How cool is water? After an explosion breaks off a giant chunk of earth, the resulting wave is not something you’d like to be inside of. Tsunamis are caused by a couple of things: earthquakes, landslides, or volcanic eruptions–basically, when a huge amount of water is displaced by a huge amount of something else. This explosion and mini tsunami (which is still very violent) is a great scale model for how a much larger one might actually work.