LEGAZPI CITY: The Philippine Institute of Volcanology and Seismology (Phivolcs) in Bicol warned of a bigger explosion of Bulusan volcano after it spewed gray clouds as high as 400 meters on Tuesday.
The explosion according to Phivolcs Bicol resident volcanologist Ed Laguerta, was bigger than the previous eruption that occurred last month.
“Bulusan volcano exploded twice first at 11:02 and 11:20 AM with ash column of one kilometre high. Quite bigger than the previous eruption,” Laguerta said.
An explosion type earthquake associated with rumbling sound took place while the emitted ash fell on the volcano’s southwest quadrant, affecting the municipalities of Juban and Irosin.
When asked if the explosion is a precursor for a bigger eruption, Laguerta said that a stronger volcanic activity can take place if there is a change in chemical composition.
Bulusan volcano some 70 kilometers southeast of Mayon volcano in Albay and about 250 km southeast of Manila is one of the country’s most active volcanoes.
The Bulusan eruption is different from Mayon volcano. Usually, Bulusan is steam-driven explosion while its last magmatic explosion occurred 40 years ago. Today’s eruption is classified as phreatic or steam-driven activity.
The “phreatic” eruption, occur when water makes contact with hot rock inside the volcano causing steam. Due to pressure build-up, the steam escapes through the crater causing an explosion.
Such explosions are typical to Bulusan during restive periods, when its hydrothermal system is disturbed or when steam accumulates and pressurizes at the shallow levels of the volcanic edifice, the Phivolcs official explained.
Meanwhile, the Civil Aviation Authority of the Philippines (CAAP) issued a Notice-to-Airmen (Notam) for airway closure on Tuesday until Wednesday due to the Bulusan eruption.
Pilots were advised to exercise extreme caution when passing airway W8 and B462 as Yellow Alert level has been raised in the area.
The CAAP said that ejected ash and volcanic fragments from Mount Bulusan are hazardous to aircraft while airway W9 between Legazpi and Malag is reportedly closed.
The country’s aviation regulator said they will issue updates as the condition of Mt. Bulusan changes.
Phivolcs warned the public and disaster officials to be on guard around the clock for more steam-driven or phreatic eruptions in the coming days.
With this, Col. Ceasar Idio commanding officer of the Army’s 903rd Brigade said military trucks are on standby for possible evacuation of residents living on the slopes of volcano.
Phivolcs warned the public not to venture within the four kilometre danger zone as explosion may happens anytime following the unrest condition of Bulusan volcano.