Second Call to Participate: Expedition 503: Hadal Trench Tsunamigenic Slip History

Second Call to Participate in IODP³ Expedition 503: Hadal Trench Tsunamigenic Slip History now open!

IODP³ Expedition 503 aimed to recover the complete trench-fill sedimentary succession in the central Japan Trench to reconstruct the long-term history of megathrust earthquakes and tsunamigenic slip-to-the-trench events. The expedition further sought to establish an integrated chronology of event deposits and deformation horizons, investigate earthquake-related fluid migration, and characterize carbon cycling, early diagenetic processes, and subseafloor microbial activity within the hadal trench-fill succession (Ikehara et al., 2025).

IODP³ Expedition 503 successfully recovered a continuous sedimentary succession from five holes. In total, 384.5 m of high-quality core was recovered, spanning the complete sedimentary succession of the hadal trench basin and extending into the underlying sedimentary sequence, and magnetostratigraphic constraints indicate that the recovered record extends back to at least the Middle Pleistocene (~773 ka).

The original Expedition 503 Science Team developed a broad, multidisciplinary analytical portfolio integrating a wide range of shipboard and post-expedition analytical approaches for chronological, sedimentological, stratigraphic, geochemical, paleomagnetic, structural geological, micropaleontological, microbiological, and petrophysical investigations.

With this work ongoing there are now opportunities to include new analytical directions that could complement the original research portfolio and further enhance the scientific value of Expedition 503 materials.

These include, but are not limited to:

• Additional chronological constraints,
• Expanded interstitial-water and sediment geochemistry
• Additional dissolved and gas-phase organic geochemical approaches
• Additional approaches to constrain low-temperature diagenesis and organic matter

Applications are welcomed from scientists scientists based in IODP³ Core and Associate Member nations, proposing to either: (a) adopt these or any other approaches to address the original objectives of the expedition without duplicating the plans of the original Science Team; or (b) use core samples recovered during the expedition to address new objectives and deliver new science not envisaged by the original expedition proposal

For more information please read the full call on the PDF below.

Applications must be submitted by 23:59 BST on Monday 21 September 2026 using the IODP³ Gateway system, accessed via Apply to Participate on the IODP³ webpage.