Tsunamis

Tsunami is a very large ocean wave y triggered by underwater earthquake, volcanic activies or landslides. These waves have unusually long-wavelength is excess of 100 kms, generated in the open ocean and transformed of catastrophic oscillations on the sea surface close to coastal zones. These normally occur in Pacific Ocean and are highly unexpected surrounding the Indian subcontiente.
In the open ocean, the tsunamis are harmless because of their small height (typically 30 - 60 cms.). However, as the race onto shallow water regions and pass into continental coast their speed diminishes which result in increase in the wave height in order to conserve de total energy. Typical speeds is in the open ocean are of the order of 600 to 800 km/hr. The tsunami's energy flux, with is depenent on both its wave speed and wave height, remains nearly constant. When it finally reaches the coast, a tsunami may appear as a series of breaking waves.