A tsunami is a series of large, powerful ocean waves caused by the sudden displacement of a massive volume of water, usually triggered by undersea earthquakes, landslides, volcanic eruptions, or meteorite impacts.
Main Characteristics
- Tsunamis are not the same as regular tidal waves; while normal waves are generated by wind or tides, tsunamis originate from seismic or geological activity that moves the sea floor.
- When a tsunami forms, waves can travel across oceans at speeds up to 800 km/h and can reach heights up to 30 meters upon reaching the shore, causing catastrophic damage to coastal areas.
- Tsunami waves are typically long-wavelength and may arrive as a series of surges called a "wave train," with intervals lasting minutes to hours between waves.
Causes of Tsunamis
- Submarine earthquakes are the most common cause, especially those that occur in subduction zones where tectonic plates converge.
- Other possible triggers include underwater or coastal landslides, volcanic eruptions, glacier calving, and even meteorite impacts.
- The sudden movement pushes or pulls the water column, sending waves radiating outward from the epicenter.
Impact and Damage
- As tsunami waves approach shallow coastal waters, their speed decreases, but their height increases dramatically, resulting in immense destructive power.
- Tsunamis can sweep away buildings, trees, and vehicles, inundate coastal areas, and cause prolonged flooding and damage that persists as multiple waves arrive and recede.
- The most devastating tsunamis in history have resulted in severe loss of life and property across entire ocean basins.
Additional Notes
- The term "tsunami" is Japanese for “harbour wave,” reflecting the phenomenon’s tendency to cause significant damage in coastal harbors and communities.
- Tsunamis can occur in large lakes, though they are most common and most destructive in the ocean.
In summary, a tsunami is a natural disaster involving a series of powerful, fast-moving waves created by seismic events or large disturbances under or near water, with the potential to cause immense destruction along coastlines.