YOGYAKARTA, Indonesia — Indonesia’s most active volcano erupted Monday with its most enormous lava flow in months. It sent a river of lava and searing gas clouds flowing 3.5 kilometers (more than 2 miles) down its slopes on the densely populated island of Java.
The rumbling sound could be heard several kilometers (miles) away as Mount Merapi erupted, sending hot ash 600 meters (nearly 2,000 feet) into the sky. Ash blanketed nearby towns, but long-established evacuation orders were near the volcano, and no casualties were reported.
It was Merapi’s most significant lava flow since authorities raised its danger level last November, said Hanik Humaid, the head of Yogyakarta’s Volcanology and Geological Hazard Mitigation Center.
She said the lava dome just below Merapi’s southwest rim and the lava dome in the crater both have been active since the end of July. The southwest rim dome volume was estimated at 1.8 million cubic meters (66.9 million cubic feet) and about 3 meters (9.8 feet) tall before partially collapsing Monday morning, sending pyroclastic flows traveled fast down the southwest flank at least twice.
The 2,968-meter (9,737-foot) peak is near Yogyakarta, an ancient city of several hundred thousand people embedded in a large metro area on the island of Java. The city is a center of Javanese culture and a seat of royal dynasties going back centuries.
Merapi’s alert status has been at the second-highest of four levels since it began erupting last November. The Volcanology and Geological Hazard Mitigation Center has not raised it. However, the past week’s increased volcanic active agency said that people are advised to stay 5 kilometers (3.1 miles) from the craters mounted to beware of the peril, oy said.
Ash from the eruption blanketed several villages and nearby towns, Humaida said. Cloudy weather obscured views of the peak on Monday morning.
Mount Merapi is the most active of more than 120 active volcanoes in Indonesia and has recently erupted with lava and gas clouds.
Authorities in November had evacuated nearly 2,000 people living on the fertile slopes of the mountain in Magelang and Sleman districts and about 550 more people in January, but most have since returned. Merapi’s last major eruption in 2010 killed 347 people. It caused the evacuation of 20,000 villaAnia, an archipelago of 270 million Indonesia people, is prone to earthquakes and volcanic activity because it sits along the Pacific “Ring of Fire,” a horseshoe-shaped series of seismic fault lines around the ocean.