The eruption of Indonesia’s Mount Sinabung that shot ash 5 kilometers (3 miles) high also “annihilated” the mountain’s summit.
Before and after images from Indonesia’s Center for Volcanology and Geological Hazard Mitigation show an enormous chunk missing from the peak.
Volcanologist Devy Kamil Syahbana said the chunk, known as the “lava dome,” had a volume of at least 1.6 million cubic meters (56.5 million cubic feet).
The volcano in North Sumatra, which has been active since 2010, erupted explosively on Monday morning.
Hot ash clouds rolled down its slopes, traveling as far as 4.9 kilometers from the crater.
No-one was injured. Video showed screaming children fleeing a school outside the exclusion zone that surrounds the volcano as a billowing column of ash rose in the background.