This chart of tsunami waves is from Krakatu in 1888, but it’s a prime example of what will happen again. “…I can guarantee that somewhere on Earth, within at least some of our lifetimes, another volcano will suffer a catastrophic collapse that sends enormous waves of water surging for vulnerable coastlines, killing hundreds, thousands, or even tens of thousands of unsuspecting people. And those of you living on quiet coasts far from any active volcano aren’t immune to the threat.”