The Philippine Institute of Volcanology and Seismology (Phivolcs) has recorded 106 volcanic earthquakes over the `past 24 hours at Mt. Bulusan in Sorsogon.
At least 48 were volcanic quakes lasting 20 minutes.
The volcano emitted 4,627 tons of sulfur dioxide last Sunday, the state bureau added.
Phivolcs also recorded voluminous emission of plumes reaching up to 500 meters high before drifting west northwest.
The volcano’s edifice was still inflated, Phivolcs said.
Sudden steam-driven or phreatic eruptions could occur.
Phivolcs prohibited entry into the four-kilometer radius permanent danger zone and entry without vigilance into the extended danger zone as well as the flying of any aircraft close to the volcano.
It also advised against flying aircraft close to Bulusan Volcano.
On Sunday, Bulusan Volcano had another phreatic eruption before dawn, lasting for 18 minutes.
It was the second phreatic eruption this month, following the one that occurred on June 5.
On Sunday, June 12, the municipalities of Juban, Casiguran, Irosin and Sorsogon were affected by ashfall from Bulusan Volcano after the phreatic eruption.
Some residents in Juban were evacuated, according to the National Disaster Risk Reduction and Management Council.
Airport authorities announced the cancellation of some flights for Sunday, June 12, 2022, due to Bulusan Volcano’s unrest.
A total of eight flights between Manila and Singapore and South Korea supposedly scheduled on Sunday have been rescheduled for Monday due to the volcanic activity in Mount Bulusan.
The Manila International Airport Authority (MIAA) recorded the following affected international flights:
• Jeju Air (7C) 2305 – Incheon-Manila
• 7C 2306 – Manila-Incheon
• Jetstar Asia (3K) – 1765 Singapore-Manila
• 3K 1766 – Manila-Singapore
• Asiana Airlines (OZ) – 703 Incheon-Manila
• OZ 704 – Manila-Incheon
• Korean Air (KE) – 623 Incheon-Manila
• KE 624 – Manila-Incheon
As of 10:53 a.m. Monday, the MIAA said no additional flights via Manila were affected.
Phivolcs on Sunday recorded another phreatic eruption that lasted for 18 minutes. This volcanic activity prompted airlines to cancel several domestic and international flights throughout the day.
Phivolcs Director Renato Solidum Jr. said both a volcanic tremor and a low-level background tremor signify hydrothermal activity or boiling of groundwater.
Compared to volcanic earthquakes that could only last for less than a minute, volcanic tremors are earthquakes that could last for more than a minute, hours or even days.
A low-level background tremor, on the other hand, can be detected through a continuous vibration logged in the seismic instruments.
Sulfur dioxide emission was 4,627 tons on June 12; while voluminous plume emission reached 500 meters high.
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.
Meanwhile, Alert Level 1 (low level unrest) is maintained over Mount Bulusan.