The mechanism causing a tsunami is explained in water waves: "A tsunami can have a wavelength in excess of 100 km and period on the order of one hour. Because it has such a long wavelength, a tsunami is a shallow-water wave. Shallow-water waves move with a speed equal to the square root of the product of the acceleration of gravity and the water depth."

According to the explanation, at water depth of 4 kilometers a tsunami travels at the speed of 700 km/h.

There is an animated illustration of the tsunami in Chile in 1960, which traveled across the Pacific ocean, over 17,000 kilometers.