Find out all about this tsunami over 1,600 meters high!

tsunami
The Upper Cretaceous asteroid caused a massive global tsunami, reaching a maximum height of 1,600 meters. Image by PXHER for illustration only

A global and devastating tsunami

According to a new study, the asteroid that struck Earth and caused the Cretaceous-Paleogene (K-Pg) mass extinction 66 million years ago also triggered a global tsunami which began as a wave over 1,600 meters high. The tsunami was large enough to cross the ocean floor thousands of miles from the site of impact on the Yucatan Peninsula in Mexico.

The study, published in AGU Advances, presents the world’s first tsunami simulation of the Chicxulub impact to be published in a scientific journal peer-reviewed, corroborated by a comprehensive new compilation of geological sites containing evidence of a massive global tsunami.

Recovery from the aforementioned impact

Their models indicate that the height of the waves in the open sea in the Gulf of Mexico would have exceeded 300 meters (984 feet) approximately one hour after impact.

Maximum wave heights generally decrease with time and distance from impact. The authors calculated that the initial energy of the tsunami was up to 30,000 times greater than that of the December 2004 earthquake in the Indian Ocean, which is one of the largest tsunamis in modern history. According to the models, the tsunami would have dissipated in less than a week.

“Any historically documented tsunami pales in comparison to such a global impact,” the authors wrote.

To check their models against geological evidence, the authors examined 120 geological sites before and after the asteroid impact and found evidence of a global tsunami, which reached present-day New Zealand. They compared these sediments with the waves and erosion predicted by their models.

“This tsunami was powerful enough to disrupt and erode sediment in ocean basins on the other side of the world, leaving a void in the sedimentary record or a tangle of older sediment,” said lead author Molly Range, a physical oceanographer at the University of Michigan. “The distribution of erosion and hiatuses we observed in Late Cretaceous marine sediments are consistent with our model results, which gives us more confidence in the model’s predictions.”

“The geological evidence definitely strengthens the paper,” said Brian Arbic, a physical oceanographer at the University of Michigan and co-author of the study.

According to the authors, the K-Pg boundary outcrops on the eastern coasts of New Zealand’s North and South Islands, located more than 12,000 kilometers from the Yucatan impact site, are particularly prominent.

The heavily disturbed New Zealand sediments were originally thought to be the result of local tectonic activity. But given the age of the deposits and their location directly in the modeled tsunami path of the Chicxulub impact, the team suspected a different origin.

“We believe these deposits record the effects of the impact tsunami, and this is perhaps the strongest confirmation of the global significance of this event,” Range said.

Although the study did not explicitly model coastal flooding, wave heights could have reached over 10 meters (32.8 ft) as the tsunami approached coastal regions of the North Atlantic and parts of the Pacific coast of South America. North Atlantic coastal regions and parts of the Pacific coast of South America.

When the tsunami approached these shores and encountered shallow bottom waters, the height of the waves must have increased considerably by a process called “shoaling”. Such heights may well have caused substantial flooding, and future study by some of the study authors will explore this process.

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