What is Tsunami? Write down its characteristics.

Tsunami meaning “harbour wave” It is a series of extremely long waves caused by a large and sudden displacement of the ocean due to earthquake, volcanic eruptions etc. When they reach the coast, they can cause dangerous coastal flooding and powerful currents that can last for several hours or days.
Characters of Tsunami waves are as follows:
Tsunamis generally consist of a series of waves, with periods ranging from minutes to hours
The effect of Tsunami would occur only if the epicentre of the tremor is below oceanic waters and the magnitude is sufficiently high.
The speed of the

wave in the ocean depends upon the depth of water. It is more in the shallow water than in the ocean deep. As a result of this, the impact of a tsunami is more near the coast and less over the ocean
Over deep water, the tsunami has very long wavelengths (often hundreds of kilometres long) when a tsunami enters shallow water, its wave-length gets reduced and the period remains unchanged, which increases the wave height.
Tsunamis have a small amplitude (wave height) offshore. This can range from few centimetres to over 30 m height. However, most tsunamis have less than 3 m wave height.