ChatGPT: Three people wearing University of Innsbruck T-shirts stand in front of a large drilling tower on a research vessel. — Co-Chief Scientist Michael Strasser (Department of Geology) with Charlotte Pizer (Department of Geology) and Paloma Gea (Department of Microbiology) on board the research vessel Chikyu (from left). Mishelle Mutre (Department of Geology) will join the team when the ship docks in Shimizu.

Innsbruck Scientists Conduct Deep-Sea Research in the Japan Trench

03.12.2025

As part of the international deep-sea research initiative IODP3, a team from the University of Innsbruck’s Departments of Geology and Microbiology is currently participating in a three-week expedition to the Japan Trench. Aboard Japan’s drilling vessel Chikyu, the scientists analyze sediments from deep below the seafloor in a trench at water depth exceeding 7600 meters to investigate traces of past megathrust earthquakes and microbial activity in the hadal zone.

Four scientists from the University of Innsbruck are currently taking part inIODP3 Expedition 503 “Hadal Trench Tsunamigenic Slip History – Buried in Trench BIT,” which has been underway since 24 November on Japan’s deep-sea drilling vessel Chikyu and continues until 12 December. In total, around 25 scientists from several countries are working on board. Michael Strasser, head of the Department of Geology at the University of Innsbruck, serves as Co-Chief Scientist alongside Ken Ikehara of the Geological Survey of Japan (AIST). The mission focuses on a part of the Japan Trench where the seafloor reaches more than 7600 meters at the drilling site. Sediments are being recovered from up to 160 meters below the seafloor to study the geological imprint of past megathrust earthquakes and the activity of microorganisms in this extreme environment.

The International Ocean Drilling Program (IODP3) is the world’s leading framework for scientific ocean drilling. The current expedition is enabled by JAMSTEC, Japan’s Agency for Marine-Earth Science and Technology, which operates the Chikyu. The strong participation of Innsbruck-based scientists highlights Austria’s visibility in this major international research program.

Chikyu bow view — The bow of the D/V Chikyu with its Japanese name visible, seen from the dock. — Bow view of the D/V *Chikyu* from the dock.

The Chikyu’s drilling system lowering the drill pipe through the moonpool into the ocean. — The drill bit penetrates the seafloor to recover sediment cores.

Insights into Earthquake Cycles and Microbial Activity

On board, Innsbruck is represented by geologists Charlotte Pizer and Mishelle Muthre, who specialise in stratigraphy, palaeoseismology and sedimentary processes, and by microbiologist Paloma Gea from the Rinke Lab, who investigates microbial life in the hadal zone. Also on board from the University of Innsbruck is Melanie Bartos, who accompanies the entire expedition as its science communicator and reports on the work of the international research teams.
The sediment cores are being analyzed directly on board in geological, geochemical and microbiological laboratories. These studies aim to clarify how often major earthquakes occur in this part of the Japan Trench, how the deep-sea benthic environments evolve under extreme conditions, and how microorganisms contribute to biogeochemical processes in the deepest parts of our world´s ocean. These processes are also crucial for understanding the global carbon cycle and, hence, climate dynamics. With their combined expertise, the Innsbruck scientists make a significant contribution to this IODP3 expedition.