Scientists have uncovered the source of a mysterious, long-lasting seismic signal detected globally. This signal, a very-long-period (VLP) wave at 10.88 mHz, followed two massive tsunamigenic landslides in Greenland's Dickson Fjord in September and October…
Earth’s Mysterious 90-Second Pulse: Dickson Fjord Solved!
In September 2023, scientists detected a strange phenomenon: the Earth pulsed every 90 seconds for nine days straight. This wasn’t an earthquake or an explosion; the signals, detected globally, seemed to originate from the remote Dickson Fjord in East Greenland. Scientists were baffled. What caused this rhythmic pulsing? Now, thanks to a new study, we have the answer.
Two Groundbreaking Studies
To investigate, two independent studies surfaced with differing explanations for this unusual seismic event. They both proposed that this signal was caused by a seiche phenomenon, which can occur when water shifts dramatically within enclosed spaces like fjords. While one study estimated an initial amplitude of approximately 2.6 meters, another claimed it reached 8.8 meters. This substantial difference highlights the challenges scientists face in remote areas where data and observations are limited.
The Role of Satellite Technology
Furthermore, the breakthrough came from the use of cutting-edge satellite technology. Specifically, data from NASA and CNES’s Surface Water and Ocean Topography (SWOT) satellite provided unprecedented detail. Unlike previous technology, SWOT’s wide scan area allowed researchers to observe the previously elusive phenomenon. Researchers used the data to map water surface elevation changes in the fjord, revealing clear evidence of a standing wave, a seiche, oscillating back and forth.
How SWOT works
The SWOT satellite utilizes cutting-edge technology to measure sea-surface heights with precision, providing data that was previously difficult to obtain over vast areas, especially in challenging environments like Dickson fjords. With resolutions down to 2.5 meters, these measurements enable scientists to observe and understand extreme events, including tsunamis and seismic waves.
A Glacier-Driven Avalanche
Moreover, the study revealed that two massive glacier-driven rock-ice avalanches triggered the unusual seismic activity. These avalanches launched tsunami waves, approximately 7.9 meters high. However, the confined geography of the fjord trapped the wave’s energy, causing the rhythmic seiche that lasted for days and generated the globally detected signals. This is a truly remarkable discovery!
Climate Change and the Arctic
In addition, this event highlights the impact of climate change on the Arctic. Rising temperatures are destabilizing glaciers, increasing the likelihood of such catastrophic landslides. The researchers emphasize that the Arctic is experiencing rapid change, and this study underscores the need for advanced monitoring tools to better understand these extreme events.
Reference
- Monahan, T., Tang, T., Roberts, S., & Adcock, T. a. A. (2025). Observations of the seiche that shook the world. Nature. https://doi.org/10.1038/s41467-025-59851-7
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Neha Adikane holds a Master’s degree in Environmental Science from Pune University, bringing a unique blend of scientific expertise and creative writing skills to her craft. She specializes in creating engaging, insightful, and impactful content across various niches. With a passion for translating complex ideas into simple, relatable narratives, she excels at crafting blogs, articles, website content, and social media posts that captivate readers and drive engagement. Neha’s background in environmental science adds depth to her writing, allowing her to effectively cover topics related to sustainability, eco-awareness, and scientific innovations.