Manila, April 28 -- Philippine authorities on Monday raised the alert level for Mount Bulusan after the volcano in Sorsogon province, southeast of Manila, spewed a dark plume 4.5 km into the sky.
The Philippine Institute of Volcanology and Seismology raised the alert level from zero to one on a scale of five, or from normal to low-level unrest, after a phreatic eruption occurred at 4:36 a.m. local time, which lasted 24 minutes.
"The event produced a bent plume that rose 4.5 km above the crater before drifting west to southwest," the institute said in an advisory, adding that ashes blanketed villages around the volcano.
The institute said the volcano produced "rumbling sounds" approximately 15 minutes before the eruption.
The institu...