Twelve people, including eight soldiers, skiing on the slopes of a volcano in central Japan were injured Tuesday by flying rocks during a sudden eruption, officials said. One soldier later died. A rest house at the resort was hit by volcanic rocks, but the extent of damage was not known, resort official Yasuaki Morita said. Kusatsu-Shirane last erupted in 1983. Japan sits on the Pacific "Ring of Fire" and is prone to earthquakes and volcanic eruptions. An eruption of Mount Ontake in 2014 killed about 60 people. Several other Japanese volcanoes are considered unstable and have had small eruptions in recent years.