books.google.co.uk - Large caldera collapses represent catastrophic natural events, second only to large meteoritic impacts. In addition, some calderas are densely populated, making the risk extreme, even for moderate eruptions. Understanding caldera mechanisms, unrest and the danger of eruption is therefore a crucial challenge...http://books.google.co.uk/books/about/Mechanisms_of_Activity_and_Unrest_at_Lar.html?id=mk4Kvm3i4oEC&utm_source=gb-gplus-shareMechanisms of Activity and Unrest at Large Calderas
