Tsunami

well i was learning aabout waves the other day in physics … so than i remembered about tsunamis … so here is a post about what causes/triggers tsunami aight ?
enjoy ………

A Tsunami can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Such large vertical movements of the Earth’s crust can occur at plate boundaries. Subduction earthquakes are particularly effective in generating tsunami.
Submarine landslides (which are sometimes triggered by large earthquakes) as well as collapses of volcanic edifices may also disturb the overlying water column as sediment and rocks slide downslope and are redistributed across the sea floor. Similarly, a violent submarine volcanic eruption can uplift the water column and form a tsunami.
Tsunami’s are surface gravity waves that are formed as the displaced water mass moves under the influence of gravity and radiates across the ocean like ripples on a pond.
In the 1950s it was discovered that larger tsunami than previously believed possible could be caused by landslides, explosive volcanic action, and impact events when they contact water. These phenomena rapidly displace large volumes of water, as energy from falling debris or expansion is transferred to the water into which the debris falls. Tsunami caused by these mechanisms, unlike the ocean-wide tsunami caused by some earthquakes, generally dissipate quickly and rarely affect coastlines distant from the source due to the small area of sea affected. These events can give rise to much larger local shock waves (solitons), such as the landslide at the head of Lituya Bay which produced a water wave estimated at 50 – 150 m and reached 524 m up local mountains. However, an extremely large landslide could generate a “megatsunami” that might have ocean-wide impacts.
The geological record tells us that there have been massive tsunami in Earth’s past. These tsunami were so large that they caused landslides on the opposite coast triggering another massive tsunami, or “bounce back” tsunami. An example today would be a landslide equivalent to everything west of Portland, Oregon falling into the Pacific Ocean, resulting in a tsunami that would then hit the Chinese coast with enough force to erode the coast, triggering a landslide large enough to send a tsunami that would in turn inundate the U.S. West Coast and would wipe out Portland.