Tsunamis are a series of powerful waves caused by a large and sudden displacement of water. Very large earthquakes below or near the ocean floor are the most common cause of tsunamis ─ but landslides, volcanic activity, and even meteorite impacts are also capable of generating tsunamis. While damaging tsunami events don't occur often, Ventura County's 42 miles of coastline make understanding tsunami risk an important part of living or visiting here.