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Scientists have discovered the cause of giant underwater landslides in Antarctica that they believe may have triggered tsunamis that rippled across the Southern Ocean.
An international team of researchers has discovered layers of weak, fossilized, biologically rich sediments hundreds of meters below the sea floor.
These landslides formed under vast areas of underwater landslides, many of which cut more than 100 meters into the sea floor.
Writing Nature CommunicationsScientists say that these weak layers — composed of historical biological material — made the region vulnerable to failures in the face of earthquakes and other seismic activity.
They also highlighted that the layers formed at a time when temperatures in Antarctica were 3 degrees Celsius higher than they are today, when sea levels were higher and ice sheets were much smaller than they are now.
With the planet currently going through a period of widespread climate change – including warming waters again, rising sea levels and shrinking ice sheets – researchers believe there is potential for such incidents to recur.
By analyzing the effects of previous underwater landslides, they say that future seismic events off the coast of Antarctica may again pose a risk of tsunamis reaching the shores of South America, New Zealand and Southeast Asia.
Landslides in the eastern Ross Sea were discovered in 2017 by an international team of scientists during the Italian ODYSSEA expedition.
Scientists revisited the area in 2018 as part of the International Ocean Discovery Program (IODP) Expedition 374 as they collected samples from sediment samples that extend hundreds of meters below the sea floor.
By analyzing these samples, they found microfossils that painted a picture of what the climate in the region might have been like millions of years ago and how it created the vulnerable layers in the depths of the Ross Sea.
The new study was led by Dr Jenny Gallis, Lecturer in Hydrography and Ocean Exploration at the University of Plymouth, and part of IODP Expedition 374.
She said, “Undersea landslides are a major geographic hazard that can trigger tsunamis that can lead to huge loss of life. Landslides can also destroy infrastructure including undersea cables, which means that such future events It will create a wide range of economic and social impacts.Thanks to the exceptional preservation of sediments beneath the sea floor, we have been able for the first time to show the cause of these historic landslides in this region of Antarctica, as well as indicate the impact of such events in the future.Our findings highlight on how we urgently need to enhance our understanding of how global climate change is affecting the stability of these regions and the potential for future tsunamis.”
Professor Rob Mackay, Director of the Antarctic Research Center at Victoria University of Wellington and co-lead scientist for IODP Expedition 374 added: “The main objective of the IODP drilling project in 2018 was to understand the impact that a warming climate and oceans are having on the melting of the Antarctic ice sheets. However, when Dr. Gallis and her colleagues aboard the OGS Explora spacecraft charted these massive dips and landslides the year before, it was quite a revelation for us to see how the past changes in climates that we were studying from drilling operations were related. directly related to undersea landslide events of this magnitude. We did not expect to see this, and it is a potential hazard that definitely warrants further investigation.”
Laura De Santis, a researcher at the National Institute of Oceanography and Applied Geophysics in Italy who is also the co-lead scientist for IODP Expedition 374, said: “The sediment samples we analyzed were obtained as part of IODP, the international scientific seafloor drilling project that has remained active in The field of Earth sciences for more than 50 years. The project aims to explore the history of planet Earth, including ocean currents, climate change, marine life, and mineral deposits, by studying sediments and rocks under the sea floor.”
Jan Sverre Laberge, from the Arctic University of Norway, Tromsø, said: “Giant undersea landslides have occurred on both the southern and northern continental margins, including the Antarctic and Norwegian continental margins. More knowledge about these events will be in Antarctica Also relevant for the geographical assessment of submarines off the coast of Norway.
Dr Amelia Chevenel, Assistant Professor of Geo-oceanography at the University of South Florida, College of Marine Sciences, said: “This study demonstrates the importance of scientific ocean drilling and marine geology for both understanding past climate change and identifying areas of natural hazards to report on. Infrastructure decisions – potentially that large landslides along the Antarctic Rim trigger tsunamis, which can lead to significant loss of life far from their origin.Furthermore, National Antarctic Programs are examining the possibility of installing submarine cables to improve communications from research bases in Antarctica.Our study is located , from the slope of the Ross Sea, towards the sea for the main national and international research stations, indicating that geological and marine geophysical feasibility studies are essential to the success of these projects and must be completed early in the development process, before countries invest in and rely on this communications infrastructure.
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