Hidden cascades of seismic ice stream deformation

• 成果类型: Article
• 署名作者: Fichtner, Andreas; Hofstede, Coen; Kennett, Brian L. N.; Svensson, Anders; Westhoff, Julien; Walter, Fabian; Ampuero, Jean-Paul; Cook, Eliza; Zigone, Dimitri; Jansen, Daniela; Eisen, Olaf
• 署名单位: Swiss Federal Institutes of Technology Domain; ETH Zurich; Helmholtz Association; Alfred Wegener Institute, Helmholtz Centre for Polar & Marine Research; Australian National University; University of Copenhagen; Niels Bohr Institute; Swiss Federal Institutes of Technology Domain; Swiss Federal Institute for Forest, Snow & Landscape Research; Swiss Federal Institutes of Technology Domain; ETH Zurich; Centre National de la Recherche Scientifique (CNRS); Universite Cote d'Azur; Observatoire de la Cote d'Azur; Institut de Recherche pour le Developpement (IRD); Centre National de la Recherche Scientifique (CNRS); Universites de Strasbourg Etablissements Associes; Universite de Strasbourg; University of Bremen
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-13387
• DOI: 10.1126/science.adp8094
• 发表日期: 2025-02-21
• 页码: 858-864
• 关键词: last glacial period; greenland; sheet; core; EVOLUTION; holocene; records; egrip; tephrochronology; inclusions

摘要

Ice streams are major regulators of sea level change. However, standard viscous flow simulations of their evolution have limited predictive power owing to incomplete understanding of involved processes. On the Greenland ice sheet, borehole fiber-optic observations revealed a brittle deformation mode that is incompatible with viscous flow, over length scales similar to the resolution of modern ice sheet models: englacial ice quake cascades that are unobservable at the surface. Nucleating near volcanism-related impurities that promote grain boundary cracking, the ice quake cascades appear as a macroscopic form of crystal-scale wild plasticity. A conservative estimate indicates that seismic cascades are likely to produce strain rates that are comparable in amplitude with those measured geodetically, providing a plausible missing link between current ice sheet models and observations.