Overview

• Two glacier-triggered landslides in East Greenland during September and October 2023 unleashed megatsunamis that produced standing waves oscillating every 90 seconds for nine days.
• NASA’s Surface Water Ocean Topography satellite and its Ka-band Radar Interferometer captured up to two-meter sea surface height variations across Dickson Fjord, providing the first direct observations of the seiches.
• Global seismic stations recorded ultra-low-frequency tremors at 10.88 millihertz that precisely matched the fjord’s oscillations, enabling researchers to reconstruct wave dynamics.
• The initial seiche reached an estimated height of 7.9 meters and exerted forces of roughly 500 giganewtons—equivalent to 14 Saturn V rockets launching simultaneously.
• The findings highlight how climate-driven glacier thinning destabilizes remote fjord landscapes and demonstrate the value of next-generation satellites for monitoring emerging ocean extremes.