TSUNAMIS

A tsunami is a series of waves generated when water in a lake or in the sea is

rapidly displaced on a massive scale. Earthquakes, landslides, volcanic eruptions

and large meteorite impacts all have the potential to generate a tsunami. The

effects of a tsunami can range from unnoticeable to devastating.


The term of tsunami comes from the Japanese language meaning harbour (tsu) and wave

(nami). Although in Japanese tsunami is used for both singular and plural, in

English “tsunamis” is well-established as the plural. The term was created by

fisherman who returned to port to find the area surrounding the harbor devastated,

although they had not been aware of any wave in the open water. A tsunami is not a

sub-surface event in the deep ocean; it simply has a much smaller amplitude (wave

heights) offshore, a very long wavelength (often hundreds kilometers long), which

is why they generally pass unnoticed at sea, forming only a passing “hump” in the

ocean.


Tsunamis have been historically referred to as “tidal waves” because as they

approach land they take on the characteristics of a violent onrushing tide rather

than the sort of cresting waves that are formed by wind action upon the ocean (with

which people are more familiar). However, since they are not related to tides, the

term is considered misleading and its usage is discouraged by oceanographers.