In addition to helping to gather details on the demise of the dinosaurs, the researchers say the findings provide insight into late Cretaceous geology.
“This is a global tsunami,” said Molly Ring, a University of Michigan scientist and co-author of the study. “The whole world is seeing this.”
After the asteroid impact, there will be an extreme rise in water level in two phases, the team found: the edge wave and the resulting tsunami wave.
“If you drop a stone into a puddle, that’s where the starting point is,” Rang said.
These boundary waves may have reached an unimaginable height of a mile – and that was before the tsunami actually started, according to the newspaper’s estimates.
“Then you see the wedge effect with the water being expelled symmetrically [from the impact site]Ring said, noting that the Chicxulub asteroid hit the northern Gulf of Mexico in what is now the Yucatan Peninsula.
After the first 10 minutes after the collision, all the airborne debris associated with the asteroid had stopped falling into the bay and displacing the water.
“It was pretty calm and a crater formed,” Rang said. It was then that the tsunami began to ply the ocean at the speed of a commercial jet.
“The continent looks a bit different,” Rang said. “Most of the east coast of North America and the north coast of Africa easily saw waves over 8 meters high. There is no land between North and South America, so the waves are directed towards the Pacific Ocean. “
Ring likened the incident to the infamous 2004 Sumatran tsunami following a 9.2 magnitude earthquake off the west coast of north Sumatra. More than 200,000 people died.
More than 60 million years ago, Ring said, a megatsunami had 30,000 times more energy than in 2004.
To simulate a megatsunami, a team of scientists used plumbing code, a 3D computer program that models the behavior of fluids. The hydrocoding program works by digitally dividing the system into a series of small Lego-like blocks and then calculating the forces acting on them in three dimensions.
The researchers drew on previous studies and hypothesized that the meteorite was 8.7 miles in diameter and a density of about 165 pounds per cubic foot, roughly the average weight of a male tucked into a volume the size of one. milk case. This means that the entire asteroid probably weighed about 2 quadrillion pounds, or 2 followed by 15 zeros.
After the hydraulic code generated an initial simulation of the impact and the first 10 minutes of the tsunami, the modeling was converted into a pair of models developed by the National Oceanic and Atmospheric Administration (NOAA) to address the spread of tsunamis in global oceans. . The first is called MOM6.
“We initially started using the MOM6 model which is a multipurpose marine model, not just a tsunami model,” said Ring. The team was forced to speculate about the bathymetry, or the shape and slope of the ocean floor, as well as the depths of the ocean and the structure of asteroid craters. This information, along with the tsunami waveform from the water blade model, was injected into MOM6.
In addition to building models, the study researchers examine the geological evidence to study the tsunami’s direction and strength.
Range co-author Ted Moore found evidence of significant disturbance of sediment layers in marine and coastal highlands at more than 100 sites, supporting the study model simulation results.
The modeling estimates a tsunami flow velocity of 20 cm per second on most beaches in the world, more than enough to disturb and erode sediments.
The researchers say the geological findings add confidence to their simulation model.
In the future, the team hopes to learn more about the extent of the flood that accompanied the tsunami.
“We want to see flooding, which we haven’t done with just the current job,” Ring said. “You really need to know bathymetry and topography.”
