Tiny Quakes Discovered Deep Within Greenland’s Ice Sheet Could Change Sea-Level Rise Predictions, Study Suggests

Greenland’s ice sheet is melting at an alarming rate, contributing to rising sea levels worldwide. But a new discovery could change the way scientists predict the future of ice streams and clarify their role in this process.

For the first time, researchers have identified tiny quakes occurring deep within Greenland’s fast-flowing ice streams. This seismic shaking results in a “stick-slip” motion—in other words, the ice’s movement is irregular, with brief accelerations broken up by pauses. The discovery challenges long-standing assumptions about how ice flows, and it might have significant implications for predicting sea-level rise.

In a new study published in Science this month, an international team of researchers lowered a fiber-optic cable almost one mile down into a borehole in the Northeast Greenland Ice Stream (NEGIS), the largest ice stream in the Greenland ice sheet. The cable measured seismic activity deep within the ice, and what it revealed shocked the team. Rather than the steady, slow flow scientists expected, the ice quivered with tiny seismic disturbances.

When he first saw the data, lead author Andreas Fichtner, a seismologist at ETH Zürich in Switzerland, recalls thinking it was “rubbish” and “just some electronic noise,” as he tells Raymond Zhong of the New York Times. However, as the team dug deeper, they realized they had uncovered something fundamental about how ice streams behave.

When one of these weak quakes occurs, it sets off another, and a chain reaction of tiny tremors propagates over large areas. These so-called “ice quakes” are thought to be triggered by impurities in the ice, which originated from volcanic activity thousands of years ago. These impurities make the ice weaker and more prone to cracking, creating the quakes.

The discovery offers a new way to understand the dynamics of ice streams, which are crucial contributors to rising sea levels. Ice streams like NEGIS carry massive amounts of ice from the interior of the Greenland ice sheet to the ocean, and their rate of flow is directly tied to how quickly sea levels rise. Until now, scientists assumed these ice streams moved in uniform, slow fashion, like thick syrup. However, the new findings suggest a more complex movement pattern.

“The assumption that ice streams only flow like viscous honey is no longer tenable,” Fichtner says in a statement. “They also move with a constant stick-slip motion.”

Swiss-led research reveals hidden ice quakes in Greenland@ETH-led research finds tiny ice quakes deep in Greenland’s ice streams, revealing a stick-slip motion instead of steady flow​.

2,700m borehole & fibre optics recorded the quakes
Improves sea-level rise… pic.twitter.com/jxhCLt5f0A

— About Switzerland (@AbtSwitzerland) February 10, 2025

This new understanding could help improve the accuracy of simulations used to predict how much ice will melt—and, in turn, how quickly sea levels will rise. Current models, which are based on the assumption that ice streams flow steadily, have shown discrepancies when compared to satellite measurements.

Olaf Eisen, a co-author of the study from the Alfred Wegener Institute, notes that this discovery also helps explain why ice cores, taken from deep within the ice sheet, contain fractures called fault planes between ice crystals, per the statement. These fault planes, previously unexplained, are now understood to be the result of the tiny quakes occurring deep in the ice.

“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,” Eisen says in the statement.

The research also highlights an unexpected connection between volcanic activity and ice stream behavior. After analyzing the volcanic particles in the ice, the team traced them to a 7,700-year-old eruption of Mount Mazama, which is located in Oregon today. Those volcanic sulfates traveled around the world through the atmosphere and eventually fell with snow onto Greenland, reducing the stability of the ice and making it more susceptible to the tiny quakes.

“We were astonished by this previously unknown relationship between the dynamics of an ice stream and volcanic eruptions,” Fichtner says in the statement.

While this discovery provides valuable insights, researchers caution that there is still much to learn. Andy Aschwanden, a glaciologist at the University of Alaska Fairbanks who was not involved in the research, tells the New York Times that while the findings are important, it’s too early to say how much it will change scientists’ ability to predict sea levels.

Regardless, “all of us who study ice,” as Richard B. Alley, a geoscientist at Penn State University who is not an author of the study, tells the New York Times, “will be building on this new paper for a long time to come.”

Ella Jeffries | READ MORE

Ella Jeffries is an editorial intern with Smithsonian magazine.