Marine Geophysics and Hydroacoustics

Tuaheni Landslides

SCHLIP3D - Submarine Clathrate Hydrate Landslide Imaging Project (Tuaheni Slides off the east coast of New Zealand)

The dynamics of submarine landslides is only poorly understood. While some landslides rapidly disintegrate others may stay as coherent blocks. Recently, it has been proposed that submarine landslides could also be characterized by very slow (creeping) deformation. The Tuaheni landslide complex off the east coast of New Zealand may acts as key site for investigating such slow-slipping landslides. We collected a 3D-seismic dataset covering parts of the slide complex by means of the so-called P-cable system during research cruise TAN1404 (13.04. – 08.05.2014) of the Kiwi Research Vessel RV Tanagaro. More... The P-cable system is a cost-efficient, low-fold, high resolution 3D-seismic acquisition system, which can be deployed on relatively small vessels. The used systems is operated by the GEOMAR Helmholtz Centre for Ocean Research Kiel. Main objectives of the survey include the development of a model for landslide evolution, the investigation of the methane hydrate system in the working area with special emphasis on its role for landslide dynamics, and the analysis of the deformations style for the Tuaheni landslide complex. Two competing hypotheses have been postulated to explain the deformation style: i) The Hydrate Valve suggest build-up of overpressure at the base of the gas hydrate stability zone beneath a shallow gas hydrate zone, which causes hydro-fracturing and induces small scale episodic mobility. ii) The Hydrate-Sediment Glacier postulates plastic behavior of gas hydrate bearing sediments resulting in continuous downslope creep. Gas hydrates are known to strengthen sediments during short-term deformation but it is unclear whether they may exhibit plastic behavior during slow deformation, similar to ice.

While the Hydrate Valve hypothesis is supported by theoretical models, recent laboratory experiments favor the hydrate-sediment glacier hypothesis. The 3D-seismic data will allow to map deformation indicators (compression, extension, shear zones, decollement) that will help distinguishing the kinematics of creep versus episodic slip. In addition, the data will significantly support planned drilling activities in the frame of IODP (Integrated Ocean Drilling Program) and with the robotic seafloor drilling rig MeBo during an upcoming RV Sonne cruise.

Contact person for the project: Sebastian Krastel

Partner institutes:

  • GEOMAR Helmholtz Centre for Ocean Research Kiel
  • GNS Science New Zealand
  • NiWa New Zealand

 

Cruises: R/V Tangaroa TAN1404 – 13.04.-08.05.2014

Project publications:

  • Gross, F., Mountjoy, J., Crutchley, G., Koch, S., Bialas, J., Pecher, I., Woelz, S., Dannowski, A., Carey, J., Micallef, A., Böttner, C., Huhn, K., Krastel, S. (2016) Submarine creeping landslide deformation controlled by the presence of gas hydrates: The Tuaheni Landslide Complex, New Zealand [Talk] In: EGU General Assembly 2016, 17.-22.04.2016, Vienna, Austria.
  • Gross, F., Krastel, S., Mountjoy, J., Crutchley, G., Pecher, I. (2015) The Tuaheni Landslide Complex – First results from the 3D seismic perspective [Poster] In: 7th International Symposium on Submarine Mass Movements and their Consequences, 01.11.-04.11.2015, Wellington, New Zealand.

 

Aussetzen des P-Cable Systems

Deployment of the P-cabel during cruise TAN1404.
 

 

Tuaheni Landslide, Bathymetry and 3D seismics

3D-seismic cube of the survey area off Gisborne, New Zealand. The data show slide deposits and active flares.