Researchers have discovered numerous tiny ice quakes occurring deep within Greenland’s ice streams. These quakes contribute to the movement of ice streams, which, contrary to previous assumptions of flowing like viscous honey, also exhibit a continuous stick-slip motion. The team recorded seismic activity using a fiber-optic cable installed in a 2,700-meter-deep borehole inside the ice stream.
The massive ice streams of Antarctica and Greenland function like frozen rivers, transporting ice from the vast inland ice sheets to the ocean. Changes in their movement play a crucial role in rising sea levels. To predict the extent of this rise, climate scientists rely on computer simulations of ice stream dynamics.
Traditionally, these simulations have assumed that ice streams move slowly and steadily, resembling the flow of thick honey. However, satellite observations reveal that this assumption is inaccurate.
The actual flow speeds of ice streams vary significantly, leading to flaws in existing models. As a result, current estimates of ice loss, the rate of ice discharge, and the projected rise in sea levels remain uncertain.
Ice streams both judder and flow
Now, a team of researchers led by ETH professor Andreas Fichtner has made an unexpected discovery: deep within the ice streams, there are countless weak quakes taking place that trigger one another and propagate over distances of hundreds of meters.
This discovery helps to explain the discrepancy between current simulations of ice streams and satellite measurements, and the new findings should also impact the way ice streams are simulated in the future.
“The assumption that ice streams only flow like viscous honey is no longer tenable. They also move with a constant stick-slip motion,” says Fichtner. The ETH professor is confident that this finding will be integrated into simulations of ice streams, making estimates of changes in sea level more accurate.
Riddles relating to ice cores resolved
Moreover, the ice quakes explain the origin of numerous fault planes between ice crystals in ice cores obtained from great depths. These fault planes are the result of tectonic shifts and have been known to scientists for decades, although no explanation had been found for them until now.
“The fact that we’ve now discovered these ice quakes is a key step towards gaining a better understanding of the deformation of ice streams on small scales,” explains Olaf Eisen, Professor at the Alfred Wegener Institute and one of the study’s co-authors.
The study by this international research team led by ETH Zurich has just been published in the journal Science and also involved researchers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), the University of Strasbourg, the Niels Bohr Institute (NBI), the Swiss Federal Institute WSL and other universities.
Fire and ice are related
The fact that these ice quakes cannot be observed at the surface and have therefore remained undiscovered until now is due to a layer of volcanic particles located 900 metres below the surface of the ice. This layer stops the quakes from propagating to the surface.
Analysis of the ice core showed that these volcanic particles originated from a massive eruption of Mount Mazama in what is now Oregon (USA) some 7,700 years ago. “We were astonished by this previously unknown relationship between the dynamics of an ice stream and volcanic eruptions,” Fichtner recalls.
The ETH professor also noticed that the ice quakes start from impurities in the ice. These impurities are also leftovers from volcanoes: tiny traces of sulfates that entered the atmosphere in volcanic eruptions and flew halfway around the world before being deposited on the Greenland ice sheet in snowfall. These sulfates reduce the stability of the ice and favor the formation of microfissures.
A 2,700-metre borehole in the ice
The researchers discovered the ice quakes using a fiber-optic cable that was inserted into a 2,700-metre-deep borehole and recorded seismic data from inside a massive ice stream for the first time. This borehole was drilled into the ice by researchers from the East Greenland Ice-core Project (EastGRIP), led by the Niels Bohr Institute and strongly supported by the Alfred Wegener Institute, resulting in the extraction of a 2,700-metre-long ice core. Once drilling work was complete, the researchers took the opportunity to lower a fiber-optic cable 1,500 meters into the borehole and record signals from inside the ice stream continuously for 14 hours.
The research station and borehole are located on the North East Greenland Ice Stream (NEGIS), around 400 kilometers from the coast. The NEGIS is the biggest ice stream of the Greenland ice sheet, whose retreat is a large contributor to current rising sea levels. In the area of the research station, the ice is moving toward the sea at a speed of around 50 meters per year.
As ice quakes occur frequently over a wide area in the researchers’ measurements, ETH researcher Fichtner believes it is also plausible that they occur in ice streams everywhere, all the time. To verify this, however, it will be necessary to take seismic measurements of this kind in other boreholes – and there are already plans to do just that.
Reference: “Hidden cascades of seismic ice stream deformation” by Andreas Fichtner, Coen Hofstede, Brian L. N. Kennett, Anders Svensson, Julien Westhoff, Fabian Walter, Jean-Paul Ampuero, Eliza Cook, Dimitri Zigone, Daniela Jansen and Olaf Eisen, 6 February 2025, Science.
DOI: 10.1126/science.adp8094
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10 Comments
I believe that mother nature has her own divine plan on taking care of this planet and when y’all go in there and make those holes to her gut through these areas where man should not be because they weren’t there before you to be able to stimulate it to do your bidding where you want it to go and how you wanted to act that’s on disrupting the entire world and another nature cuz now she’s not flowing right at all
“These quakes contribute to the movement of ice streams, which, contrary to previous assumptions of flowing like viscous honey, also exhibit a continuous stick-slip motion.”
Actually, glacial surging has been known for a long time: https://en.wikipedia.org/wiki/Surge_(glacier)
Also, embedded in glacial polish, one often finds arcuate cracks (~ 1 m in length) that are commonly called “chatter marks,” presumably similar to what happens when one drags their fingernails across a chalk board.
Lastly, glaciers are know to pluck blocks out of the down-stream side of the head wall and obstructions along its path. I would imagine that the release of a block would release a transient seismic signal similar to what they are recording.
Lastly, crevasses form in the upper 50-60 meters of ice under tension. Again, I wouldn’t be surprised that when crevasse initially form or extends that it will emit seismic energy.
These phenomena have been known for a long time. A better analogy to “viscous honey” would probably be the intermittent creep documented along the San Andreas and other faults.
I reason we will have a 2 foot rise in sea level by 2050. And massive population movments, 25 years. Better get your welly’s out!
Unfortunately the world left this one a bit late.
The world only fix things when lots of people die,
I’ll be 87 when 2050 comes around, by then they would have discoverd a cure for alzheimers.
Happy days!
Man cannot continue to exploit nature. The laws of nature will not allow it. She will fight back and she is empowered by the highest power. Do not be fooled by those who continuously deny the laws of God.
Or defy simple physics.
What has that got to do with the observations of natural processes?
I wouldn’t want to break the law! Can you provide me with a URL where I can read the “laws of nature” so that I don’t inadvertently break them? English text preferably. Most languages can be translated, but I doubt that the native language of Gaia or any of the various gods of the more than 4,300 extant religions are translatable. I wouldn’t want something to be corrupted or lost in the translation, so English only please, as provided by the God we should be paying attention to. Thanking you in advance —
Yes, history shows us that mankind will continue to exploit a resource, such as fossil fuels, even whales, until it effectively runs out!
Chatter marks in glacial polish. Presumably the glacial polish is on the rock beneath/beside the glacier. So one would need to consider the rheology of the glacial polish undergoing brittle failure even though the glacier in that area might be deforming by throughgoing simple shear (the ductile, “honey” model). What is interesting is the stick-slip model of deformation in a glacier where conditions, and hence assumptions, had us thinking of pervasive ductile deformation. Perhaps the rate of deformation is such that brittle failure has a role to play in such ductile deformation zones. Leads one to wonder about mineral deposits in rocks.
The point is, the authors are reporting sound coming from a geophone dropped down a bore hole and are assuming that the sounds are from the ice. What I was pointing out was that the sounds could just as easily be coming from the bedrock and the ice. They haven’t said how they could tell one from the other.