Tsunamis are series of waves usually caused by large undersea earthquakes. Learn the official U.S. message types, the natural warning signs, and why most earthquakes do not cause tsunamis.

Can an earthquake cause a tsunami? Learn which undersea quakes make tsunamis, the natural warning signs and how official tsunami alerts work.

The 2011 Japan earthquake and tsunami: how the magnitude 9 Tōhoku megathrust quake unfolded, why the tsunami was so deadly and what changed.

What to do during an earthquake outside, whether you are in a park, on a city street, on a hiking trail, at the beach or in a stadium.

What a Cascadia Subduction Zone earthquake is, how the 1700 quake was dated, the three types of Northwest earthquakes and how to respond on the coast.

Why Ring of Fire earthquakes are so common and so large: the subduction zones around the Pacific, where they are, and how risk varies along the belt.