Researchers break record for deep-sea drill depth

A Japanese research institute says its deep-sea drilling probe has set a new record for depth, reaching 25,400ft – almost five miles – below the Pacific Ocean's surface.

The Chikyu, operated by the Japan Agency for Marine-Earth Science and Technology, was digging the seabed off Japan's north coast to take fault samples to study last year's earthquake and tsunami.

Maritime organisations say the US vessel Glomar Challenger set the previous record of 23,130ft below sea surface in the Mariana Trench in 1978.