How Big Were Ancient Tsunamis? Paleotsunami Researchers Examine Olden Disasters

Knowing more about ancient tsunamis is a vital exploration for scientists. This is because if huge and destructive tsunamis happened in a specific place before, they could happen again. The matter lies in whether people are prepared for such a devastating event.

Previously Undocumented Paleotsunami

According to Hakai Magazine, a huge boulder with a weight of over 40 tons can be found along the Chilean shores. Its presence makes every other rock appear like a dwarf. Why such a boulder ended up in such a place is not because of the Atacama Desert at its back but because of the Pacific Ocean.

Over hundreds of years ago, a strong tsunami hit the shores of northern Chile. It formed a water wall that had a height of 20 meters and swept weighty boulders as if they were mere, puny pebbles.

Hakai Magazine reports that this tsunami took place before Chilean written documents existed. However, such a paleotsunami was discovered because of the research efforts of paleotsunami researchers. With various scientific methodologies, the researchers were able to discover evidence that a previously undocumented colossal tsunami took place. As they progress, their findings also show how coastal areas could be more prone to danger than they think.

The implications of the study are quite simple. If such paleotsunamis took place in that area before, they can still happen again.

Tsunami vs. Big Waves: What's the Difference?

While it may sound like a huge wave, a tsunami is more than that. Typical waves, even those that reach a height of 10 meters, are usually facilitated by the wind and only cover the topmost water layers. They have minimal energy and usually harmlessly hit the coast.

On the other hand, tsunamis result from geological events, be they a volcanic eruption, earthquake, or mountain chunks falling into the ocean. The whole column of water gets involved in a tsunami.

The Atlantic reports that though tsunamis can go over 20 meters high, even those that aren't extraordinarily high can lead to great damage. Rather than simply hitting the shores, tsunamis rush forward. After they reach far inland, the water starts receding. As this happens, the water carries virtually anything that is within its path.

Tsunamis often leave marks of their attacks, such as outlier boulders.

Pursuit of Paleotsunamis

Paleotsunami researcher James Goff, from the University of Southampton, has been looking for paleotsunamis for nearly 30 years. He mostly focused on areas around the Pacific Ocean.

According to Goff, the easiest way to tell whether a tsunami took place thousands or hundreds of years ago is to look below the surface. As tsunami waves recede, they leave behind marks on the surface. Layers of shells, rocks, silt, and other deposits get buried as time passes, which leads to the preservation of the disaster's path. In certain areas, these layers are preserved so well that evidence of several tsunamis gets stacked over each other.

Across southern Chile, one may simply dig close to coastal areas and count the present bands. Examining such layers can reveal paleotsunamis.

However, in barren or rockier areas, detection is quite trickier. Methodologies used must match the environment. Goff and other scientists search for foraminifera, diatoms, geochemistry changes, ancient marine DNA, and boulders.

They may also look into archaeological records and additional evidence.

While discovering the size and impact of the paleotsunami could be a historical interest matter, findings may help modern communities by the shores. While predicting such events is not possible, paleotsunami researchers show that the previously unknown tsunamis could have been even worse than the ones that are known. Though they may have taken place thousands of years before and such areas may not have seen any colossal waves, people should expect them to hit sometime and somewhere.

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