When a remote mountainside collapsed into a narrow Greenland fjord, it did more than send water racing toward the coast. The impact generated a towering wall of water roughly 650 feet high that ricocheted between rock walls and made the planet vibrate for nine days. Only later did a global web of satellites and seismometers reveal that this hidden mega-tsunami had turned a quiet Arctic inlet into a planetary-scale bell.
The event, centered in Greenland’s Dickson Fjord, began as a landslide but evolved into a trapped wave that refused to die out. I see it as a preview of a climate era in which warming-driven instability in polar landscapes can trigger hazards that are both intensely local and globally detectable.
The landslide that primed a Greenland fjord
The story starts with rock, ice, and gravity. In northeastern Greenland, a steep slope above Dickson Fjord had been weakened by a combination of glacial retreat and thawing permafrost, a pattern that researchers have linked to accelerating glacial activity and permafrost thaw. On September 16, 2023, that slope finally failed, sending a massive volume of rock plunging into the fjord and instantly displacing an enormous mass of seawater. The geometry of Dickson Fjord, long and steep-sided, meant that the energy had nowhere to spread out, so it surged upward instead.
Field surveys and numerical models later showed that the initial wave crest reached a staggering 650-Foot height near the impact zone, a scale that justifies calling it a Foot Mega Tsunami rather than an ordinary landslide wave. Scientists tied the trigger directly to Climate Change, arguing that a Triggered Landslide Unleashes enough energy to turn a single unstable slope into a global signal. In that sense, the collapse was not an isolated accident but part of a broader reshaping of Greenland’s coasts as ice retreats and frozen ground loses its grip.
A 650-foot wave that would not die
What made this event extraordinary was not only the height of the water wall but its persistence. Instead of racing outward across the open ocean, the wave became trapped inside the fjord, sloshing back and forth in what physicists call a seiche. Satellite analysis later confirmed that the initial crest reached about 650-foot height, then rebounded between the steep walls of Greenland’s Dickson Fjord like water in a giant bathtub. Each oscillation lost a little energy to turbulence and friction, but the basin was so efficient at trapping motion that the seiche persisted for more than a week.
From orbit, a constellation of instruments watched the water surface heave and fall. An international mission that included SWOT and Sentinel-2 tracked the unique contours of the trapped wave, with one analysis describing how an international satellite mission detected the oscillation as it sloshed within the steep walls. Later work showed that the same 650-foot mega-tsunami was captured in high resolution as it set the fjord in motion, with 650-foot wave heights recorded by satellites and seismic waves propagating worldwide for nine days. In effect, the fjord became a resonant cavity, slowly bleeding its energy into the crust of the planet.
The mystery tremor that rang around the world
Long before anyone had pieced together what happened in Dickson Fjord, seismologists were staring at a puzzle. Instruments scattered across Earth for monitoring earthquakes and nuclear tests began to pick up a low, rhythmic vibration that did not match any known quake sequence. The signal repeated with clockwork regularity, yet there was no obvious epicenter. For days, the tremor made the Mystery of its origin a topic of intense debate among Scientists, with researcher Jeff Kerby and colleagues eventually tracing the pattern back to a massive landslide in a remote Greenland fjord that generated vibrations for nine days.
At first, some experts suspected a slow earthquake or even anthropogenic activity, but the frequency content and global reach did not fit. Later reporting described how the Mega tsunami mystery was only solved once satellite footage revealed the frightening cause of the earth-shaking vibrations that had affected the world for 9 days. A detailed reconstruction later showed that the oscillating water column in Dickson Fjord was injecting rhythmic energy into the surrounding bedrock, turning a local wave into a global hum that sensitive instruments could pick up on every continent.
How satellites finally cracked the case
The breakthrough came when researchers began to cross match seismic records with high resolution imagery and radar data from multiple space missions. In the days surrounding the unexplained tremors, satellites had captured subtle but unmistakable changes in the water surface of a remote Greenland inlet. Analysts noticed that a long, narrow fjord was pulsing in sync with the global signal, its surface rising and falling in a pattern that matched the seismometers. A detailed reconstruction of the event later showed how a remote Greenland fjord had unleashed a colossal force that silently shook the entire planet, leaving Scientists baffled until they realized the vibrations came from a different kind of origin than a typical earthquake.
Multiple analyses converged on the same conclusion. One synthesis described how Mega Tsunamis That Shook the World for 9 Days Revealed in New Satellite Images were finally tied to the trapped wave in Dickson Fjord, with Scientists using overlapping radar, optical, and altimetry data to map the oscillation. Another account framed the event as a Greenland mega tsunami that made the planet ring for days, with A Greenland mega tsunami finally proved why the signal had such a distinctive, long lasting character. Together, these lines of evidence turned a baffling seismic anomaly into a well documented chain of cause and effect.
A climate era warning and what comes next
For me, the most unsettling part of this story is not the spectacle of a 650-foot wave but the conditions that made it possible. Researchers have been clear that the landslide in Dickson Fjord was shaped by a warming Arctic, where retreating ice and thawing ground destabilize slopes that have been frozen in place for centuries. One synthesis framed the event as a climate era warning signal, noting that On September 16 a single slope failure in Greenland turned into a global vibration that lasted more than a week. Another analysis of why Mega tsunamis keep happening in Greenland emphasized how, for days, each oscillation pushed against the fjorded walls and surrounding bedrock, days each oscillation injecting rhythmic energy into the Earth and underscoring how sensitive the system has become to sudden mass movements.
The scientific payoff has been significant. The research, published in Nature Communications, confirms what modelers had long suspected but never directly observed, that a tsunami can become a trapped wave that sloshes within a basin and continues oscillating for over a week. Video explainers on Mega tsunamis in a Greenland fjord have since walked viewers through how the source of the nine day signal was confirmed, with one breakdown noting that it is not the first place you would think to look and that right it’s not the first place you would expect such a global effect. Another explainer invites viewers to imagine being a seismologist anywhere on Earth in September 2023, suddenly seeing a strange pattern on your screen and then learning that Nov Earth wide tremors were being driven by a single Greenland fjord. For hazard planners, the lesson is blunt. As Tsunamis and related seiches become easier to monitor with space based tools, agencies like NASA and others argue that satellite technology and monitoring tsunamis can help build safer and more resilient communities, especially in polar regions where the next Greenland scale shock may already be taking shape.
In retrospect, the Greenland event reads like a case study in how modern observation networks can turn a baffling planetary riddle into a coherent narrative. Early coverage described how a landslide triggered a mega-tsunami and then something inexplicable, with one account calling the seismic signal completely unprecedented in the global record. Later syntheses of Mysterious Mysterious mega-tsunamis that shook the entire world for 9 days, framed as News By Ben Turner, underlined how the source of these seiches was found only when satellites and seismometers were analyzed together. One summary put it plainly, Dec Earth wide data showed that a 650-foot mega-tsunami is recorded by seismic waves and satellites, sending seismic waves worldwide for nine days. Another noted that Jan Greenland coverage made clear that satellites capture 650-Foot Mega Tsunami hitting Greenland, with seismic shockwaves shaking the globe for nine full days. For a planet entering a new climate regime, that kind of forensic clarity may be as important as any seawall.
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