Tsunamis are frequently called “tidal waves”, but this term is not correct as tsunamis are unrelated to the tides. Tides result from the imbalanced, extraterrestrial, gravitational influences of the moon, sun and earthquake-related generation mechanism.
A tsunami is a series of waves most commonly caused by violent movement of the sea floor. A tsunami can be generated by any disturbance that displaces a large water mass from its equilibrium position. In some ways a tsunami resembles the ripples that radiate outward from the spot where a stone has been thrown into water, but a tsunami can occur on an enormous scale.
The movement at the sea floor that causes the tsunami can be produced by different types of violent geologic activity: earthquakes, underwater landslides or much less frequently by volcanic eruptions or meteorite impacts.