CONCEPTS

What is a tsunami?

We explain what tidal waves are, and what their causes and consequences are. Also, are they different from tsunamis?

  1. What is a tsunami?

It is known as tidal wave (from the Latin mare , sea, and motus , movement ) or sometimes also as a tsunami (from the Japanese tsu , port or bay, and nami , wave) to a complex oceanic phenomenon in which waves of high energy and large size , which move quantities of water well above the ordinary waves of the wind and that can enter hundreds of meters on land, sweeping everything in its path.

Tsunamis should not be confused with oceanic movements produced by the tide, such as tidal waves, or with floods caused by storms, hurricanes and tropical storms. Unlike these, tsunamis are generated in most cases as a result of a significant tremor or earthquake (or tidal waves, as they occur in the seabed), since the formation of a large sea wave It requires the transmission of huge amounts of kinetic energy to the water.

Paradoxically, a minimum unevenness in the seabed, even a few centimeters deep, is sufficient to mobilize a huge mass of seawater that, by regaining its physical balance, transmits energy in a very energetic wave capable of traveling kilometers shortly time , practically invisible on the high seas, until reaching shallow waters and losing speed due to friction with the ground , however gaining it in height. This results in a sequence of huge waves.

Tidal waves are feared for their destructive capacity, as seawater violently enters the mainland, and is usually some of the biggest concerns immediately after an earthquake of considerable magnitude. The area of ​​the world with the most frequent presence of tidal waves is the one corresponding to the Pacific Ocean, in the so-called “fire belt” of enormous underwater seismic activity.

  1. Causes of a tsunami

Tidal waves are the product, just like earthquakes, of the displacements of tectonic plates below the earth’s crust . Such movements often lead them to collide, confront, and change their shape, generating a friction whose energy is transmitted in the form of vibration, in this case, to the waters.

Similarly, tsunamis are due 90% to tidal waves, or to earthquakes that occur very close to the coast. Other possible causes of a tsunami are the explosion of submarine volcanoes or the impact on the sea of large meteorites .

  1. Consequences of a tsunami

We have already mentioned the primordial and most feared consequence of the tsunamis: the tsunamis. The destructive capacity of gigantic and fast waves are widely feared in the coastal populations of the Pacific Ocean, and they have been proven time and again in their history of natural disasters.

On the other hand, tidal waves themselves can induce momentary or permanent changes in the distribution of ocean currents, or even in the flora and fauna of the seabed.

tsunami - samatra 2004
Tsunami in Samatra, Year 2004.
  1. Differences between tsunami and tsunami

Although they are normally used as synonyms, there is a technical precision regarding the use of the terms tsunami and tsunami.

By the first we refer to an earthquake that occurred at sea , that is, a violent tectonic movement that occurs on the seabed. The second term, on the other hand, is considered a consequence of said underwater tremor, since it strictly refers to the gigantic wave that is generated by transmitting the seismic vibration to the waters.

However, since 90% of tsunamis originate from tsunamis , although not all tsunamis necessarily originate a tsunami, they are usually used more or less indistinctly in common speech.

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