The Philippine Institute of Volcanology and Seismology (PHIVOLCS) said it expects another phreatic eruption at Mt. Bulusan in Sorsogon.
The agency said it noted an increase in seismic activity and that Mt. Bulusan generated 149 volcanic earthquakes in the past 24 hours.
“Most of these were weak and shallow events, but may indicate that a phreatic eruption could possibly occur within the next few hours,” the
agency added.
PHIVOLCS underscored that Alert Level 1 remains over Bulusan, which indicates continued abnormal activity in the area, GMA News reported.
The agency posted a reminder to local government units and the public that entry into the 4-kilometer Permanent Danger Zone (PDZ) “must be
strictly prohibited.”
The PHIVOLCS also urged “vigilance” within the 2-kilometer “danger zone” in the southeast area of the volcano. PHIVOLCS said it is
closely monitoring Mt. Bulusan.
The Department of Health reported that it “mobilized” P84.5 million worth of supplies for residents in affected areas.
While most of these earthquakes were weak and shallow, Phivolcs Director Renato Solidum Jr. confirmed that the increased number of
volcanic quakes may indicate that a phreatic eruption could possibly occur.
Volcanic earthquakes are caused by movements or eruptions of magma from the volcano. Phreatic eruptions, on the other hand, occur due to
shallow hydrothermal activity.
Meanwhile, 24 tons of sulfur dioxide emission was recorded on June 9. Moderate plume emission 100 meters high was also recorded.
Volcanic plumes are columns of hot volcanic ash and gas emitted into the atmosphere during an explosive volcanic eruption. A weaker
eruption is based on the height of the plume coming out of the crater.
Alert Level 1 (low-level unrest) is maintained over Mount Bulusan.
Entry into the 4-kilometer radius permanent danger zone (PDZ) must be strictly prohibited, and vigilance in the 2-kilometer extended danger
zone on the southeast sector must be exercised due to the increased possibilities of sudden and hazardous phreatic eruptions.
Pilots are advised to avoid flying close to the volcano’s summit as ash from a sudden phreatic eruption can be hazardous to aircraft.
Phivolcs also urge people living within valleys and along river or stream channels, especially on the southeast, southwest, and northwest
sector of the edifice, to be vigilant against sediment-laden streamflows and lahars in the event of heavy and prolonged rainfall should a
phreatic eruption occur.
A volcano’s alert level is being determined depending on the numberand type of earthquakes recorded, including the location, depth, and
energy of the tremors.
Other parameters, such as ground deformation, the chemistry of gases and water, and surface manifestations are also being considered.