Tsunamis strike as a surge of water, like a rapidly rising tide or a flood.
They rarely become “greater towering breaking waves”, as you might imagine, according to the US’s Tsunami Warning System.
Instead, they look like raging walls of water that may be preceded by a sudden low tide that exposes the ocean floor, reefs and fish.
Tsunamis can speed with the velocity of an aeroplane through deep water and slow down to the speed of a car once they hit the shore, charging onto land at about 30 to 50km/h.
The 2011 Japan earthquake smashed the coast with a surge of water up to 40 metres high, overtopping sea walls, killing 20,000 people and triggering the Fukushima nuclear disaster.
Tsunamis are waves triggered by earthquakes, underwater volcanic eruptions and submarine landslides. After an underwater earthquake, the seafloor rises and drops, which lifts water up and down. The energy from this pushes seawater, which transfers to waves.
Many people think of tsunamis as one wave. But they are typically multiple waves that rush ashore like a fast-rising tide.
Some tsunamis are small and don’t cause damage. Others can cause massive destruction.
With AP
AloJapan.com