Scientists Drill a Mile Into Active Deep Sea Fault Zone

From Wired Science:

In the first deep sea drilling expedition designed to gather seismic data, scientists have successfully drilled nearly a mile beneath the ocean floor into one of the world’s most active earthquake zones.

Researchers aboard the drilling vessel Chikyu — meaning “planet Earth” in Japanese — used a special technology called riser drilling to penetrate the upper portion of the Nankai Trough, an earthquake zone located about 36 miles southeast of Japan. By collecting rock samples and installing long-term monitoring devices, the geologists hope to understand how stress builds up in subduction zones like Nankai, where the Philippine Sea plate plate is sliding beneath the island of Japan.

Riser drilling involves encasing a deep sea drill in a giant metal tube, called a riser, that extends from the ship down to the drilling site, effectively bolting the ship to the sea floor. The researchers circulate lightly pressurized mud down through the drilling tube and back up through the riser.

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