Tsunamis are created primarily by the sudden displacement of a large volume of water, most often caused by undersea earthquakes along tectonic plate boundaries. When an earthquake occurs in a subduction zone, the overriding tectonic plate can suddenly spring upward, lifting the sea floor and the water above it, which initiates the tsunami
. This vertical movement displaces the water column, creating waves that radiate outward at high speeds across the ocean. Besides earthquakes, tsunamis can also be generated by other events that displace water, such as underwater landslides, volcanic eruptions, or even meteorite impacts. Landslides, for example, can move sediment along the seafloor and alter the equilibrium sea level, triggering waves
. Volcanic eruptions can violently displace water, and large meteorite impacts can cause similar effects, though these causes are less common
. Tsunamis have very long wavelengths and small wave heights in deep water, which is why they often go unnoticed at sea. However, as they approach shallow coastal waters, the waves slow down and increase dramatically in height, causing potentially devastating flooding and damage onshore
. In summary, tsunamis are created by:
- Sudden vertical displacement of the seafloor during undersea earthquakes, especially at convergent plate boundaries (subduction zones)
- Underwater landslides that displace water
- Volcanic eruptions that push water columns
- Rarely, meteorite impacts or other large disturbances in the ocean
These processes displace large volumes of water from their equilibrium positions, creating waves that travel across oceans at speeds up to 500 miles per hour, growing in height as they reach shallow coastal areas
