The tsunami definition states that “A series of waves triggered by the movement of a large amount of water in a water body, typically an ocean or a large lake”.
The tsunami definition tells us that these are waves so tsunamis are also known as tidal waves. Tsunamis and tides both create inland water waves, but the inland movement of water in the case of a tsunami can be much greater, giving the appearance of an extremely high and strong tide called a tsunami wave.
In this article on tsunamis, we will learn about the causes and effects of the tsunami, types of tsunamis, and more tsunami information.
What is the Spelling of the Tsunami?
Tsunami is derived from the Japanese word “soo-NAH-mee”. The tsunami meaning in Japanese is “harbour wave”. Since in Japanese words, there is no ‘T’. So when spelt the initial 'T' is often silent which fits with the phonological rules of English.
So, the correct spelling of Tsunami is “Tsunami” with ‘T’ a silent letter.
How Tsunami Occurs?
Tsunamis may be caused by earthquakes, volcanic eruptions, and other underwater explosions such as detonations, landslides, glacier calvings, meteorite impacts, and other man-made disruptions above or below water.
The movement of a large amount of water or the perturbation of the sea is the primary cause of a tsunami. Earthquakes, landslides, volcanic eruptions, ice calvings, and, more rarely, meteorites and nuclear tests are all accounted for the water displacement.
1. The Tsunami Caused By Earthquake
Because of the vertical component of movement involved, a tsunami can be produced when thrust faults associated with convergent or destructive plate boundaries move suddenly, resulting in water displacement.
When they enter shallow water, they rise in height, a process known as wave shoaling. A tsunami can occur at any tidal state, and coastal areas can be inundated even at low tide.
Examples of tsunamis caused by earthquakes are the Aleutian Islands earthquake in 1946, the Valdivia earthquake in 1960, the Alaska earthquake in 1964, the Indian Ocean earthquake in 2004, the Tōhoku earthquake in 2011.
2. The Tsunami Caused By Landslides
3. The Tsunami Caused By Meteorological Conditions
Rapid changes in barometric pressure, such as those seen when a front passes through, can displace bodies of water enough to cause trains of waves with wavelengths similar to seismic tsunamis, but with lower energies.
These are basically dynamically similar to seismic tsunamis, with the exception that Meteotsunami lacks the transoceanic scope of substantial seismic tsunamis and that the force that displaces the water is maintained over time, preventing Meteotsunami from being modelled as occurring instantly.
Types of Tsunami
There are three basic types of the tsunami that occur worldwide. Let us discuss in detail the types of tsunamis in this article on tsunami.
A regional tsunami is described as one that causes damage between 100 and 1,000 kilometres from the source of the tsunami. Outside the 1,000-kilometer perimeter, more contained damages will occur in some cases.
A distant tsunami, also known as a Teletsunami or ocean-wide tsunami, is caused by a strong and devastating occurrence that occurs more than 1,000 kilometres away from landfall.
Effects of Tsunami
A tsunami's impact on a coastline can vary from mild to catastrophic. The characteristics of the seismic event that caused the tsunami, its distance from its point of origin, its duration, and, finally, the structure of the depth of water in oceans along the coast that the tsunami is approaching, all influence the effects of the tsunami.
Tsunamis inflict damage by two mechanisms: the slamming force of a fast-moving wall of water, and the destructive strength of a large volume of water draining off the ground and bringing a large amount of debris with it, even with small waves.
The initial wave of a large tsunami is extremely high, but it does not cause the majority of the damage. The vast mass of water behind the initial wavefront causes the majority of the damage, as the sea level continues to rise rapidly and floods the coastal region.
Tsunami waves wreck everything in their path: boats, houses, bridges, vehicles, trees, telephone lines, power lines, and just about everything else.
If the tsunami waves have swept away the shoreline's infrastructure, they will proceed inland for several miles, sweeping away more trees, houses, vehicles, and other man-made objects.
People who live in coastal areas, cities, and villages do not have the luxury of time to flee. The tsunami's strong force causes instant death, most usually from drowning. Another cause of death is buildings collapse, electrocution, and fires from gas, broken tanks, and floating debris.
Tsunamis not only kill humans, but also wipe out insects, livestock, plants, and natural resources.
More Facts About the Tsunami
The most dangerous tsunami recorded till now is the Boxing day tsunami, also known as the Indian Ocean tsunami with at least 2,30,000 people killed or missing in 14 countries bordering the Indian Ocean, it was one of the worst natural disasters in human history.
Some zoologists claim that some animals can detect subsonic Rayleigh waves generated by an earthquake or tsunami. Monitoring their actions, if done correctly, may provide an early warning of earthquakes and tsunamis. The proof, on the other hand, is debatable and not generally accepted.
The US states like Hawaii, Alaska, Oregon, California, and Washington are at the highest risk of Tsunami.
If anyone is caught by a Tsunami wave, it’s better to not swim, instead, he must grab an object and let the wave carry him.
In 2004, an earthquake caused a tsunami in the Indian Ocean with the energy of 23000 atomic bombs. After the earthquake, 11 countries were slammed by the radiation emitted from the epicentre. The total death toll was 283000.
A Tsunami becomes dangerous when it approaches land. Its speed decreases from 30mph to 20mph when it enters shallow water near coastlines. The height increases, wavelength decreases, and the currents intensify. Tsunami warnings come in various forms. Tsunami warning centres broadcast warnings through local radio and television, weather radios, wireless emergency alerts, and social media. They may also be received by outdoor sirens, text message alerts, local officials, and telephone notifications.
It is better to recognize natural tsunami warnings instead of waiting for an official warning. These include long and strong earthquakes, a loud sound (similar to train or aeroplane) coming from the ocean, a sudden rise or fall in the sea level not related to the tide. Both natural and official warnings are equally important. One should be prepared to respond quickly to these warnings.
One can move to a safe place by following the evacuation signs. If an individual is unable to do so, then he must go to high ground or far away from the coastlines.
When tsunamis strike land, their height is less than 10 feet, but in some cases, it can exceed 100 feet near their source.
A tsunami can come to the shore like a wall of turbulent water or a fast-rising flood. Moreover, a huge tsunami wave can destroy low-lying coastal areas to a large extent.
Rushing water from floods, waves, and rivers is highly powerful. It can wash off everything coming on their way.
Tsunamis are destructive due to their volume and speed. They become more dangerous when they return from the sea carrying people, objects, and debris with them. Therefore, people are advised to stay out of the tsunami hazard zones until the conditions come under control.