Testing the veracity of turbidite paleoseismology using the Kaikōura earthquake-triggered turbidite, New Zealand

To better understand earthquake reoccurrence and hazard, records of ancient earthquakes spanning millennia are routinely generated using seabed turbidite deposits, inferred to be synchronously triggered by strong ground motions over large geographic areas. However, the use of turbidites for paleoseismology is underpinned by untested hypotheses due to the dearth of verified earthquake-triggered turbidite deposits produced by well-characterised earthquakes. The aim of a RV Tangaroa voyage in October 2019 was to use the unique opportunity provided by the widespread and documented occurrences of the 2016 Mw7.8 Kaikōura earthquake-triggered turbidite to determine whether synchronous turbidite deposition can be reconstructed from the sedimentary record alone. Our presentation will summarise insights gleaned from precision short cores and high-resolution sub-bottom profiles collected along and across the axis of submarine canyons that preserve turbidite deposits triggered by the Kaikōura earthquake. Planned detailed laboratory characterisation of the turbidites will include high-resolution core imaging, texture, densitometry, down-core physical properties and geochemical characterisation combined with radioisotope-derived chronology. Through repeat coring at historical sites and future coring campaigns we hope to also quantify the impact of biological mixing on the Kaikōura event deposit to determine its likely preservation potential in the geological record. Our results have the potential to provide the first robust test of turbidite paleoseismology.