Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Scientists detect seasonal pattern to glacial earthquakes in Greenland, see signs of increase


Rise of seismic activity linked to the movement of glaciers may be a response to global warming

Seismologists at Columbia University and Harvard University have found a new indicator that the Earth is warming: "glacial earthquakes" caused when the rivers of ice lurch unexpectedly and produce temblors as strong as magnitude 5.1 on the moment-magnitude scale, which is similar to the Richter scale. Glacial earthquakes in Greenland, the researchers found, are most common in July and August, and have more than doubled in number since 2002.

Seismologists Göran Ekström and Victor C. Tsai at Harvard and Meredith Nettles at the Lamont-Doherty Earth Observatory, a member of The Earth Institute at Columbia University, will publish a report on Greenland’s glacial earthquakes this week in the journal Science. Ekström, Nettles and colleagues first described glacial earthquakes in 2003, but that report did not recognize the seasonality or increasing frequency of the phenomenon.

"People often think of glaciers as inert and slow-moving, but in fact they can also move rather quickly," says Ekström, professor of geology and geophysics at Harvard who will be moving to Lamont-Doherty in the spring. "Some of Greenland’s glaciers, as large as Manhattan and as tall as the Empire State Building, can move 10 meters in less than a minute, a jolt that is sufficient to generate moderate seismic waves."

As glaciers and the snow atop them gradually melt, water seeps downward. When enough water accumulates at a glacier’s base, it can serve as a lubricant, causing blocks of ice 10 cubic kilometers in size to lurch down valleys known as "outlet glaciers," which funnel all of Greenland’s glacial runoff toward the surrounding seas.

"Our results suggest that these major outlet glaciers can respond to changes in climate conditions much more quickly than we had thought," says Nettles, a postdoctoral researcher at Lamont-Doherty. "Greenland’s glaciers deliver large quantities of fresh water to the oceans, so the implications for climate change are serious. We believe that further warming of the climate is likely to accelerate the behavior we’ve documented."

Although Greenland is not known as a hotbed of traditional seismic activity caused by the grinding of the Earth’s tectonic plates, seismometers worldwide detected 182 earthquakes there between January 1993 and October 2005. Ekström, Nettles and Tsai examined the 136 best-documented of these seismic events, ranging in magnitude from 4.6 to 5.1. All were found to have originated at major valleys draining the Greenland Ice Sheet, implicating glacial activity in the seismic disturbances.

Moreover, of the earthquakes they analyzed, the researchers found more than one-third occurred during the months of July (22 earthquakes) and August (24). By comparison, January and February each saw a total of only such four glacial earthquakes between 1993 and 2005. In contrast, non-glacial earthquakes in northern latitudes show no such seasonal variability.

In addition, the number of glacial earthquakes in Greenland increased markedly between 1993 and 2005. Annual totals hovered between 6 and 15 through 2002, which was followed by sharp increases to 20 earthquakes in 2003, 24 in 2004 and 32 in the first ten months of 2005. A single area of northwestern Greenland, where only one seismic event was observed between 1993 and 1999, experienced more than two dozen glacial quakes between 2000 and 2005.

Although glacial earthquakes appear to be most common in Greenland, Ekström, Nettles and Tsai have also found evidence of glacial earthquakes originating from mountain glaciers in Alaska and at glaciers located in ice streams among the edges of Antarctica.

Ken Kostel | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union

nachricht UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>