LEGAZPI CITY, Sept.19 (PNA)--The Philippine Institute of Volcanology and Seismology (Phivolcs), in its 8 a.m. bulletin on Monday, said alert level one remained in effect on Mt. Bulusan in Sorsogon.
Phivolcs raised the alert level on Bulusan on Friday after it spewed ash measuring 1.5 kilometers high, which it said may lead to a steam-driven eruption, or what it calls a “phreatic eruption.”
In Phivolcs’ terms, level zero means “normal” while level one denotes an “abnormal” behavior.
In its bulletin today, Phivolcs said it has recorded three volcanic earthquakes in the past 24 hours while steaming activity could not be observed due to thick clouds covering the summit of Bulusan.
It said data it obtained in August showed slight swelling at the slopes of Bulusan compared to that taken in May which Phivolcs said is an indication that “hydrothermal processes are underway beneath the volcano that may lead to more steam-driven eruptions.”
The agency reminded the local government units in Sorsogon and the public that entry to the four-kilometer radius Permanent Danger Zone (PDZ) is strictly prohibited due to the possibility of sudden and hazardous “phreatic eruptions.”
Civil aviation authorities also advised pilots to avoid flying close to the volcano’s summit as ash from any phreatic eruption can be hazardous to aircrafts.
The bulletin said people living within valleys and along river or stream channels, especially on the southwest and northwest sector of Bulusan, should be vigilant against sediment-laden stream flows and lahar should there be heavy and prolonged rainfall.
Mount Bulusan is around 70 kms southeast of Mayon Volcano in Albay and about 250 kms southeast of Manila, the Philippine capital.
The new alert level on Bulusan was recorded around a week since alert level one was also raised over Mt. Mayon.
On Sept. 8, Phivolcs raised the alert status of Mayon Volcano to alert level one.
Phivolcs, in its 8 a.m. bulletin today, also said “no magmatic eruption is imminent” or that of magma rising to the crater of Mayon.
It said its seismic monitoring did not detect any volcanic earthquake in the past 24 hours while wispy to moderate emission of white steam plumes that crept downslope towards the northeast was observed.
“No crater glow was observed last night,” it said.
Phivolcs reiterated that the six-km PDZ around Mayon is a no-entry zone to the public because of the perennial danger of life-threatening rockfalls, landslides or avalanches at the middle to upper slopes, sudden ash puffs and phreatic eruptions at the summit.
Cedric Daep, head of the Albay Public Safety and Emergency Management Office, has asked the disaster councils in the towns of Camalig and Guinobatan and the cities of Ligao and Tabaco to help secure the monitoring instruments of Phivolcs.
He said safeguarding the monitoring equipment on the restive volcano can determine accurate and timely advisories as well as evacuation procedures.
"These critical instruments can spell the difference between life and death on those who are still staying inside the six-kilometer PDZ," he said.
In an interview over local radio this morning, Daep said APSEMO personnel have been conducting a survey over the past week of the “actual population inside the 6-km PDZ up to the 8-km” extended danger zone of Mayon.
He stressed the importance of having an updated listing of the affected population in the danger zones so APSEMO will be prepared to undertake proper evacuation procedures when the need arises.
As both Bulusan and Mayon are on alert level one, this means Phivolcs is closely monitoring two active volcanoes in Bicol at present.
Phivolcs’ volcanologist Alex Baloloy, however, said a direct link between the activities of Bulusan and Mayon has yet to be established.
“Though both volcanoes exhibit somewhat similar abnormalities, the observed changes are isolated,” he said.(PNA) FPV/GVR/CBD