Tsunami Definition Earth Science

Tsunami waves hit the coast line, tsunami definition.
Tsunami Definition, 2020.

What is a Tsunami:

Tsunami, also known as a tidal wave, is a large wave that is formed due to a volcanic explosion or earthquake and advances at high speed on the surface of the sea

Tsunamis possess enormous destructive power and gain strength when they reach the Coastal Region, forming waves over 30 meters high.

Tsunami Definition

The word tsunami is of Japanese origin, tsu means "harbour" and namis expresses "waves", therefore, harbour waves, tsunamis do not necessarily happen in the harbour but can be anywhere on the coast.

  • Especially in the Pacific and Indian Oceans, as well as the Mediterranean Sea.

Despite how difficult it is to foresee when a tsunami may occur, some countries with the highest incidences and risks of suffering these phenomena are: Chile, the United States, Japan, Mexico, Ecuador, have an alert center.

Although it is not always possible to have the Certainty when it will happen. The alert systems allow to calculate the epicenter of a large underwater earthquake and the time it may take for a tsunami to arrive. 

To facilitate prevention, it is possible to use underwater sensors, radio telemetry, satellite, among other means to try to measure the behavior of waves and sizes.

Generally, the waves do not affect a single place, they move with the sea currents, such as: 

The earthquake produced in Chile in the year 1960, it produced a tsunami that killed approximately 5000 people and 14 hours later it reached Hawaii and 9 hours later arrived in Japan causing more deaths. 

Likewise, in 2004 in Indonesia, 11 countries suffered the ravages of the tsunami, such as: India, Indonesia, Thailand, Sri Lanka, among others.

There are films and documentaries that demonstrates the terrible consequences of a tsunami, just as it happens in the film of the impossible, directed by J.A Bayona, based on the true story of the 2004 Indian tsunami.

  • In English, the word tsunami is translated in the same way tsunami.

Tsunami causes

Tsunamis can be caused by underground landslides or volcanic eruptions. The vast majority of tsunamis occur from large earthquakes below the water surface, with a hypocenter at the depth point, and produce the abrupt vertical movement of the seafloor, so that ocean water is driven out of balance and when try to regain balance it generates waves. 

The tsunami waves travel along the ocean at about 805 km per hour and, in the high seas, they are practically imperceptible, but when they approach land, they begin to grow in height and energy, destroying everything around them.

Typically, before the tsunami hits, the sea recedes and it can take 5 to 10 minutes for the main wave to arrive. Also, before the tsunami, as a warning to society, micro-waves can occur, low tides, high tides until the sea completely withdraws and, only the great wave is expected with the capacity to destroy everything that appears in its path.

Consequences of the tsunami

  • They devastate entire cities.
  • Floods extensive coastal territories.
  • They destroy the seabed.
  • Lowland vegetation can be destroyed to a considerable extent, such as mangroves and grasses.
  • They can cause the extinction of certain scarce animals, such as sea turtles.

Tsunami types

  • minor, the waves are not more than a meter high caused by an earthquake considered minor.
  • Moderate, of magnitude III, the waves are greater than a meter and a half in height caused by strong tremors exceeding.
  • Destructive or strong, magnitude IV, generate waves of 10 - 15 meters high, caused by the order of 8.5 on the Richter scale.

Tsunami and earthquake

The earthquake is the trembling or shaking of the earth's crust, caused by internal displacement, which is transmitted over great distances in the form of waves. 

The earthquake is a natural phenomenon characterized by a strong tremors due to collisions of tectonic plates, geological faults or volcanic activity. Tsunamis are caused by underwater earthquakes that produce movements of sea water, as previously stated.

It is noteworthy that not all earthquakes generate tidal waves, only those of considerable magnitude that occur under the seabed and are capable of deforming it.