Nearly all the dinosaurs and around three-quarters of all the planets and animals on Earth were wiped out by a kilometres wide asteroid that struck the planet 66 million years ago. According to a new study, the asteroid also triggered a massive tsunami that scoured the ocean floor thousands of kilometres away from the impact site on the Yucatan Peninsula.
The study published in the journal AGU Advances simulated the Chicxulub impact and its effects. Further, the researchers reviewed geological records of more than 100 sites around the world and found evidence that supports the model’s predictions about the tsunami’s strength and path.
“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, in a press statement. Range conducted the modelling study for a master’s thesis at the University of Michigan.
The authors estimate that the initial energy in the impact tsunami was as much as 30,000 times higher than in the December 2004 Indian Ocean tsunami, which killed over 2,30,000 people.
For the study, the researchers focused on “boundary sections” or marine sediments deposited just before or after the asteroid impact and the extinction that followed it. “The distribution of the erosion and hiatuses that we observed in the uppermost Cretaceous marine sediments are consistent with our model results, which gives us more confidence in the model predictions,” said Range.
For the modelling, researchers used a computer program called a hydrocode to simulate the first ten minutes of the event. This included the impact, crater formation and initiation of the tsunami. Based on previous research studies, the researchers modelled an asteroid with a 14-kilometre diameter moving at a speed of 12 kilometres per second.
The model showed that two and a half minutes after the asteroid strike, a curtain of ejected materials caused the brief formation of a 4.5-kilometre high wave that subsided after the materials fell back to the Earth. Ten minutes after the asteroid struck, a 1.5-kilometre-high tsunami began sweeping across the ocean in all directions. The results of the hydrocode simulations were then entered into two different tsunami propagation models.
“The big result here is that two global models with differing formulations gave almost identical results, and the geologic data on complete and incomplete sections are consistent with those results. The models and the verification data match nicely.” co-author Ted Moore said in a press statement. Moore is professor emeritus of earth and environmental sciences at the University of Michigan.
The researchers have planned a follow-up study to model how this tsunami flooded coastal regions across the world.