要点
- The megatsunami in Dickson Fjord in September 2023 shook the Earth every 90 seconds for 9 days
- Two megatsunamis 200 meters high formed due to avalanches resulting from glacier thinning
- Narrow fjord geometry trapped water, sustaining the "seiche" oscillation for days
- 2025 Nature Communications study explained the event with fjord resonance
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In September 2023, seismometers around the world recorded a recurring low-frequency vibration every 90 seconds for nine days. This regular signal originated not from an earthquake, volcanic eruption, or nuclear test, but from a megatsunami occurring in Dickson Fjord on Greenland's east coast.
Two major ice and rock avalanches (September 16 and October 11, 2023) created a 200-meter megatsunami in the narrow and deep fjord. Because the water could not escape to the open ocean, an oscillation known as a "seiche" began between the fjord walls, and this oscillation struck the fjord flanks every 90 seconds, generating global seismic waves.
A study published in Nature Communications in 2025 explained how the fjord's unique geometry transformed this local event into a global phenomenon. The thinning of glaciers is weakening rocks, indicating that similar events may increase with climate change.
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よくある質問
- What happened in Greenland and how was the Earth affected?
- The megatsunami in Dickson Fjord caused the water to oscillate back and forth in the narrow fjord, creating a global seismic vibration every 90 seconds for 9 days.
- What caused the megatsunami?
- Glacier thinning weakened the rocks on the sides, and two major ice-rock avalanches (September 16 and October 11, 2023) created 200-meter megatsunamis.
- Can such an event happen again?
- Yes, if climate change continues to melt glaciers, similar avalanches and fjord resonance events may increase.