As the result, waves are formed as the displaced water mass, which acts under the influence of gravity, attempts to regain its equilibrium.

Earthquakes generate tsunamis when the sea floor abruptly deforms & displaces the overlying water from its equilibrium position.

Submarine landslides, which often occur during a large earthquake, can also create a tsunami. During a submarine landslide, the equilibrium sea-level is altered by sediment moving along the sea-floor. Gravitational forces then propagate the tsunami given the initial perturbation of the sea-level.

A violent marine volcanic eruption also can create an impulsive force that displaces the water column and generates a tsunami.

Above water (subarial) landslides and space born objects can disturb the water from above the surface. The falling debris displaces the water from its equilibrium position and produces a tsunami.