A tsunami is essentially an earthquake that originates at sea level. Depending on its magnitude and location, it may or may not trigger a tsunami. In other words, not all tsunamis produce tsunamis, but all tsunamis are caused by tsunamis. However, before explaining about real-life giant tsunamis , let's take a look at how this natural phenomenon is created.
How does a tsunami originate?
Just like an earthquake, a tsunami originates from the movement at the boundary of two tectonic plates. The hypocenter, also called the epicenter of the tsunami, is the point where the movement or separation of the tectonic plates tends to occur. This natural phenomenon has been studied in relation to natural disasters and is linked to the impact of events such as the eruption of Krakatoa in 1883.
The intensity of a tsunami is determined by a complex series of variables, but the essential factor is the type of geological fault that determines the alignment of the tectonic plates. In this context, the moment vertical movement occurs between the plates, the water level rises and the wave is created.
On the other hand, it's important to note that when a sufficiently strong earthquake occurs, with its hypocenter located relatively close to land, the rise in water level is seen as a retreat of the shoreline . If you are on the beach when a tsunami occurs, you will notice the shoreline beginning to recede, indicating the formation of a tsunami. The height of the wave and its speed clearly depend on the strength of the earthquake that triggered it.
A prime example of a real-life giant tsunami is the one that occurred in 2004 in the Indian Ocean, which registered a magnitude of 9,0 Mw on the instantaneous magnitude scale (a scale with greater force than the Richter scale). It originated 120 kilometers off the coast of Sumatra and approximately 30 kilometers below sea level. For more information on natural disasters, you can visit this related article. You can also consult research on the history of the planet, which can provide additional context on natural events such as the extinction of the dinosaurs.
Time that one of the real giant tidal waves lasted
The earthquake that originated at the time of the tsunami lasted from 8 to 10 minutes. It produced a series of tsunamis that traveled across the Indian Ocean for a few hours. However, the first wave, which had a height of 15 meters, shook the coast of Sumatra in just a few minutes.
As I've already mentioned, a tsunami is similar to an earthquake but occurs deep in the ocean. If it's a low-intensity tsunami, it might not even be visible on the surface and won't create waves large enough to be considered a tsunami. However, if it's more intense, like real giant tsunamis, and occurs close to the coast, a tsunami is one of the most catastrophic natural disasters that can happen.
Classification of tsunamis
Tsunamis can be classified according to various factors.
production origin
The following will explain those that are given according to their origin of production.
1. Tectonic Tidal Wave
For a tsunami to occur, the seabed must be disturbed vertically , causing a large accumulation of water to be displaced from its normal equilibrium. As I mentioned earlier, not all earthquakes on the ocean floor produce tsunamis; only those of significant magnitude and relatively low depth generate them. The Pacific Ocean is the area most affected by this type of tsunami because it contains the most active region on our planet and is also prone to major natural disasters.
2. Tidal waves by volcanoes
These occur due to underwater eruptions. The process in an underwater eruption is the same as in an eruption on land, causing earthquakes and a massive explosion that is the primary beginning of tectonic movement and the flow of the Earth's mantle . The impact caused by the collision of the layers in a vertical position with little depression rapidly forms the giant wave that travels at an average speed of 400 km/h. You can find more information about the history of the planet in this related article.
3. Tidal waves due to land movement
As we often find in the depths of the sea, there are some landforms that are similar to those on the surface; that is, we can find mountains, rocks, plains, and so on. These underwater landforms produce a surge of energy that explodes as waves, creating them on a gigantic scale.
4. Submarine burst tsunamis
These waves originate from natural explosions caused by pressure or from past wars, creating formidable waves. These explosions require a certain degree of nuclear force to generate the necessary power to create an enormous wave of such magnitude that it impacts nearby beaches.
Birthplace
Another way in which tsunamis can be classified is according to their place of origin.
1. Local tsunamis
Local tsunamis are the most powerful . Based on verified data from some coastlines, the first wave can occur between 10 and 30 minutes after the earthquake. Identifying these characteristics is crucial for evacuation planning, as it provides the necessary time to evacuate the population from the affected region.
2. Regional tsunamis
This type of tsunami occurs if the place where the wave will fall is about 1000 km from the spawning zone.
3. Distant Tsunamis
If the arrival point is on beaches facing the extreme or opposite side of the Pacific Ocean , at a distance of 1000 km from the generation zone, it will take approximately half a day or more for the tsunami to affect a population.
Frequently asked questions about tidal waves and their relationship with tsunamis
Many people tend to ask themselves repeatedly, what causes a tsunami? Do all earthquakes that occur at sea produce tsunamis? And what was the most intense tsunami ever recorded?
According to these questions, scientist Goff points out that anything that disturbs the ocean floor has the potential to produce a tsunami . In other words, all the primary causes we've heard about originate from underwater earthquakes, as well as submarine eruptions , nuclear weapons tests, and even asteroids falling into the sea. Furthermore, the 1883 eruption of Krakatoa also left a significant mark on tsunami history.
On the other hand, underwater volcanoes are also capable of releasing massive tsunamis, as exemplified by the 1883 eruption of Krakatoa, which generated a wave 30 meters high. Similarly, the scientist points out that people tend to underestimate the impact of tsunamis on the ground, both underwater and above water.
Finally, he indicates that among the real giant tsunamis that have been recorded so far and that are associated with the appearance of a tsunami is the one that took place in 1958 in Alaska and where a wave of 530 meters in height was generated.
