Featured Research

from universities, journals, and other organizations

Earth's Core-Mantle Boundary: Now In High Resolution Images

Date:
April 7, 2007
Source:
Massachusetts Institute of Technology
Summary:
High-resolution images can now be used to reveal unexpected details of the Earth's internal structure. 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.

Seismic waves from earthquakes penetrate the Earth's mantle and scatter back at the core-mantle boundary to detectors on the surface. Nearly 100,000 such recordings are used to illuminate the planet's deep internal structures.
Credit: Image courtesy / Robert van der Hilst, MIT

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.

Related Articles


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.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. Note: Materials may be edited for content and length.


Cite This Page:

Massachusetts Institute of Technology. "Earth's Core-Mantle Boundary: Now In High Resolution Images." ScienceDaily. ScienceDaily, 7 April 2007. <www.sciencedaily.com/releases/2007/04/070406171041.htm>.
Massachusetts Institute of Technology. (2007, April 7). Earth's Core-Mantle Boundary: Now In High Resolution Images. ScienceDaily. Retrieved December 17, 2014 from www.sciencedaily.com/releases/2007/04/070406171041.htm
Massachusetts Institute of Technology. "Earth's Core-Mantle Boundary: Now In High Resolution Images." ScienceDaily. www.sciencedaily.com/releases/2007/04/070406171041.htm (accessed December 17, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Wednesday, December 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ivory Trade Boom Swamps Law Efforts

Ivory Trade Boom Swamps Law Efforts

Reuters - Business Video Online (Dec. 17, 2014) Demand for ivory has claimed the lives of tens of thousands of African elephants and now a conservation report says the illegal trade is overwhelming efforts to enforce the law. Amy Pollock reports. Video provided by Reuters
Powered by NewsLook.com
Uphill Battle to Tackle Indonesian Shark Fishing

Uphill Battle to Tackle Indonesian Shark Fishing

AFP (Dec. 17, 2014) Sharks are hauled ashore every day at a busy market on the central Indonesian island of Lombok, the hub of a booming trade that provides a livelihood for local fishermen but is increasingly alarming environmentalists. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
France's Sauternes Wine Threatened by New Train Line

France's Sauternes Wine Threatened by New Train Line

AFP (Dec. 16, 2014) Winemakers in southwestern France's Bordeaux are concerned about a proposed high speed train line that could affect the microclimate required for the region's sweet wine. Duration: 01:06 Video provided by AFP
Powered by NewsLook.com
2016 Olympic Waters Feature 'Super Bacteria' Researchers Say

2016 Olympic Waters Feature 'Super Bacteria' Researchers Say

Newsy (Dec. 16, 2014) Researchers found the bacteria Klebsiella pneumoniae Carbapenemase in the water where the 2016 Olympics is supposed to take place. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins