Acehtsunami

As a tsunami leaves the deep water of the open-ocean and actions into the shallower water near the shore, it transforms. The tsunami‘s power flux, which is dependent on both its wave force and wave altitude, remains nearly steady. Consequently, as the tsunami’s speed diminishes, its height grows. This is known as shoaling. Because of this shoaling effect, a tsunami that is invisible at sea, may grow to be quite a few metres or more in height near the coast.

The increase of the tsunami’s waveheight as it enters shallow water is given by: shallow height

Where hs and hd are waveheights in low and deep water and Hs and Hd are the depths of the low and deep water. So a tsunami with a height of 1 m in the open sea where the water depth is 4000m would have a waveheight of 4 to 5 m in water of deepness 10 m.

Just like additional water waves, tsunamis begin to lose energy as they rush onto land - part of the wave energy is reflect offshore, while the shoreward-propagating wave energy is dissolute through bottom resistance and turbulence. Despite these losses, tsunamis still reach the coast with marvelous amounts of energy. Depending on whether the first part of the tsunami to reach the shore is a crest or a furrow, it may appear as a quickly rising or falling tide. Local bathymetry may also cause the tsunami to come into view as a series of breaking waves.

Tsunami have great erosion possible, stripping beaches of sand that may have taken years to build up and undermining trees and other coastal vegetation. Capable of inundate, or flooding, hundreds of metres inland past the typical high-water stage, the fast-moving water associated with the flood tsunami can crush homes and other coastal structures. Tsunamis may reach a highest vertical height onshore above sea level, often called a run-up height, of tens of metres.