Jakarta, Indonesia (CNN) -- Indonesian officials have gone on high alert and have started evacuations as they warily monitor Mount Merapi, a volatile volcano in central Java that might erupt at any time. "The local government is coordinating to evacuate around 40,000 villagers to the pre-assigned shelters," Neulis Auliasari of the national disaster coordination board said Monday. Seismic activity has intensified, signaling that an eruption is imminent, according to Indonesian volcanologists. The 3,000-meter Merapi is famously unpredictable, though. A pyroclastic flow -- a fast-moving burst of blistering gases and rock fragments -- is a key concern. One killed two people in 2006 and another killed more than 60 villagers in 1994. About 1,300 people died when Merapi erupted in 1930.
About 40,000 nearby villagers have started evacuating . Seismic activity has intensified, signaling an imminent eruption . Merapi is famously unpredictable, though .