tsunamí

Tsunamë is the term used to describe a series of ocean waves with very long wavelengths caused by the rapid displacement of a large volume of water. The standard spelling in English is tsunami; tsunamë is a variant spelling encountered in some contexts, such as transliterations or creative writing, and does not indicate a distinct phenomenon.

Most tsunamis originate from sudden vertical movement of the seafloor during undersea earthquakes, though they can also be triggered by submarine landslides, volcanic eruptions, or, rarely, meteorite impacts. In the deep ocean, tsunami waves have long wavelengths and travel at high speeds with relatively small wave heights, making them difficult to detect far from their source. As they move into shallower coastal waters, the waves slow and their heights increase dramatically, producing the local flooding and run-up that can accompany landfall.

Impacts can be devastating across coastlines, including inundation, structural damage, and loss of life. Tsunamis can occur as a series of waves over several hours, with the largest waves not always arriving first. Preparedness relies on early warning systems, coastal monitoring, and public evacuation plans. Detection networks use seismic data, deep-ocean pressure sensors, and tide gauges to forecast arrivals and issue alerts.

Notable historical events include the 2004 Indian Ocean tsunami and the 2011 Tōhoku tsunami in Japan. Tsunamës, like tsunamis, are distinct from tides and storm surges, and mitigation emphasizes hazard assessment, land-use planning, and rapid local response to warnings.