Countless Ice Quakes Were Recorded For The First Time Deep Inside Greenland’s Biggest Frozen River
Deep inside Greenland’s biggest frozen river, the Northeast Greenland Ice Stream, countless ice quakes were recorded for the first time.
These quakes may explain why the frozen rivers move downstream toward the ocean in such an erratic way instead of in a slow, steady flow.
Researchers detected the quakes by lowering a fiber-optic cable into a borehole 1.7 miles deep in the Northeast Greenland Ice Stream, which serves as the main route for ice from the interior of the Greenland Ice Sheet to pass through to the North Atlantic Ocean.
Ice quakes are similar to earthquakes. They occur when ice fractures and two slabs grind against each other. Until now, ice quakes in Greenland have gone undetected because a layer of volcanic particles located 2,950 feet below the ice prevented them from reaching the surface.
The particles originated from a large eruption of Mount Mazama about 7,700 years ago in what is now the state of Oregon.
Volcanic particles are responsible for preventing seismic waves from reaching the surface, but they may also be the direct cause of the quakes themselves.
It is likely that the ice quakes start from impurities in the ice, which destabilizes it and leads to the formation of small cracks. Ice quakes can trigger other ice quakes, so they can spread over long distances.
“We were astonished by this previously unknown relationship between the dynamics of an ice stream and volcanic eruptions,” said Andreas Fichtner, the lead author of the study and a professor of geophysics at the Swiss Federal Institute of Technology in Zurich.
The research team was interested in uncovering how ice streams behave because they are major contributors to rising sea levels—and the ice quakes may also be playing a role in this process.
Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox.
Ice streams dump massive amounts of ice from glaciers into the sea, and their rate of flow is correlated to how quickly sea levels rise.
Previously, scientists thought that ice streams moved slowly like thick honey. However, the new findings show that they have a more complex pattern of movement.
“The assumption that ice streams only flow like viscous honey is no longer tenable,” said Fichtner. “They also move with a constant stick-slip motion.”
The discovery of the relationship between ice stream dynamics and volcanic eruptions provides valuable insights, but there is still much to learn about how they affect sea levels and what it means for climate change.
The Greenland Ice Sheet is the largest ice sheet in the Northern Hemisphere. It covers about 80 percent of Greenland’s landmass.
Since the 1990s, meltwater from the ice sheet has accounted for a 0.6-inch increase in sea levels. Greenland has enough ice to raise sea levels by an estimated 23 feet.
The study was published in the journal Science.
More About:News
Read This Next
