If, or perhaps when, an asteroid strikes the Earth, it will likely end up in Davy Jones’ locker.
Our planet’s surface is 70 percent water by area, and an aquatic impact would create a sizable tidal wave that could do some serious damage if it hits a populated area. But apocalyptic visions of the devastation resulting from an asteroid strike may be slightly overblown, say scientists at the Los Alamos National Laboratory.
The team used a supercomputer-assisted model to simulate the outcomes of various types of impacts, creating a series of visualizations depicting the aftermath. Along with the size of the rock and angle of impact, the biggest factor in determining the potential for destruction is whether the asteroid breaks up before hitting the surface, or what’s called an “airburst.”
Breaking up before smacking Earth would spread the asteroid’s impact across a wider area, reducing the size of the splashdown and the waves that it would generate.
Even if an intact asteroid does hit the surface, the waves it creates will spread outward in an ever-widening circle, like massive versions of the rings formed by dropping a pebble into a pond. While they could still be dangerous, these circular disturbances wouldn’t be as powerful as the line waves created by earthquakes and underwater landslides.
The researchers say they would probably only be as strong as the waves generated by tropical storms. If an asteroid hit within 10 or so miles of a populated area, though, that’s a different story. The waves may dissipate quickly, but they would still be large enough to wreak some Hollywood-size havoc.
The researchers presented a paper detailing their findings this week at the meeting of the American Geophysical Union.
The more salient danger from an asteroid hitting the ocean would probably be the massive plume of water shooting into the air, the researchers say. Depending on the rock’s size, as much as 250 megatons of water could be forced into the atmosphere. Some would fall back quickly, but enough would be vaporized that clouds of water would hang around in the stratosphere for months or even years.
Water vapor traps heat on Earth, making it a powerful greenhouse gas. Instead of city-leveling tsunamis, our biggest worry from an asteroid impact might be getting cooked.