Calbuco, a 2,000m volcano in Chile, has erupted twice in the past day, sending emergency services into overdrive. The eruption has prompted the evacuation of roughly 4,000 citizens from nearby cities and villages. It last erupted in 1972, Calbuco is a stratovolcano , and these are best known for having explosive eruptions – the infamous Krakatoa, Vesuvius and Mt. St. Helens volcanoes are all stratovolcanoes. We can only hope that Calbuco does not decide to blow its top as well.