MANILA – 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 are affected.

The Philippine Institute of Volcanology and Seismology (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 has been advising pilots to avoid flying close to the volcano’s summit as ash from a sudden phreatic eruption can be hazardous to aircraft.

For the past 24 hours, Phivolcs has recorded 126 volcanic earthquakes in Bulusan. The figure included 20 volcanic tremors each about 20 minutes long.

Phivolcs Director Renato Solidum Jr. on Monday said for Bulusan, 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. (PNA)