Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Studying real-time seismic activity

16.05.2003


A serendipitous discovery by a University of Colorado at Boulder-led team has shown for the first time that satellite signals from the Global Positioning System are a valuable new tool for studying seismic activity.



CU-Boulder Associate Professor Kristine Larson of aerospace engineering sciences said seismic waves from a 7.9 magnitude earthquake in Alaska’s Denali National Park in November 2002 were detected using Global Positioning Satellite, or GPS, receivers as far away as 2,350 miles from the event. The quake also was picked up by scores of GPS receivers in Canada and the United States.

GPS is a constellation of satellites originally designed by the U.S. military to provide precise positions of ships, tanks, airplanes, other military equipment and even people. Currently there are 27 GPS satellites orbiting Earth at roughly 12,500 miles above the planet.


"This is the first time GPS has been used to track seismic waves," Larson said. "The signals were large enough to be recorded by GPS receivers as far away as Colorado Springs, Colorado."

A paper on the subject will be published electronically by Science magazine on Science Express May 15. In addition to Larson, co-authors include Paul Bodin from the University of Memphis and Joan Gomberg from the U.S. Geological Survey’s Memphis office.

"The nice thing about GPS is it’s great versatility," said Larson. "In this study we were able to track seismic waves that traveled from Alaska through Canada to Washington, Montana and Colorado."

GPS also has a number of other scientific uses, like measuring ice sheet movements, the inflation of magma under volcanoes and plate tectonics, Larson said. More practical uses of GPS include navigating aircraft, boats and cars, as well as helping lost hikers find their way to safety.

GPS users -- like hikers, boaters and car drivers -- decide how frequently their position determination is needed. For measuring seismic waves from Denali, Larson’s team used GPS receivers that were set to measure positions once each second, or 1 Hertz.

Ordinarily, she said, scientists study earthquakes with seismometers, but these often are set for a particular sensitivity range. Because the earthquake in Alaska was so big, however, many seismometers in the United States and Canada were not able to measure it.

"But GPS researchers love very big signals," Larson said. "The bigger the better for us."

The Denali quake ruptured almost 200 miles, causing surface displacements of more than 25 feet in some places, she said. "This is permanent deformation. The deformations we observed with GPS in the lower 48 states also were large, but were caused by the seismic waves and did not cause permanent displacement."

For a sense of how big the seismic waves were, a GPS receiver in eastern Washington moved nine inches horizontally in just 10 seconds, even though it was 1,500 miles from the Denali earthquake.

There are many continuously operating GPS receivers in the United States, she said, and scientists use them primarily to monitor small motions on faults. Roughly 250 GPS receivers are operating in Los Angeles County, for example, installed in response to the 6.7 magnitude Northridge earthquake in 1994.

The National Science Foundation and Congress recently funded a research project known as Earthscope to study the structure and evolution of the North American continent, Larson said.

Earthscope also is designed to decipher what causes earthquakes and volcanic eruptions and as part of that effort, Earthscope engineers will soon be installing 800 additional GPS receivers in the western United States.


###
Contact:Kristine Larson, (303) 492-6583
Kristine.Larson@colorado.edu
Jim Scott, (303) 492-3114


Kristine Larson | EurekAlert!
Further information:
http://www.colorado.edu/

More articles from Earth Sciences:

nachricht Devils Hole: Ancient Traces of Climate History
24.05.2017 | Universität Innsbruck

nachricht Supercomputing helps researchers understand Earth's interior
23.05.2017 | University of Illinois College of Liberal Arts & Sciences

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>