In September 2023, seismic stations around the world began recording a puzzling rhythmic pulse—repeating every 90 seconds and lasting for an astonishing nine days, even briefly returning a month later. Unlike typical earthquakes or volcanic tremors, this signal was faint yet detectable from Alaska to Australia. The enigma captured global attention: what mysterious event could trigger such persistent, low-frequency vibrations?
Scientists ultimately traced the phenomenon to **Dickson Fjord in East Greenland**, where a colossal landslide plunged into the fjord, triggering a massive **650‑foot mega‑tsunami**. This wave sloshed back and forth—creating a **seiche**, or standing wave—for over a week, generating seismic reverberations around the globe. The discovery highlighted the revolutionary role of satellite technology, machine learning, and climate data in unveiling unseen natural disasters caused by a warming Arctic.
---
### 1. Seismic Sensors Sound the Alarm
In September 2023, something extraordinary happened: seismic stations worldwide registered an unsettling rhythmic tremor—a booming globe‑spanning “hum” every **90 seconds**. This noise wasn’t seismic in the usual sense. No plates were shifting. No earthquakes erupted. It was a steady, persistent signal—something unprecedented. Scientists initially labeled it **unidentified seismic object.
As Dr. Stephen Hicks from University College London later explained, “It kept appearing—every 90 seconds for nine days.” This mystery sparked intense online discussions and collaboration among geophysicists, seismologists, and climate scientists—as they pieced together a vast, multidisciplinary puzzle.
---
### 2. Uncovering the Source: Greenland’s Hidden Fury
Investigators soon connected the rhythmic tremor with a **massive landslide** in Dickson Fjord, Eastern Greenland. In mid‑September 2023, a chunk of glacier‑buttressed mountainside around 1.2 km high gave way. Over **25 million cubic meters** of rock and ice—equivalent to **10,000 Olympic swimming pools**—tumbled into the fjord with tremendous force.
That impact generated a **mega‑tsunami**, estimated to be about **200 meters (650 feet)** tall. The cliff that collapsed initially produced even larger waves—possibly reaching **360 feet**—before stabilizing at around **200 meters**([ndtv.com][4]). Imagine the equivalent of half a football field standing tall—that was the wave crashing into the fjord.
---
### 3. What Is a Seiche—and Why Did It Last So Long?
Unlike typical tsunamis, which dissipate rapidly in the open ocean, this wave was **trapped** in the narrow fjord, flanked by walls nearly 1,800 meters tall and plunging 540 meters deep([ndtv.com][4]). The confined waters caused the mega‑tsunami to reflect off fjord walls—creating a **seiche**, a permanent sloshing motion.
This back‑and‑forth rocking happened every **90 seconds**, matching the seismic signal. With limited escape, the tremor reverberated for an incredible **nine days**, the sloshing slowly diminishing but still registering globally.
Seiches are common in lakes or pools, but on this scale—maintaining a massive slosh for days—it was unprecedented. Dr. Hicks said, “We’ve never seen such a large‑scale movement of water over such a long period.”
---
### 4. Piecing Together the Puzzle
Solving this seismic mystery required global collaboration—**68 scientists from 40 institutions** across the U.S., Europe, Africa, and Asia worked together for over a year They combined:
* **Seismic data**: To determine the source’s location and frequency of the harmonic tremor.
* **Drone and military vessel images**: Provided by the Danish navy days later, showing fresh landslide debris and waterline scars.
* **Satellite radar data (SWOT/KaRIn)**: Used to map the wave’s amplitude across the fjord.
* **Advanced modeling**: High‑resolution computer simulations that recreated how the wave sloshed and decayed over time.
* **Bathymetric maps**: From the Danish navy, to understand the fjord’s underwater geography.
The breakthrough came by fusing these diverse data streams. Survey maps and satellite imagery allowed precise modeling of the wave’s travel and oscillation pattern. Simulations matched the **11.45 mHz** seiche frequency measured on seismic arrays.
---
### 5. Climate Change: The Underlying Trigger
This mega‑tsunami wasn’t a freak natural fluke—it was **climate‑driven**.
Rising Arctic temperatures are **thinning glaciers**, destabilizing the slopes they support. In Greenland, the ice retreat beneath Hvide Støvhorn peak led to the collapse([thehindu.com][2]). Dr. Kristian Svennevig of GEUS stated plainly: “Climate change set the stage for the landslide by melting the glacier at the base of the mountain, destabilizing more than 25 million cubic meters of rock and ice".
