Complex sentence: Notable eruptions, often causing many deaths, have occurred in 1006,1786,1822,1872, and 1930--when thirteen villages were destroyed and 1400 people killed by pyroclastic flows.
Split into simpler sentences: Notable eruptions, often causing many deaths, have occurred in 1006,1786,1822,1872, and 1930. Thirteen villages were destroyed in the later one, and 1400 people killed by pyroclastic flows.