Although tidal waves and tsunamis are both sea waves, they are two completely unrelated phenomena. Tsunamis are ocean waves triggered by large earthquakes that occur near or under the ocean. They can also be caused by volcanic eruptions, submarine landslides, or onshore landslides that cause large volumes of debris to fall into the ocean. Tidal waves are shallow water waves caused by the gravitational interactions between the Sun, Moon, and Earth. However, at one time the term “tidal wave” was used to describe what we now call tsunamis, which may account for the frequent confusion between the two.