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

2024; American Association for the Advancement of Science; Volume: 385; Issue: 6714 Linguagem: Inglês

10.1126/science.adm9247

1095-9203

Kristian Svennevig, Stephen Hicks, Thomas Forbriger, Thomas Lecocq, Rudolf Widmer‐Schnidrig, A. Mangeney, Clément Hibert, Niels J. Korsgaard, Antoine Łucas, Claudio Satriano, R. E. Anthony, Aurélien Mordret, Sven Schippkus, Søren Rysgaard, Wieter Boone, Steven J. Gibbons, Kristen Cook, Sylfest Glimsdal, Finn Løvholt, Koen Van Noten, Jelle Assink, Alexis Marbœuf, Anthony Lomax, Kris Vanneste, T. Taira, Matteo Spagnolo, Raphaël De Plaen, Paula Koelemeijer, Carl Ebeling, Andrea Cannata, William D. Harcourt, David G. Cornwell, Corentin Caudron, Piero Poli, Pascal Bernard, Éric Larose, É. Stutzmann, Peter Voß, Björn Lund, Flavio Cannavò, Manuel J. Castro, Esteban J. Chaves, Trine Dahl‐Jensen, Nicolas De Pinho Dias, Aline Déprez, Roeland Develter, Douglas S. Dreger, Läslo Evers, Enrique D. Fernández-Nieto, Ana M. G. Ferreira, G. J. Funning, Alice‐Agnes Gabriel, Marc Hendrickx, A. L. Kafka, Marie Keiding, Jeffrey T. Kerby, Shfaqat Abbas Khan, Andreas Kjær Dideriksen, Oliver D. Lamb, Tine B. Larsen, Bradley P. Lipovsky, Ikha Magdalena, Jean‐Philippe Malet, Mikkel Myrup, Luis Rivera, Eugenio Ruiz‐Castillo, Selina Wetter, Bastien Wirtz,

earthquake and tectonic studies

Climate change is increasingly predisposing polar regions to large landslides. Tsunamigenic landslides have occurred recently in Greenland ( Kalaallit Nunaat ), but none have been reported from the eastern fjords. In September 2023, we detected the start of a 9-day-long, global 10.88-millihertz (92-second) monochromatic very-long-period (VLP) seismic signal, originating from East Greenland. In this study, we demonstrate how this event started with a glacial thinning–induced rock-ice avalanche of 25 × 10 6 cubic meters plunging into Dickson Fjord, triggering a 200-meter-high tsunami. Simulations show that the tsunami stabilized into a 7-meter-high long-duration seiche with a frequency (11.45 millihertz) and slow amplitude decay that were nearly identical to the seismic signal. An oscillating, fjord-transverse single force with a maximum amplitude of 5 × 10 11 newtons reproduced 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.