IODP3 Expedition 503
Hadal Trench Tsunamigenic Slip History - Buried in Trench
Period: From 24 November to 12 December 2025
IODP3 Expedition 503
Hadal Trench Tsunamigenic Slip History - Buried in Trench
Period: From 24 November to 12 December 2025

Scientific Objectives
Hadal trenches are the deepest places in the ocean, where one tectonic plate slips beneath another, generating powerful earthquakes that can trigger devastating tsunamis. By drilling into these remote seafloor basins to recover sediments buried for thousands of years—samples no one has ever accessed before—we are uncovering the hidden long-term history of giant earthquakes and exploring how these extreme events shape deep-sea ecosystems and drive biogeochemical cycles of carbon and other critical elements in our Earth system. Our targets are:

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Uncover the hidden history of earthquakes and tsunamis in Japan Trench, by drilling into one of the deepest parts of the World´s ocean.

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Understand how and when giant earthquakes struck in the past.

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Evaluate the influence of earthquake-induced fluid migration (discharge) in trench-fill sediments.

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Learn how massive earthquakes impact Earth’s carbon cycle and deep-sea life, by recovering never-before-seen deep-sea sediments

Science Plan and Operation overview
We could get core samples to 178 m below seafloor by Hydraulic Piston Coring System at site C0028 (five holes: A, B, C, D and E).
The drilling at a depth of 7,608.5 meters in borehole C0028E represents the deepest drilling operation using drill pipes in the scientific drilling history, which surpassing the previous record of 7,034 meters set by the US scientific drilling vessel Glomar Challenger in the Mariana Trench in 1978.
Press release is here
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