Mount Bulusan in Sorsogon, Bicol, has shown increased signs of low-level unrest in the past 24 hours, according to the Philippine Institute of Volcanology and Seismology on Monday.

Based on their monitoring, the volcano registered 140 volcanic earthquakes from 12:00 a.m Sunday to 12:00 a.m Monday.

Hence, Bulusan volcano remains under Alert Level 1, meaning there is a low level of unrest with increased chances of steam-driven or phreatic eruptions.

The volcano’s plume is obscure, and its edifice is inflated.

Entry into the four-kilometer-radius permanent danger zone and entry without vigilance into the Extended Danger Zone are prohibited, Philvolcs noted.

The flying of aircraft close to the volcano's summit is also prohibited, as ash from sudden phreatic eruptions can be hazardous to the plane.