A rockslide-generated tsunami in a Greenland fjord rang the Earth for 9 days

Journal article

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 a 9-day-long global 10.88 mHz (92 s) monochromatic very long-period (VLP) seismic signal, originating from East Greenland. We demonstrate how this event started with a 25×106 m3 glacial thinning-induced rock-ice avalanche 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 (11.45 mHz) 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.

Authors: Svennevig, K; Hicks, SP; Forbriger, T; Lecocq, T; Widmer-Schnidrig, R

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Association for the Advancement of Science
• Journal: Science
• Volume: 385
• Issue: 6714
• Pages: 1196–1205
• Publication date: 2024-09-12
• Acceptance date: 2024-08-06
• DOI: 10.1126/science.adm9247
• EISSN: 1095-9203
• ISSN: 0036-8075
• Language: English
• Keywords: FFR