Dinosaur-killing asteroid impact triggered months-long ‘megaquake’, research shows

The catastrophic asteroid impact that killed the dinosaurs may have caused a powerful ‘mega-quake’ that shook the Earth for months.

66 million years ago a massive Solar System body—now known as asteroid Chicxulub—collided with Earth, excavating a massive 180 km long. (110 miles) wide impact crater in what would later become the Yucatan Peninsula.

This collision set off a chain of cataclysmic events which, when combined with the devastation caused by the initial impact, wiped out 75 percent of all life on Earth.

Now, new research analyzing geological records from this traumatic period in our planet’s history has revealed that the devastating impact may have caused a “megaquake” that lasted for weeks or even months before subsiding.

The research was presented Oct. 9 at the annual meeting of the Geological Society of America by Hermann Bermúdez of Montclair State University – one of the scientists who worked on the study.

In 2014, Bermúdez discovered a series of tiny glass spheres and fragments, about 1 millimeter in size, buried among the sediment on Gorgonilla Island, which is off the west coast of Colombia.

These tiny remnants formed the day the Chicxulub asteroid hit the surface. The impact threw massive amounts of molten material high into the atmosphere, which then coalesced, cooled, and fell back to Earth as glassy balls and irregularly shaped debris.

At the time the asteroid hit, the site Bermúdez had excavated was actually underwater. Despite being about 3,000 km (1,860 mi) from the impact site, the undersea landscape was distorted by the force of the event. Traces of this deformation — which extended 10 – 15 meters (30 – 50 feet) underground — are still visible to this day.

Bermúdez and his co-researchers also recorded faults, fissures and evidence of a process called liquefaction — where water-saturated sediments flow freely like water under the shaking effect of an earthquake — in Mexico and the United States.

According to a press release from the Geological Society of America (GSA) describing the presentation, the earthquake that shook the Earth in the wake of the extinction event was about 50,000 times stronger than the magnitude 9.1 earthquake that devastated Sumatra in 2004 .

The researchers found that the disturbance caused by the shaking extended through the sediment layer from where the asteroid hit to where the team found the tiny glass spheres on Gorgonilla Island.

Geological evidence suggests that the super-quake must have endured for weeks, or even months, for the debris ejected from the impact to descend into the atmosphere, then into the ocean environment, to settle on the sea floor. .

Just above this layer, the team discovered spores from the ferns, which indicated that the environment had settled enough at this point to allow plant life to re-establish itself.

The damage caused by the earthquake would have added to the destruction caused by the powerful tsunamis and atmospheric debris flows that the event caused.

NASA and its partners recently completed the world’s first planetary defense mission – the Dual Asteroid Redirect Test (DART) — in which a spacecraft crashed into the surface of a distant asteroid in an attempt to change its orbital path.

The agency hopes this mission is the first step on the road to developing an effective strategy that could one day save our race—and all life on Earth—from the dangers of another potentially devastating asteroid strike.

Check out IGN’s science page to keep up with the biggest and weirdest developments in the world of science.

Anthony Wood is a freelance science writer for IGN

Image source: Vadim Sadovski

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