A tsunami is a tidal wave that originates in the sea and hits a coast. The tsunami sweeps away everything in the ports and on the coasts: ships, trees, cars, and houses, but also people and animals. The water then flows back into the sea and causes further damage. A tsunami kills many people and animals.
A tsunami is usually caused by an earthquake on the sea floor, rarely by a volcanic eruption in the sea. When the seabed rises, the water runs out of space and is pushed to all sides. This creates a wave that spreads around like a circle. Usually, there are several waves with breaks in between.
In the middle of the sea, you don’t notice this wave. Because the water is very deep here, the wave is not that high yet. On the coast, however, the water is not as deep, so the waves have to move much higher here. This creates a real wall of water during the tsunami. It can grow over 30 meters tall, which is the height of a 10-story apartment building. This tidal wave can destroy everything. However, major damage is also caused by the material that they carry with them when the country is flooded.
Japanese fishermen invented the term “tsunami”. They were at sea and didn’t notice anything. When they came back, the harbor was destroyed. The Japanese word for “tsu-nami” means wave in the harbor.
Past tsunamis have claimed many lives. Today you can warn people as soon as you can measure an earthquake on the seabed. However, the tsunami spread extremely quickly, in the deep sea as fast as an airplane. If there is a warning, people have to leave the coast immediately and flee as far away as possible or, better still, up a hill.