Indonesia’s Mount Merapi erupted on Aug. 9, pouring ash and lava into the sky on Java, a densely populated island that’s home to more than a dozen active volcanoes. While hot ash from the eruption covered several villages and nearby towns, there was no immediate report of evacuations or deaths Mount Merapi, the most volatile of the more than 120 active volcanoes in Indonesia, has seen an increase in activity in recent weeks. On the morning of Aug. 8, the lava dome partially collapsed when a series of eruptions began, with the initial blast sending hot ash 3,280 feet (1,000 meters) into the atmosphere, according to Hanik Humaida, the head of Yogyakarta’s Volcanology and Geological Hazard Mitigation Center. The mountain spewed at least three new pyroclastic flows—avalanches of rock, ash, and volcanic gas—on Aug. 9, Humaida said, noting that it’s common for eruptions to last several days. Indonesia has more active volcanoes …