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Seismometer takes on sea’s deepest quakes

Kyodo

The Japan Agency for Marine-Earth Science and Technology has developed an undersea seismometer that works at depths of more than 10,000 meters, allowing it practically to observe undersea quakes in all waters.

The government-backed agency said it has installed the instrument at seven places deeper than 6,000 meters — the limit for conventional seismometers — in the Japan Trench, and collected data during an experiment in December and January using the deep-sea probe ship Kairei.

The device is protected by a round ceramic container roughly 44 cm in diameter that is designed to go as deep as 11,000 meters without breaking, the agency said.

Detailed observations around the focus of quakes are necessary to analyze the mechanisms that drive major temblors.

In the March 11, 2011, quake that struck off the Tohoku coast, existing seismographs were of no use because the trench in the area was deeper than 6,000 meters.