The asteroid that killed the dinosaurs drove a 100-meter tsunami thousands of kilometers

When the The Chicxulub impact meteor hit the planet, 66 million years ago, a tsunami of enormous proportions was formed. Now scientists are studying what the phenomenon would have been like, collecting samples in the seas and running simulations of the first few minutes after the impact, which occurred near the Yucatan Peninsula, in Mexico, and the effects that followed.

According to the scientists, the giant wave was strong enough to lift ocean basins over about half of the planet, leaving a hole in sedimentary records or mixing older sediments. For the study, border sedimentary areas were analyzed, i.e. places where marine sediments were deposited before or immediately after the impact and extinction of K-Pg (Cretaceous-Paleogene), which can also be observed with the naked eye due to the difference of iridium brought by the asteroid.

Photo: Unsplash / Matt Paul Catalano / Canaltech

Sediments, oceans and tsunamis

It is estimated that the energy of tsunami caused by the impact was 30,000 times greater than that of the 2004 Indian Ocean tsunami, which killed 23,000 people and was one of the largest waves of the contemporary era. 66 million years ago, the tsunami would have reached the north of the Atlantic Ocean, passing through the Central American channel (which at the time separated the Americas) and the South Pacific.

In these regions, the sea current probably exceeded 20 centimeters per second, enough to erode the finer sediments from the seafloor. In the South Atlantic, in the North Pacific, in the Indian Ocean and in the present Mediterranean, the effects of the tsunami did not arrive as strongly, according to the simulations: no more than 20 cm / sec.

The study analyzed the records of 164 marine sedimentary boundary areas, gathering useful information from 120 of them. In the most affected areas, the K-Pg boundary is less clear: in New Zealand, more than 12,000 km from the impact, the sediments are incomplete and heavily overturned, which is consistent with the expected path for the tsunami. In the Indian Ocean and the Mediterranean, the border is clearer and more complete, proving to have been saved from impacts.

Watch the video of the simulation:

& nbsp;

Based on other studies, a Asteroid of 14 km in diameter, with a speed of 12 km / s. In the simulation, the fireball collided with a granite crust covered with thick sediment in shallow ocean waters, generating a crater about 100 km wide and expelling dense clouds of soot and dust into the atmosphere.

Two and a half minutes after impact, a curtain of material pushed a wall of water out of the impact, forming a short-lived 4.5km-high wave, which dispersed after the ejections hit Earth. . In the next 10 minutes – and 220km from impact – a tsunami of 1.5 km began to spread in a ring, outwards and in all directions. Methods and models were used currently predict deep tsunamis.

Two global models with different formulas gave nearly identical results, showing how complete, reliable and consistent the data was even in sections with incomplete data. Continuing with the results, the team estimated that, 1 hour after the impact, the tsunami had already spread beyond the Gulf of Mexico to the North Atlantic.

About 4 hours after the impact, the waves would have passed the Central American channel, reaching the Pacific. After 24 hours, the waves would cross most of the Pacific to the east and most of the Atlantic to the west, entering the Indian Ocean on both sides. Within 48 hours, the tsunami waves would have reached most of the world’s coasts.

The study did not assess the level of coastal flooding caused by the tsunami, which should be done in a future, already planned survey. However, the models indicated the size of some waves: in the Gulf of Mexico they would have reached 100 meters in height, with more than 10 meters in the North Atlantic and in some parts of the Pacific, on the South American coast. Once they reached the coastal region, they would increase, in a phenomenon called wave blistering. In these regions the speed would have reached 20 m / s.

Source: AGU advances

Trend no Canaltech:

+The best content in your email for free. Choose your favorite Earth Newsletter. Click here!

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.