Tsunamis are waves that can travel great distances in the ocean at high speed. The waves are usually calm in the open sea but grow taller in shallow coastal areas. As a result, large areas can be flooded in a short amount of time due to the enormous volumes of water. Tsunamis can be triggered by underwater earthquakes, landslides, and volcanic eruptions. They pose a devastating threat to coastal communities. Damage is mainly caused by extreme flooding, strong currents, erosion, and debris (e.g., trees and vehicles). The extreme destructive force can also affect inland areas, damaging buildings, roads, and other infrastructure, as well as endangering people and their livelihoods.
The hazard analysis of tsunamis is based on a frequency analysis of measured run-ups. Run-ups are the masses of water that hit the land during a tsunami.