This is how tsunamis work, how we seek to protect ourselves, and which parts of the country are most at risk. The explosion from a volcanic eruption or the sudden collapse of a volcano itself can cause major displacement and tsunami waves. The tidal forces of the Earth, sun and the moon have nothing to do with tsunami waves. In deep water, tsunami waves move at high speeds (up to 800kmh or as fast as a jet plane). In open waters, the distance between two successive tsunami waves (what’s called the wavelength) can be more than 500km.

Source: Stuff March 12, 2021 16:00 UTC