𝗠𝘆𝘀𝘁𝗲𝗿𝗶𝗼𝘂𝘀 𝗚𝗹𝗼𝗯𝗮𝗹 𝗦𝗲𝗶𝘀𝗺𝗶𝗰 𝗣𝘂𝗹𝘀𝗲 𝗧𝗿𝗮𝗰𝗲𝗱 𝘁𝗼 𝗠𝗲𝗴𝗮 𝗧𝘀𝘂𝗻𝗮𝗺𝗶 𝗶𝗻 𝗚𝗿𝗲𝗲𝗻𝗹𝗮𝗻𝗱

In September 2023, seismic stations worldwide picked up an unusual, rhythmic pulse repeating every 92 seconds a signal that persisted for nine straight days and mysteriously reappeared after a month. Too faint for humans to feel, but strong enough to register from Alaska to Australia, this baffling global signal left scientists searching for answers.
Their investigation led to Dickson Fjord in East Greenland a narrow, steep-sided inlet flanked by 3,000-foot cliffs. Satellite imagery later revealed a fresh scar where a massive chunk of mountain had collapsed into the water on September 16, 2023. The landslide, involving over 25 million cubic yards of rock and ice — equivalent to 10,000 Olympic swimming pools — triggered a colossal mega tsunami.
Waves as high as 650 feet surged down the fjord’s two-mile corridor, rebounding off the cliffs to create a powerful seiche — a trapped, oscillating water wave that sloshes repeatedly within an enclosed space. This phenomenon generated low-frequency seismic energy that rippled steadily through the Earth’s crust for days, explaining the unusual signal.
NASA and France’s Surface Water and Ocean Topography (SWOT) mission, launched in 2022, played a key role in solving the mystery. Satellite data captured subtle shifts in water elevation, matching predictions of seiche-induced oscillations. Machine learning simulations filled in the gaps, recreating the wave’s behaviour.
“It was exciting to be working on such a puzzling problem with an interdisciplinary and international team of scientists,” said Robert Anthony of the US Geological Survey.
This rare event underscores how dramatic geological processes in remote corners of the world can send ripples quite literally across the entire planet.