What is a Tsunami?
A tsunami is a large and powerful wave of water, sometimes reaching hundreds of feet in height, which rushes onto land from the ocean. Tsunamis can result from any large and abrupt disturbance of the sea surface, most often caused by submarine earthquakes.
What Causes a Tsunami?
The most common cause of a tsunami is underwater earthquakes. Earthquakes occur when two tectonic plates shift and collide, releasing energy in the form of seismic waves that travel through the Earth’s crust. When these waves reach the ocean, they interact with the seafloor, generating a tsunami wave. Volcanic eruptions, landslides, and meteor impacts may also cause a tsunami.
How Does a Tsunami Form?
Tsunamis’ tremendous wave heights are created by two factors: the displacement of a large mass of water in the ocean and the speed of the water’s movement. When the seabed moves, vast amounts of water are displaced, pushing the water into huge walls of water that can travel long distances across the ocean at speeds of up to 500 mph.
When the tsunami wave reaches shallower water near land, the wave slows down and increases in height, increasing the power and potential danger it carries. Tsunami waves can go on for several hours, with multiple waves crashing onto shore in succession for many hours. The most hazardous waves occur near the source area and plenty of warning time is available for residents located further away.
In some cases, the displacement of the seafloor can also cause a localized surge or inversion of the sea level and is accompanied by strong winds, powerful currents, and unusually loud and strange noises. This can be a sign that a tsunami is imminent if people observe it closely.
Conclusion
Tsunamis are powerful and destructive forces of nature. While they often occur without warning, they are usually caused by an underwater earthquake and preceded by a localized sea level surge. By being aware of the signs of a potential tsunami and understanding their causes, people can better protect their lives and their property.