A bird鈥檚 eye view of Bulusan volcano spewing ash as seen from Irosin town, Sorsogon province, south of Manila on June 13, 2022. (Photo by Mylene Sierra / AFP)
MANILA, Philippines 鈥� Bulusan Volcano in Sorsogon recorded 69 volcanic earthquakes and 42 volcanic tremors, according to the 24-hour monitoring of the Philippine Institute of Volcanology and Seismology (Phivolcs).
The monitoring posted on Saturday said that the 42 volcanic tremors lasted for one to 16 minutes.
Phivolcs earlier defined volcanic earthquake as an earthquake coming from an active volcano, where it differs from a tectonic earthquake, which is produced from faulting.
A volcanic tremor is 鈥渁 continuous seismic signal with regular or irregular sine wave appearance and low frequencies (0.5 to 5 Hz) where a tremor can be caused by magma flow, low-frequency earthquakes, or minor eruptions.鈥�
READ: Mt. Bulusan erupts anew
Meanwhile, the volcano also produced 1,215 tons of sulfur dioxide on Friday. This is slightly less than the 2,349 tons of sulfur dioxide released the day before.
Obscured plume was observed while the volcano edifice was inflated.
The volcano had a phreatic eruption last Tuesday that began at 7:43 p.m. and ended at 9 p.m. Its eruption last Monday prompted its alert level hike from Alert Level from zero (normal) to one (low-level unrest).
Phivolcs prohibits entry into the four kilometer-radius Permanent Danger Zone and entry without vigilance into the Extended Danger Zone. It also bans flying any aircraft near the volcano.
The state volcanologist added that sudden steam-driven or phreatic eruptions might occur from the volcano.