Indonesia’s Mount Merapi erupted Saturday with avalanches of searing gas clouds and lava, forcing authorities to halt tourism and mining activities on the slopes of the country’s most active volcano.

Merapi, on the densely populated island of Java, unleashed clouds of hot ash and a mixture of rock, lava and gas that traveled up to 7 kilometers (4.3 miles) down its slopes. A column of hot clouds rose 100 meters (yards) into the air, said the National Disaster Management Agency’s spokesperson Abdul Muhari.

The eruption throughout the day blocked out the sun and blanketed several villages with falling ash. No casualties have been reported.

It was Merapi’s biggest lava flow since authorities raised the alert level to the second-highest in November 2020, said Hanik Humaida, the head of Yogyakarta’s Volcanology and Geological Hazard Mitigation Center.

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She said residents living on Merapi’s slopes were advised to stay 7 kilometers (4.3 miles) away from the crater’s mouth and be aware of the danger posed by lava.

Tourism and mining activities were halted.

The 2,968-meter (9,737-foot) mountain is about 30 kilometers (18 miles) from Yogyakarta, an ancient center of Javanese culture and the seat of royal dynasties going back centuries. About a quarter million people live within 10 kilometers (6 miles) of the volcano.

Merapi is the most active of more than 120 active volcanoes in Indonesia and has repeatedly erupted with lava and gas clouds recently. Its last major eruption in 2010 killed 347 people and displaced 20,000 villagers.

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Indonesia, an archipelago of 270 million people, is prone to earthquakes and volcanic activity because it sits along the “Ring of Fire,” a horseshoe-shaped series of seismic fault lines around the Pacific Ocean.

An eruption in December 2021 of Mount Semeru, the highest volcano on Java island, left 48 people dead and 36 missing.