JAKARTA, Indonesia — Indonesian authorities raised the alert level for the highest volcano on Java island, saying Mount Semeru could blow up again after a sudden eruption earlier this month left 48 people dead and 36 missing in villages that were buried in layers of mud.
Indonesia's geological agency said Saturday it picked up increasing activity that could trigger an avalanche of lava and searing gas, similar to the Dec. 4 eruption, which was preceded by heavy monsoon rains that partially collapsed a lava dome on the 12,060-foot mountain.
About 282 million cubic feet of sand from the volcano's crater clogged the Besuk Kobokan River, which is in the path of the lava flow, Energy and Mineral Resources Minister Arifin Tasrif said.
"As a result, if there is another eruption, it would block the flow path and create new lava flows spreading to the surrounding area," Tasrif said, adding that the government had set up a new danger map and urged people to obey it. It raised the alert level to the second-highest.
The head of Indonesia's Volcanology and Geological Hazard Mitigation Center, Andiani, said villagers living on Semeru's fertile slopes are advised to stay 13 kilometers (8 miles) from the crater's mouth. She also stopped tourism and mining activities along the Besuk Kobokan watershed.