Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High-resolution images herald new era in Earth sciences

10.04.2007
High-resolution images that reveal unexpected details of the Earth's internal structure are among the results reported by MIT and Purdue scientists in the March 30 issue of Science.

The researchers adapted technology developed for near-surface exploration of reservoirs of oil and gas to image the core-mantle boundary some 2,900 kilometers, or 1,800 miles, beneath Central and North America.

"Rather than depth, it's the resolution and lateral scale that are unique in this work," said lead author Rob van der Hilst, professor of earth, atmospheric and planetary sciences (EAPS) and director of MIT's Earth Resources Laboratory. "This could lead to a new era in seismology and all the other deep Earth sciences. In addition, our new expertise may be able to improve how we look for oil in or beneath geologically complex structures such as the Gulf of Mexico salt domes," he said.

The technique--akin to medical imaging such as ultrasounds and CAT scans--led to detailed new images of the boundary between the Earth's core and mantle. These images, in turn, help researchers better understand how and where the Earth's internal heat is produced and how it is transported to the surface. They also provide insight into the Earth's giant heat engine--a constant cycle of heat production, heat transfer and cooling.

The Earth is made up of the outermost rocky crust, which is around 40 kilometers deep; iron and magnesium silicates of the upper and lower mantles; and the liquid outer core and solid inner core.

Scientists have long assumed that the lower mantle is relatively featureless. But more detailed views have indicated that there is more complexity than expected. "I expect that the Earth is full of such surprises, and with these new imaging technologies and data sets, we have only just begun to scratch the surface of possibilities afforded by modern data sets," van der Hilst said.

Reflecting waves

Deeply propagating waves generated by large earthquakes hit the core-mantle boundary and bounce back--as if from a mirror--to the Earth's surface.

Each time one of these waves hits an underground structure, it emits a weak signal. "With enough data, we can detect and interpret this signal," van der Hilst said. Using data from thousands of earthquakes recorded at more than 1,000 seismic observatories, an interdisciplinary team of earth scientists and mineral physicists led by van der Hilst pinpointed the details of deep earth structures. The cross-disciplinary study involved seismologists, mathematicians, statisticians and mineral physicists from the University of Illinois and Colorado School of Mines in addition to MIT and Purdue.

The imaging technique was introduced 20 years ago as a powerful tool for finding subsurface reservoirs of gas or oil. Meanwhile, over the past decades, large arrays of seismometers have been installed at many places in the world for research on earthquakes and the Earth's interior. "It is now possible to begin applying techniques developed by the oil industry to these large earthquake databases," van der Hilst said.

The idea for the research reported in Science was born over breakfast in a Cambridge, Mass., Au Bon Pain some five years ago, when Maarten de Hoop, an applied mathematician at Purdue University, and van der Hilst realized that they might be able to pair up the industry tools and the earthquake data to study the core-mantle boundary in ways never before possible.

Years of work by Ping Wang, EAPS graduate student at MIT, led to the possibility for high-resolution imaging, and in collaboration with EAPS mineral physicist Dan Shim, the team produced maps of temperature and heat flow some 3,000 kilometers below the Earth's surface, using the data to provide a kind of "seismothermometer" of the Earth's temperature at extreme depths.

No one has ever seen the turbulently swirling liquid iron of the outer core meeting the silicate rock of the mantle--10 times as far below ground as the International Space Station is above--but the cross-disciplinary study led the researchers to estimate the temperature there is a white-hot 3,700 degrees Celsius.

Because of rich data available for the region between Central and North America, the researchers used this area as their first application of the tools, mapping millions of square kilometers underground. They hope to apply the techniques around the globe and perhaps to image an even more remote boundary of the inner core close to the center of the Earth.

This work was supported by the National Science Foundation.

Elizabeth Thomson | EurekAlert!
Further information:
http://www.mit.edu

More articles from Earth Sciences:

nachricht Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

nachricht Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>