Abstract: Climate change is increasingly predisposing polar regions to large landslides. Tsunamigenic landslides have occurred recently in Greenland, but none have been reported from the eastern fjords. In September 2023, we detected the start of an unprecedented up to 9-day-long global 10.88mHz (92s) monochromatic very-long period (VLP) seismic signal, originating from East Greenland. We demonstrate how this event started with a 25 M m3 glacial thinning-induced rockslide plunging into Dickson Fjord, triggering a 200 m high tsunami. Simulations show the tsunami stabilized into a 7 m-high long-duration seiche with a near-identical frequency (11.45mHz) and slow amplitude decay as the seismic signal. An oscillating, fjord-transverse single-force with a maximum amplitude of 5×1011 N reproduces the seismic amplitudes and their radiation pattern relative to the fjord, demonstrating how a seiche directly caused the 9-day long seismic signal. Our findings highlight how climate change is causing cascading, hazardous feedbacks between the cryosphere, hydrosphere and lithosphere.
These results are published in Science (doi:10.1126/science.adm9247).
This repository contains codes used in our analysis and information required to prepare the figures in the manuscript and supplementary material.
The repository follows the structure of the manuscript, where codes and/or instructions and data sources are provided for each figure and its subplots:
fig1\: Seismic signal, position, and local setting
fig2\: Landslide observations.
fig3\: Landslide seismic signal and modelling.
fig4\: Tsunami observations and modeling
fig5\: VLP seismic signal and comparison with simulated seiche
supplementary\: Figures in the supplementary materials.
bathymetry\: Detailed bathymetry of the Kempe Fjord area.
seiche\: input parameters and output time series for the HySEA tsunami simulation that shows a fjord seiche
CTD data are available from an associated repository: https://www.vliz.be/nl/imis?dasid=8425&doiid=921.