A JAPANESE research ship has drilled a 1.6-kilometre-deep hole in the sea floor while floating on 2 kilometres of ocean 鈥� making it the deepest hole ever drilled from a ship.
The , operated by the Japan Agency for Marine-Earth Science and Technology, uses a technique known as riser-drilling, which recirculates viscous 鈥渄rilling mud鈥� to maintain pressure balance in the borehole.
According to of the United States Geological Survey in Menlo Park, California, petroleum drilling on land and from stable ocean platforms regularly reaches depths of between 5 and 8 kilometres. The deepest land-based hole, drilled for research purposes on the Kola peninsula in Russia, goes down more than 12 kilometres, but drilling from a ship is a different matter, he says.
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Nancy Light of the in Washington DC, which coordinates research drilling projects like Chikyu, says that the new vessel is designed to drill to depths of 12 kilometres beneath the sea floor, while floating on very deep, sometimes tumultuous, seas.
The team aims to put pressure and temperature sensors in the borehole to collect signals that may one day help predict earthquakes. The hole is in the subduction zone created by the Philippine plate slipping beneath the Eurasian plate, a geological process that periodically unleashes massive earthquakes and large tsunamis.