Earthquake Archive in the GEological Record of the Japan Trench (EAGER-Japan)

Austrian Science Fund (FWF) - (2016-2020)
Project number P29678-N28

PI Michael Strasser 
Project members: Arata Kioka (Postdoc) and Tobias Schwestermann (PhD Student)


Inspecting the sediment (Credit: Sebastian Trütner)Our perspective of earthquake maximum magnitude and recurrence is limited by short historical and even shorter instrumental records, which are inadequate to fully characterize Earth’s complex and multi-scale seismic behavior. Motivated by the mission to fill the gap in knowledge about the long-term history of great earthquakes, we investigate the traces, which major earthquakes leave behind on the ocean floor to calibrate the marine sediment record for studying past earthquake in geological archives. As documented after the devastating Magnitude 9 Japan Earthquake and Tsunami in 2011, continuous records of comparable past natural impacts are preserved in the geological archive as characteristic event deposits formed by soft marine sediments remobilized by turbidity currents, that were induced due to instabilities of the ocean floor upon strong earthquake shaking.

Research expedition onboard R/V Sonne (Credit: Paul Töchterle)The EAGER-Japan projects aims at characterizing and precise dating of such extreme event deposits from the marine geological record of the Japan Trench by applying novel analytical techniques applied on samples recovered from the deep sea during sea-going research expeditions. In particular, we aim at identifying the source and transport dynamics of materials remobilized during past extreme events by analyzing composition and texture of individual sand grains, and to measure radioactive decay of individual organic compounds to constrain the timing when such remobilization occurred in the past. The results of these analyses will reveal a dense spatio-temporal data set elucidating when and where strong earthquake shaking has impacted the ocean floor offshore NE Japan in the past. While contributing to unravel a potentially fascinating earthquake history for Japan beyond any current knowledge from historical archive, anticipated conceptual advances in our understanding of causes and consequences of earthquakes and related geological processes in offshore environments are expected to be transformative to other regions worldwide, and may even open up new perspectives for deciphering the rock-record from outcrops on land.  

 

Project collaborators
Jasper Moernaut (University of Innsbruck) 
Achim Kopf  (MARUM, University of Bremen) 
Toshiya Kanamatsu (Japan Agency for Marine-Earth Science and Technology - JAMSTEC)
Shuichi Kodaria (Japan Agency for Marine-Earth Science and Technology - JAMSTEC)
 
Ken Ikehara (Geological Survey of Japan)
Tim Eglinton (ETH Zürich)
Cecilia McHugh (Queens College, New York)

Master-students associated to the EAGER Japan Project:
Jana Molenaar and Dominik Jeager