What natural event causes the majority of tsunamis?

What natural event causes the majority of tsunamis? Earthquakes cause the majority of tsunamis, particularly large, shallow earthquakes beneath the sea. When an earthquake abruptly lifts or drops part of the ocean floor, it displaces the water above it and creates a series of waves that can spread across an entire ocean basin.

Not every earthquake produces a tsunami. The most effective ones usually occur at subduction zones, where tectonic plates meet and one plate descends beneath another. A quake must also cause substantial vertical movement of the seafloor; a mostly horizontal slip may generate little or no tsunami.

Other natural events can produce tsunamis. Submarine or coastal landslides can push water suddenly, volcanic eruptions and flank collapses can generate waves, and very large meteor impacts could do so as well. These causes are important but much less common globally than earthquake-generated tsunamis.

The 2004 Indian Ocean tsunami followed a magnitude 9.1–9.3 megathrust earthquake off Sumatra. The 2011 Tōhoku tsunami in Japan likewise began with a magnitude 9.1 undersea earthquake. These events show how seismic rupture can transfer energy from the moving crust into the ocean.