Arctic warming—up to **four times faster** than the global average—is increasing landslide and tsunami risks in fjords, permafrost areas, and coastal glaciers([euronews.com][6]). Similar events (2017 Greenland, Alaska's Barry Arm) raise alarms for Arctic stability and hazard management.
---
### 6. Technology: The Detective Tools
Unraveling this event required cutting‑edge tools:
* **SWOT satellite (2022)**: Equipped with Ka-band Radar Interferometer (KaRIn), capable of high-precision water-surface mapping. It captured the mega-tsunami’s shape during a close.
* **Machine learning**: Used in conjunction with seismic and satellite data to estimate wave amplitude (≈ 7.9 m) and isolate the unique signal from background noise.
* **High-resolution modeling**: Extensive simulations replicated wave behavior in the fjord—accounting for geography, depth, and slosh duration.
Dr. Virginia noted: “SWOT happened to fly over at a time when the water had piled up pretty high… seeing the shape of the wave—something we could never do before”
---
### 7. Global Implications and Risks Ahead
Though no people died, the mega-tsunami caused substantial damage to infrastructure—around **US\$200,000**—at a deserted research station on Ella Island Cultural heritage sites were also affected.
This event highlights:
* **Hidden dangers**: Remote fjords can harbor tsunami risks even in the absence of earthquakes.
* **Climate exacerbation**: As Arctic warming continues, such cascading natural disasters may increase in frequency and scale.
* **Surveillance needs**: Calls for early-warning systems, advanced satellite monitoring, and Arctic risk modeling are growing.
* **Policy urgency**: Risk assessments for shipping routes and Arctic infrastructure must now account for climate-triggered landslides.
Dr. Hicks reflected:
> “This event is perhaps the first time a climate-change event has impacted the crust beneath our feet all over the world."
> He warns: “Now we’ve seen it, we have to deal with it.”
---
### 8. Lessons Learned & Scientific Breakthrough
The Dickson Fjord mega-tsunami reshapes our understanding of natural hazards:
* **Extended-duration seismic signals**: Harmonic tremors need to be evaluated for hydrodynamic sources, not just tectonics or volcanism.
* **Interdisciplinary teamwork**: Combining seismology, satellite data, modeling, and on-site investigations can solve high-complexity events.
* **AI in geoscience**: Machine learning is revolutionizing how we reconstruct and interpret planetary-scale phenomena.
According to Prof. Adcock:
> “This study shows how we can leverage the next generation of satellite Earth‐observation technologies to study these processes".
---
### 9. Future Outlook: A Planet on Shaky Ground
Climate models now predict increased frequency of glacier-supported landslides and mega-tsunamis in retreating-fjord regions. Arctic warming is destabilizing terrain at scale:
* **Barry Arm Glacier (Alaska)**: Active monitoring after similar warning signs.
* **Cultural heritage sites** https://www.profitableratecpm.com/h5sevimm?key=39681fc5da315145da57cc03388182ad : Popular cruise destinations need detailed hazard maps to prevent loss.
Experts underscore the need for rapid deployment of:
1. **Automated remote sensing platforms**—for near-real-time detection of slope instability.
2. **AI-enhanced seismic monitoring**—to catch long-period signals early.
3. **Global coastal assessments**—lifesaver planning linked to deep-water tsunami modeling.
---
### 10. A Climate Wake-up Call
The 650-foot mega-tsunami is more than geological drama—it’s a climate-era alert bell. Arctic glacier retreat can destabilize landscapes and unleash natural disasters that send shockwaves—literally—across the globe.
As we continue warming, silent hazards lurk in remote corners. Without vigilant monitoring, dramatic events like Dickson Fjord’s mega-tsunami could happen again—potentially with human and ecological loss.
---
## Conclusion
Greenland’s mega-tsunami was a wake-up call—a dramatic, nine-day global shudder sparked by a hillside collapse in a glacier-thin fjord. It illustrated the profound interplay between **climate change** and **earth systems**, and showcased how innovative technologies—satellites, machine learning, global science cooperation—are essential in deciphering our changing planet.
As Dr. Hicks poignantly observed,
> “Had you suggested just a year ago that a nine-day wave could exist on a Greenland seafloor … people would shake their heads. Now we’ve seen it, we have to deal with it.”
This atmospheric event rings a planetary warning: the Earth is speaking in rumbling seiches and mega-tsunamis. It's time we listened.
---
Comments
Post a Comment