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 Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>