Indonesia’s most active volcano erupted, sending a river of lava and clouds of scalding gas flowing 3,000 meters (9,850 feet) down its slopes.
The sounds of the eruption can be heard 18 miles (30 km) away, officials said. No victims were reported.
It was the largest lava flow on Mount Merapi since authorities increased its level of danger in November, said Hanik Humaida, head of the Center for Volcanology and Geological Hazards Mitigation in the nearby city of Yogyakarta.
She said the volcano’s lava dome is growing rapidly, causing hot lava and clouds of gas to flow down its slopes.
After the morning rain, the fall of ash turned into mud in several villages. More than 150 people, mostly elderly, living less than 3 miles from the crater, have been evacuated to tents set up for displaced people.
In November, authorities evacuated nearly 2,000 people who lived on the mountain in the districts of Magelang and Sleman, but most have now returned.
The alert is being maintained at the second highest level, and authorities have told people to stay out of the danger zone around the crater.
The 2,968 meter volcano on the densely populated island of Java is the most active of dozens of Indonesian volcanoes and has erupted repeatedly in recent times. Merapi’s last major eruption in 2010 killed 347 people.
Indonesia, an archipelago of 270 million people, is prone to earthquakes and volcanic activities because it lies along the so-called Pacific “Ring of Fire”, a series of horseshoe-shaped seismic faults.