A restive volcano in the central Philippines spewed a column of ash as high as 4.5 km into the sky on Monday morning, prompting authorities to raise the alert level at Mount Bulusan and warn residents to stay out of a 4-km danger zone.
The Philippine Institute of Volcanology and Seismology (Phivolcs) raised Bulusan's alert status from 0 to 1 on its five-level scale, signalling low-level volcanic unrest and warning of possible phreatic eruptions.
Prior to the eruption, which occurred between 4:36 am and 5:00 am on Monday, the institute had recorded 53 volcanic earthquakes over a 24-hour period and local officials reported rumbling sounds.
Phivolcs also urged vigilance within an extended 2-km danger zone on the volcano's southeast sector due to the risk of rocks and other debris being ejected by the volcano, as well as rock falls and avalanches.
Civil aviation authorities were advised to warn pilots against flying close to Bulusan's summit.
Bulusan is one of 24 active volcanoes in the Philippines. The country lies is in the Pacific "Ring of Fire," where volcanic activity and earthquakes are common.

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