Asteroid That Killed the Dinosaurs Also Triggered Global Tsunami

The asteroid that struck Earth 66 million years ago, wiping out three-quarters of the planet's plant and animal life (most famously the dinosaurs), also triggered a worldwide tsunami with mile-high waves. Space.com reports: A new study led by University of Michigan scientists reveals that this tsunami scoured the ocean floor and left geologic traces as far away as New Zealand -- thousands of miles away from the impact site off what's now Mexico's Yucatan Peninsula. The findings come from the first simulation that models the global effects of the impact of the massive asteroid -- named the Chicxulub impactor -- upon Earth to reach publication. The team took findings from previous research and modeled the asteroid as an 8.7-mile-wide (14 kilometers) body traveling at 27,000 mph (43,000 kph). The researchers supported the computer modeling by investigating the geological record at 100 sites across the globe. In particular, the scientists looked at "boundary sections," which are marine sediments laid down just before and just after the Chicxulub impact and the mass extinction that ended the era of our planet called the Cretaceous period. This investigation supported the predictions the model had made regarding the path and power of the Chicxulub-generated tsunami. Some of the most significant geological evidence found by the team was located 7,500 miles (12,000 km) away from the Chicxulub crater on the eastern shores of islands to the north and south of New Zealand. Here the scientists found heavily disturbed sediments called olistostromal deposits that were previously believed to be the result of local tectonic activity. [The researchers] found, however, that the age and location of these deposits put them directly in the path the team modeled for the Chicxulub-triggered tsunami. The team calculated the initial energy of the impact tsunami, finding that it was as much as 30,000 times greater than the energy of the 2004 tsunami generated by an Indian Ocean earthquake. The event, one of the largest tsunamis in modern history, killed more than 230,000 people. [...] The simulation showed that 24 hours after the Chicxulub impactor had struck Earth, waves it launched had traveled almost the full extent of the Pacific and Atlantic Oceans and had just entered the Indian Ocean from both sides. Two days after the impact, tsunami waves had hit most of the world's coastlines. The team didn't estimate how much flooding these tsunami waves would have caused, but they did calculate wave heights in the majorly impacted regions. The simulations indicated that waves in the open ocean of the Gulf of Mexico would have been over 330 feet (100 meters) high. Meanwhile, waves in North Atlantic coastal regions and parts of South America's Pacific coast would have been 10 times smaller, at around 33 feet (10 m) high. As the tsunami waves approached shorelines in these regions and hit shallow waters, however, they would have soared dramatically in height again. The findings were published in the journal AGU Advances.

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