Giant Tsunami from Melting Glacier... Tremors Spread Worldwide
Collapsed Glacier Holds Volume Equivalent to 10,000 Swimming Pools
Last September, a landslide caused by the melting of the Dixon Fjord glacier in Greenland was found to have shaken the entire Earth for nine days. This was due to a massive 198-meter-high tsunami generated by the landslide.
This is the first confirmation that water vibrations can be transmitted to the Earth's crust, and that these vibrations can propagate worldwide for several days.
On the 14th (local time), CNN and others reported this, citing research results published in the scientific journal Science by an international research team led by Dr. Kristian Svennevi of the Geological Survey of Denmark and Greenland (GEUS).
The research team received reports from Danish authorities that a large tsunami had occurred in the fjord near the Nanok and Ella Ø research stations in northeastern Greenland after an unknown-origin seismic signal with a very long period (VLP) was detected in eastern Greenland last September.
This seismic signal, with a frequency of 10.88 millihertz (mHz, 92-second period), was nicknamed the "Unidentified Seismic Object" (USO).
Glacier in Greenland. The photo is not directly related to the article content. [Image source=Pixabay]
Subsequently, research was conducted to identify the nature of the seismic event using seismometer and ultrasound data, field measurements, ground and satellite images, and tsunami wave simulations. The research group included 68 scientists from 40 institutions across 15 countries, including Denmark, the United Kingdom, France, Germany, and the United States.
Simulation results indicated that as the glacier beneath the mountain melted, a 1,200-meter-high mountain peak collapsed into Dixon Fjord, causing a water column to surge up to 200 meters and generating a tsunami with a maximum height of 110 meters.
The rocks and ice that collapsed into the fjord due to this landslide were estimated to total 25 million cubic meters, enough to fill 10,000 Olympic-sized swimming pools.
Model experiments showed that the water crossing the 10-kilometer fjord could not escape and continued to move back and forth for nine days. The research team estimated that the tsunami’s height would have decreased from 7 meters within minutes to a few centimeters after several days.
They added, “This is the first observation of a landslide and tsunami of this scale in eastern Greenland,” explaining that “the landslide occurred because the glacier at the mountain’s base had thinned, making it unable to support the rock above.”
Dr. Svennevi emphasized, “As the pace of climate change accelerates, monitoring and providing information on large-scale landslides and tsunamis in areas previously considered stable will become increasingly important.”
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