LEGAZPI CITY, Jan. 18 (PNA) -- Local watchers of Bulusan Volcano in Sorsogon and Mayon Volcano in Albay reiterated today the warning initially issued to the public by the Philippine Institute of Volcanology and Seismology (Phivolcs) to avoid entry inside the mountains' Permanent Danger Zones (PDZ) due to the prevailing monsoon rains over Bicol for nearly a month now.
In Sorsogon, Crispulo Diolata, resident volcanologist at Phivolcs' Cabid-An monitoring station, said residents should not dare enter Bulusan's four-kilometer radius PDZ and its six-km extended danger zone on the southern slopes.
“Deposited thick ashfalls could be mobilized into lahar in case of heavy downpour due to the prevailing monsoon rains in the province,” he warned.
Diolata said that thick ashes ejected during the November explosion of Bulusan “merely dropped along its slopes” due to the absence of strong winds at that time.
"We would like to inform the public to refrain from entering the danger zones of Bulusan because heavy downpour is likely to mobilize the latest ejected ashes into lahar," he said.
Phivolcs’ latest bulletin is reminding people living within valleys and along river or stream channels, especially on the southeastern, southwestern and northwestern sectors of the volcano, to be vigilant against sediment-laden stream flows and lahars in case of heavy and prolonged rainfall.
It recorded four volcanic earthquakes on Bulusan in the past 24 hours.
Bulusan Volcano remains at alert level one, which means that hydrothermal processes are underway beneath the volcano that may lead to steam-driven or phreatic eruptions.
Phivolcs said pilots should avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft.
In Albay, volcano watcher Jude Mallorca said they were having difficulty making physical observations of Mayon in the past days due to thick clouds brought by the monsoon rains.
He said, however, that Phivolcs’ instruments have not yet detected any lahar movement along Mayon's slopes.
Mayon volcano remains under alert level one, which means it is in an abnormal condition.
Mallorca reiterated their warning to the public that while magmatic eruption is not imminent over Mayon, “the public should not enter the six-kilometer PDZ due to the occasional heavy downpour over Mayon.”
Phivolcs latest Mayon bulletin added that “active stream or river channels and those identified as perennially lahar-prone areas on all sectors of the volcano should also be avoided, especially during extreme weather conditions when there is heavy and prolonged rainfall."
It said there is also the perennial life-threatening dangers of rockfalls, landslides and avalanches at the middle to upper slopes, sudden ash puffs and steam driven or phreatic eruptions from the summit.
But despite the warning, Mallorca said some farmers and orchid pickers continue to be spotted inside the 6-km PDZ.
Three volcanic earthquakes were recorded over Mayon during the past 24-hour monitoring period.
Phivolcs maintains close monitoring of Mayon Volcano and will report any new development. (PNA) LAM/GVR/SMT/CBD/RSM