A tsunami is a series of powerful ocean waves caused by a sudden movement of water. Most tsunamis begin with large underwater earthquakes. When sections of the seafloor suddenly lift or drop, they ...

Any large movement of land that causes major displacement of ocean water—from earthquakes, landslides, or volcanic eruptions—can generate a tsunami. Tsunamis generated in Alaska have caused damage and ...

A powerful offshore earthquake in northern Japan triggered tsunami warnings Monday, sending tens of thousands scrambling to higher ground. Half a world away, it raises a simple question: How do ...