What kind of waves are produced by a tsunami? (small amplitudes and longwavelengths)

Tsunami waves are very different from tidal waves. A tidal wave is by definition a wave caused by ocean tides, whereas a tsunami is almost always caused by an earthquake under water.

Tsunami waves are also very different from normal wind-generated waves, which many of us may have observed on a local lake or at a coastal beach. Observers of a tsunami will understand these waves are more like a fast moving tide crashing into the shoreline.

Normal ocean waves are caused by the wind, weather, tides, and currents, whereas tsunamis are powered by a geological force. Tsunami waves are surface gravity waves that are formed as the displaced water mass moves under the influence of gravity and radiate across the ocean like ripples on a pond. Regular wind waves only involve motion of the uppermost layer of the water, but tsunami waves involve movement of the entire water column from surface to seafloor.

Both common ocean waves and tsunami waves have a crest and a trough and can be described by their period (time between two successive waves), wavelength (horizontal distance between waves), speed and amplitude (wave height)