Asteroid that wiped out the dinosaurs also triggered a global tsunami

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When a city-size asteroid slammed into Earth 66 million years ago, it wiped out the dinosaurs – and sent a monster tsunami rippling around the planet, according to new research.

The asteroid, about 8.7 miles (14 kilometers) wide, left an impact crater about 62 miles (100 kilometers) across near Mexico’s Yucatan peninsula. In addition to ending the reign of the dinosaurs, the direct hit triggered a mass extinction of 75% of animal and plant life on the planet.

When the asteroid hit, it created a series of cataclysmic events. Global temperatures fluctuated; plumes of aerosol, soot and dust filled the air; and wildfires started as flaming pieces of material blasted from the impact re-entered the atmosphere and rained down. Within 48 hours, a tsunami had circled the globe – and it was thousands of times more energetic than modern tsunamis caused by earthquakes.

Researchers set out to gain a better understanding of the tsunami and its reach through modeling. They found evidence to support their findings about the path and power of the tsunami by studying 120 ocean sediment cores from across the globe. A study detailing the findings published Tuesday in the journal American Geophysical Union Advances.

It’s the first global simulation of the tsunami caused by the Chicxulub impact to be published in a peer-reviewed scientific journal, according to the authors.

The tsunami was powerful enough to create towering waves more than a mile high and scour the ocean floor thousands of miles away from where the asteroid hit, according to the study. It effectively wiped away the sediment record of what happened before the event, as well as during it.

“This tsunami was strong enough to disturb and erode sediments in ocean basins halfway around the globe, leaving either a gap in the sedimentary records or a jumble of older sediments,” said lead author Molly Range, who began working on the study as an undergraduate student and completed it for her master’s thesis at the University of Michigan.

Researchers estimate that the tsunami was up to 30,000 times more energetic than the December 26, 2004 Indian Ocean tsunami, one of the largest on record, that killed more than 230,000 people. The energy of the asteroid impact was at least 100,000 times larger than the Tonga volcanic eruption earlier this year.

Brandon Johnson, study coauthor and an associate professor at Purdue University, used a large computer program called a hydrocode to simulate the first 10 minutes of the Chicxulub impact, including the formation of the crater and the beginning of the tsunami.

He included the size of the asteroid and its speed, which was estimated to be moving at 26,843 miles per hour (43,200 kilometers per hour) when it hit the granite crust and shallow waters of the Yucatan peninsula.

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