A Rockslide-Generated Tsunami in Greenland Fjord Rang Earth for 9 Days

On September 16th, 2023, a colossal rockslide occurred in Greenland, specifically in the remote Dickson Fjord. This event was not just a local catastrophe but also created ripples—both literal and figurative—that were felt around the globe. The rockslide generated a massive local tsunami, with waves towering up to 200 meters high, equivalent to twice the height of London’s Big Ben. This extraordinary event was a stark reminder of the power of natural forces and their ability to impact our planet on a global scale.

The rockslide-induced tsunami did not just stop at causing local devastation. It created a global seismic signal that lasted for an astonishing nine days. Researchers from around the world, intrigued by this unusual signal, began investigating its origins. The signal was so unique that it was initially classified as a ‘uso,’ or unidentified seismic object. Unlike typical seismic events caused by earthquakes, this signal had a continuous hum with only one vibration frequency, making it a scientific curiosity.

Svennevig et al., a team of researchers, employed various geophysical tools to study the events and determine the origin of this global signal. Their investigation revealed that the signal was caused by standing waves, known as seiches, in the Dickson Fjord. These seiches were the result of the massive displacement of water caused by the rockslide. The fjord’s unique geography trapped the energy from the tsunami, causing the water to oscillate back and forth for days, generating the persistent seismic signal detected worldwide.

The study by Svennevig et al. also highlighted the role of climate change in such events. The researchers pointed out that the thinning of glaciers due to global warming played a significant role in triggering the rockslide. As glaciers thin, they lose their ability to support the surrounding mountains, making landslides more likely. This particular rockslide involved a staggering 25 x 10^6 cubic meters of material, enough to fill approximately 10,000 Olympic-sized swimming pools. The collapse of this massive volume of rock and ice into the fjord was the catalyst for the subsequent tsunami and the prolonged seismic signal.

Climate change is not just affecting the cryosphere—the frozen parts of our planet—but also has cascading effects on the hydrosphere and lithosphere. The study showed that the interactions between these systems could lead to dangerous feedback loops. For instance, as glaciers melt and retreat, they can destabilize mountain slopes, leading to more frequent and larger landslides. These landslides, in turn, can generate tsunamis, which can have devastating local and global impacts. The Dickson Fjord event serves as a sobering example of these interconnected processes.

Interestingly, there have been no reported tsunamigenic landslides in the eastern fjords of Greenland before this event. This makes the September 2023 rockslide a particularly noteworthy case study. The seismic signal it generated was detected on sensors around the world, capturing the attention of scientists and researchers from various disciplines. A total of 68 experts from 15 countries collaborated to unravel the mystery of this unusual seismic event. Their collective efforts underscore the importance of international cooperation in understanding and mitigating the impacts of climate change.

The detailed simulations conducted by the researchers revealed that the initial 200-meter-high tsunami eventually stabilized into a 7-meter-high long-duration seiche. This seiche had a frequency of 11.45 millihertz, remarkably similar to the seismic signal’s frequency of 10.88 millihertz. The maximum amplitude of the oscillating force in the fjord was calculated to be 5 x 10^11 newtons. These findings highlight the importance of studying seiches to understand the complex interactions between the cryosphere, hydrosphere, and lithosphere.

The significance of this event extends beyond the immediate scientific community. It serves as a wake-up call about the far-reaching effects of climate change. As global temperatures continue to rise, we can expect to see more frequent and severe natural disasters, including landslides and tsunamis, particularly in polar regions. The Dickson Fjord rockslide is a harbinger of what may become a more common occurrence if current climate trends persist. Scientists warn that similar events are likely to happen in the future, emphasizing the urgent need for comprehensive climate action.

The collaborative nature of the research on this event is also worth noting. The joint Arctic command, the Sirius Dog Sled Patrol of the Kingdom of Denmark, and Northeast-Greenland Company Nanok provided invaluable cooperation and photos from the event. All initial and advanced scientific discussions were held virtually through the Mattermost platform, showcasing how modern technology can facilitate global scientific collaboration. Additionally, the Danish Agency for Data Supply and Infrastructure (SDFI) provided GNSS data crucial for the study.

The findings from this research have been made publicly available, along with the data and materials used, to allow for reproducibility. This transparency is essential for advancing our understanding of such complex natural phenomena. The eletters forum serves as a platform for peer review and constructive commentary on the article, fostering an environment of continuous learning and improvement. Figures and embedded figures are discouraged in eletters to maintain focus on the textual content and encourage detailed scientific discussions.

This event also highlights the importance of public awareness and education about the impacts of climate change. While the scientific community is well aware of the risks and consequences, it is crucial to communicate these findings to the general public effectively. Understanding the interconnectedness of natural systems and the potential for cascading effects can help in advocating for more robust climate policies and actions. The Dickson Fjord rockslide is a vivid example of how localized climate impacts can have global repercussions, affecting not just the environment but also human societies.

In conclusion, the rockslide-generated tsunami in Greenland’s Dickson Fjord and the subsequent nine-day-long global seismic signal serve as a powerful reminder of the intricate and far-reaching impacts of climate change. The event underscores the need for continued research and international cooperation to understand and mitigate these effects. As we move forward, it is imperative to take decisive action to address climate change and its myriad consequences. The Dickson Fjord event is not just a scientific curiosity but a clarion call for urgent and sustained efforts to protect our planet and future generations.