Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U. of Colorado researchers pioneer new technique for imaging Earth’s interior

11.03.2005


Seismologists have long relied on earthquakes or expensive tools like explosives to help create images of Earth’s interior, but a new method created by University of Colorado at Boulder researchers will produce quicker, cheaper and clearer images.



Rather than waiting for earthquakes, the researchers have now recovered surface wave information from ambient seismic noise that is constantly produced by fluctuations in the Earth’s atmosphere and oceans. Measuring surface waves is important because they help scientists get a clearer picture of the Earth’s interior, according to Michael Ritzwoller, director of CU-Boulder’s Center for Imaging the Earth’s Interior and a physics professor.

"This new technique will give us a better fundamental understanding of the planet by providing much better resolution of Earth’s interior," Ritzwoller said. "It also will diminish what is known in seismology as the ’tyranny of earthquakes,’ which means having to wait for an earthquake to happen to do our jobs."


The new method promises significant improvements in the resolution and accuracy of crustal and upper mantle images down to 60 miles or more within the Earth, particularly when used in tandem with seismic projects like USArray, according to Nikolai Shapiro, a research associate in the Center for Imaging the Earth’s Interior and the study’s chief author.

A paper on the technique appears in the March 11 issue of the journal Science. Co-authors include Ritzwoller of CU-Boulder and Michel Campillo and Laurent Stehly of the Laboratory of Geophysics and Tectonophysics at the Joseph Fourier University in Grenoble, France.

In a process similar to a medical CT scan, researchers have for some years been constructing tomographic images of Earth’s crust and upper mantle from waves generated by earthquakes. This method, known as seismic tomography, reconstructs Earth’s inner structure on a computer screen, slice by slice. The new CU-Boulder method is similar, but is based on organizing ambient seismic noise, which is typically discarded as seismic garbage.

While the new method offers no help in predicting when earthquakes will happen, it can provide information for risk assessment. And it will be a very useful tool for USArray researchers, Ritzwoller said.

"The risk that the public faces is not only from the earthquake, but how waves emanated from the earthquake interact with the inner-structure of the Earth," Ritzwoller said. This new measuring technique, coupled with existing and emerging technology such as USArray, will lead to a better fundamental understanding of the structure of the planet and may help save lives in the process, he said.

A component of the National Science Foundation’s program EarthScope, USArray is a massive seismic project using hundreds of portable seismometers that in coming years will be moved across the entire country, producing images of the Earth’s interior. The project’s goal is producing new data about the Earth’s interior, including earthquake risk assessment. The CU-Boulder findings should be extremely useful to USArray researchers, according to Ritzwoller.

Seismic tomography is like doing a medical CT scan of the Earth, Ritzwoller said. During a CT scan, the body goes into the machine, which takes multiple X-rays and then uses a computer to construct cross-sectional views of the body or body parts. Seismologists have previously relied on waves generated from earthquakes to reconstruct images of the inner Earth.

However, when people have a CT scan, doctors are in control and can make images at will. Seismologists can’t control when an earthquake happens, so they can either wait, or they can set off explosives to create their own waves to generate images of the Earth’s interior.

But each of these methods has drawbacks. "To move beyond these limitations requires observational methods based on seismic sources other than earthquakes, which is what our method offers," said Shapiro.

Michael Ritzwoller | EurekAlert!
Further information:
http://www.colorado.edu

More articles from Earth Sciences:

nachricht How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena

nachricht Canadian glaciers now major contributor to sea level change, UCI study shows
15.02.2017 | University of California - Irvine

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>