The 14-kilometer-wide Chicxulub asteroid responsible for the mass extinction of the dinosaurs caused a gigantic global tsunami, much larger than what we know from modern history.
The meteor that killed all dinosaurs 65 million years ago caused a one-and-a-half-mile tsunami when it hit the Gulf of Mexico.
The First Moments After Impact
To make accurate estimates of the size of the tsunami, the researchers used a computer model that could calculate the large-scale deformation of the Earth’s crust and the chaotic waves caused directly by the impact and the recoil of the water in the formed crater.
That model detailed the events in the first ten minutes after the asteroid’s impact: the impact crater — initially 1.5 kilometers deep — did not contain any water at the time. That was blown away by the force of the impact. The water then ran into the crater, creating a collapsing wave and flowing out again.
The Biggest Tsunami In History
Based on data about the sea level and the speed of the water, the researchers then calculated how that tsunami moved over all the world’s oceans. The US researchers’ findings are also supported by geological evidence: the tsunami caused erosion and displacement of sediments that are still measurable today.
In the Gulf of Mexico, the wave was a mile high, moving at 143 km/h. Then the water spread to the Atlantic Ocean, and — via the Central American Seaway, which no longer exists today — also to the Pacific Ocean. At that point, the size of the wave had diminished to 14 meters.
By comparison, the largest wave in modern history was barely 23.8 meters high.
According to the researchers, a comparison with the tsunami in the Indian Ocean that claimed 225,000 lives in 2004 is also impossible. They were as different as night and day.
In the first 7 hours of both tsunamis, the Chicxulub’s impact was 2,500 to 29,000 times greater than the 2004 tsunami.
As severe as the effects of the tsunami were, it was not the only cause of the extinction of the dinosaurs. The asteroid’s impact also released a massive amount of particulate matter into the atmosphere, burning animals alive and setting wildfires.
That dust also blocked the sunlight on earth for years, so that plant growth and the entire food chain were disrupted.
The Chicxulubcrater
Chicxulub Crater is the 180-kilometer-wide remnant of an asteroid impact that occurred about 65 million years ago. The crater was discovered in 1991. Its impact probably led to the end of the age of the dinosaurs.
The crater had gone undetected for decades as it was hidden by 1000 meters of younger rocks. As a result, there is not much to see on the surface today except for the ring of underground pools that line the old crater rim.
The crater was eventually found because geological research revealed anomalies in the gravitational field, among other things.
In the Cretaceous-Tertiary transition, almost all larger animal species became extinct, including the dinosaurs.
Originally Published on Medium by me (Bryan Dijkhuizen)
Resources & References
- https://geology.com/records/biggest-tsunami.shtml#:~:text=A%20tsunami%20with%20a%20record,occurred%20in%20Lituya%20Bay,%20Alaska&text=On%20the%20night%20of%20July,northeastern%20shore%20of%20Lituya%20Bay
- https://lsa.umich.edu/earth/news-events/all-news/search-news/earth-ms-student-molly-range-featured-in-eos.html
- https://en.wikipedia.org/wiki/Chicxulub_crater
