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

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>