Scientists just dug the deepest ocean hole in history

The research vessel Kaimei cruises the Pacific Ocean near the Japan Trench.
The research vessel Kaimei cruises the Pacific Ocean near the Japan Trench. (Image credit: JAMSTEC)

A team of researchers working off the coast of Japan just drilled a hole in the Pacific seabed deeper than any hole in any ocean before it.

On May 14, scientists aboard the research vessel Kaimei lowered a long, thin drill called a giant piston corer nearly 5 miles (8,000 meters) through the Pacific Ocean — waiting two hours and 40 minutes until the drill finally reached the bottom of the Japan Trench, according to a statement. There, the team extracted a 120-foot-long (37 m) sediment core from the bottom of the sea before slowly hauling the corer up again.

The drill site is located very close to the epicenter of the magnitude-9.1 Tohoku-oki earthquake, which battered the region in 2011 and produced a gargantuan tsunami that smashed into the Fukushima Daiichi nuclear power plant, triggering a devastating meltdown. By studying sediment from this area, the researchers hope to learn more about the trench's ancient earthquake history.

This deep drilling operation blows the previous ocean drilling record holder out of the water. For nearly 50 years, that record has belonged to the research vessel Glomar Challenger, which sunk a drill into the Mariana Trench in 1978. That operation recovered a sediment core from about 4.3 miles (7,000 m) below the surface — or about 1,000 m closer to fresh air than the recent RV Kaimei expedition, the team said.

As for the deepest hole ever dug, on land or sea? That title goes to the Kola Superdeep Borehole, created by Russian scientists in the country's far northern Kola Peninsula in 1989. Drilling for the project began in 1970; nearly two decades later, the hole reached a maximum depth of 7.6 miles (12,200 m) below the surface.

The Kola project turned up many geological samples from the continental crust — but, sadly, no buried treasure. No big loss, in the end; sometimes in Siberia, gold just falls from the sky.

Originally published on Live Science.

Brandon Specktor

Brandon is the space/physics editor at Live Science. His writing has appeared in The Washington Post, Reader's Digest,, the Richard Dawkins Foundation website and other outlets. He holds a bachelor's degree in creative writing from the University of Arizona, with minors in journalism and media arts. He enjoys writing most about space, geoscience and the mysteries of the universe.