is imminent, it is strongly advised that the public refrain from entering the 6-kilometer radius permanent danger zone due to the perennial life-threatening dangers of rock falls, landslides or avalanches at the middle to upper slope, sudden ash puffs and steam-driven or phreatic eruptions from the summit,†Phivolcs said.
Active stream or river channels and those identified as perennially lahar-prone areas should also be avoided, especially during extreme weather conditions when there is heavy and prolonged rainfall.
Philvocs also noted a moderate emission of white steam plumes drifting northwest and west-southwest last Saturday. The sulfur dioxide emission was measured at an average of 131 tons per day.
“This figure means that Mayon’s abnormal behavior is sustained. At this time, we could not see yet an overall pattern whether it (Mayon’s condition) is going up or down,†Laguerta explained.
Philvocs also said that the ground deformation survey (precise leveling) done in the third week of May showed slight inflation of the edifice compared to February 2012, with the volcano still slightly inflated compared to January 2010 baselines.
Laguerta said a closer watch of the 2,462-meter volcano is necessary to avoid being caught flat-footed.
“After what happened last May 7 (eruption), we could not take chances this time. That’s why we are quickly and carefully analyzing even slight changes in its abnormal parameters,†he added.
Philvocs also recorded a volcanic earthquake at Taal volcano in Batangas yesterday.