Overview

• In September 2023 two glacier-thinning–induced landslides in East Greenland’s Dickson Fjord generated mega-tsunamis whose seismic signals recurred every 90 seconds for nine days.
• These mega-tsunamis formed trapped standing waves, or seiches, whose existence was previously inferred from seismic anomalies but lacked direct observation.
• The study published in Nature Communications applied SWOT’s Ka-band Radar Interferometer to produce high-resolution elevation maps showing water height oscillations of up to two meters.
• By correlating altimetry data with global seismic records and tidal models, researchers reconstructed seiche dynamics even during satellite observation gaps.
• Findings highlight the accelerating impact of climate-driven glacier thinning on Arctic geological extremes and demonstrate new capabilities for monitoring remote hazards.