Catastrophic, Prehistoric Landslide was the Largest on Earth

A catastrophic landslide that occurred 21 million years ago may be the largest to have ever occurred on Earth's surface. Scientists have discovered the remains of the Markagunt gravity slide, which was the size of three Ohio counties.

Geologists have known about smaller portions of the Markagunt slide for years. Yet recent mapping techniques have finally shown its full extent. Now, researchers have announced that this landslide was far, far larger than previously expected.

The landslide itself occurred in an area between what is now Bryce Canyon National Park and the town of Beaver, Utah. It covered a staggering 1,300 square miles, and was probably far larger than the Heart Mountain slide.

"Large-scale catastrophic collapses of volcanic fields such as these are rare but represent the largest known landslides on the surface of Earth," wrote the authors in a news release.

What's more interesting is that this landslide wasn't just huge; it was also fast moving. The length of the landslide-55 miles-shows that it sped along at a rapid clip. Additional evidence shows that the landslide itself happened within minutes; rocks were actually melted into glass by the immense friction that the landslide caused, and any animals in its path would have been quickly overrun.

So what caused the landslide in the first place? The collapse could have been caused by the vertical inflation of deeper magma chambers that fed volcanoes. That said, the research is still ongoing.

"We study events from the geologic past to better understand what could happen in the future," said David Hacker, one of the researchers, in a news release.

Currently, the scientists plan to continue mapping the slide and collect samples from the base for structural analysis.

The findings are published in the journal Geology.