Underwater canyon study informs landslide risk evaluation

Underwater canyon study informs landslide risk evaluation
by Robert Schreiber
Berlin, Germany (SPX) Feb 24, 2025

The German research vessel SONNE is set to launch an expedition near New Zealand. Led by Kiel University, teams from CAU and the GEOMAR Helmholtz Centre for Ocean Research Kiel will explore underwater canyons on active and passive continental slopes in the southwest Pacific until 22 March.

Funded by the BMBF, the MAWACAAP project seeks to identify factors influencing landslide frequency, magnitude and distribution in collaboration with GNS and NIWA. The findings will improve global risk assessments to protect coastal communities and subsea assets, with Expedition SO310 leaving Wellington for extensive seismic and geological surveys.

Comparing dynamic and stable continental margins

The Palliser and Pegasus Canyon sites, situated merely 190 kilometres apart along New Zealand's coast, occupy contrasting geological settings. Palliser lies along an active plate boundary prone to earthquake-triggered landslides, whereas Pegasus Canyon, on a quieter margin, features extensive sediment buildup. Fluctuating sea levels linked to climate change may further destabilize these deposits. Despite earlier research, direct field comparisons remain scarce, a gap this expedition aims to address.

Chief Scientist Professor Dr. Sebastian Krastel, Head of the Marine Geophysics and Hydroacoustics Working Group at Kiel University, states, "We hope that the new data we will obtain from the extensive seismic measurements and the sediment cores collected during the cruise will help us to better understand the hazard and risk potential of large underwater canyons for the coasts," adding that "On this new expedition, we have the unique opportunity to directly compare different underwater canyons."

In Depth Seismic Survey and Core Drilling Plan

The expedition will undertake broad seismic surveys and sediment sampling to investigate geological and climatic factors affecting sedimentary structures. Researchers will assess the strength and permeability of deposits and produce bathymetric maps to gauge the dimensions and chronology of previous landslides.

Their objective is to compile a database linking landslide frequency to volume, offering key indicators for risk assessment. Co-chief scientist Dr Anke Dannowski from the GEOMAR Helmholtz Centre for Ocean Research Kiel observes, "If we understand the influence of rock strata, the role of topography and the frequency and size of submarine landslides, we can also better predict future canyon activity,"

On 17 February, a reception was held aboard the vessel in Wellington Harbour by the German Embassy and the Federal Ministry of Education and Research (BMBF) for 50 invitees. During the climate talks, researchers from Germany and New Zealand shared their work under the theme "German and New Zealand Research - The Power of Synergies"