Tsunami

Tsunami:.

Tsunamis can be generated when an underground earthquake occurs. When this happens, the sea floor elevates and subsides, causing a displacement of water. This displacement of water will lead to the creation of massive waves (In other words, a tsunami).

In some cases, 2 tectonic plates rub against each other, causing one of them to sink under the other. Usually, it is the denser oceanic oceanic plates that sinks under the less dense continental plates. This is especially effective in generating an earthquake.
In fact, the only requirement for the generation of a tsunami is any form of a disturbance that causes a displacement of water. This displacement of water removes the water mass from its position of equilibrium. In the cases of tsunamis which are caused by the occurrences of earthquakes, the disturbance comes from the moving or uplifting of the sea floor. Another way in which the water column may be disturbed is through submarine landslides. These landslides are in most cases accompanied by massive earthquakes, as well as collapses of volcanic structures. The reason is that a large portion of rock and sediments slump down slope and is subsequently spread along the sea floor. In a similar manner, a submarine volcanic eruption which is violent enough may create an impetuous force that lifts the water column, thus displacing it and generating a tsunami. Tsunamis may be caused from disturbances from above as well. For example, landslides and cosmic-body impacts such as meteorites displace the water from above, as the momentum from these falling bodies are transferred to the water body. However, these tsunamis are not much of a threat, as they dissipate quickly and rarely present danger.