MANILA – Although Mount Bulusan continues to emit voluminous plumes, the volcanic earthquakes for the past 24 hours have been fewer than the previous day, based on the Philippine Institute of Volcanology and Seismology's (Phivolcs) volcano bulletin on Tuesday.

Volcanic earthquakes are caused by movements or eruptions of magma from the volcano, compared to tectonic quakes which are caused by fault movements.

For the past 24 hours, seven volcanic quakes have been recorded in Mount Bulusan in Sorsogon, lower than the 29 volcanic quakes the previous day.

In both the 24-hour observation period, voluminous plume emissions 150 meters tall have been recorded. Plume emission also continues to drift northwest.

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) has been hoisted over Mount Bulusan since Sunday when a 17-minute phreatic eruption and steam-rich gray plume around a kilometer high were recorded. (PNA)