Featured Research

from universities, journals, and other organizations

Evidence Found For Molten Rock Two Thousand Miles Beneath Earth's Surface

Date:
February 12, 1998
Source:
National Science Foundation
Summary:
Deep inside the earth, two thousand miles beneath its surface, pockets of molten rock can be found in a region where many scientists did not expect to find anything but solid rock. Researchers funded by the National Science Foundation report the finding in this week's issue of the journal Nature.

Deep inside the earth, two thousand miles beneath its surface, pockets of molten rock can be found in a region where many scientists did not expect to find anything but solid rock. Researchers funded by the National Science Foundation report the finding in this week's issue of the journal Nature.

Related Articles


"One of the most exciting puzzles in the earth is the nature of mantle convection, which is the driving force of earthquakes," says Jim Whitcomb, NSF program director for geophysics. "This study is an important step in characterizing the lower boundary of that convection in a newly discovered region above the core-mantle boundary."

Based on their analysis of seismic waves measured in Norway, scientists John Vidale of Univeristy of California, Los Angeles and Michael Hedline of University of California, San Diego have produced the most convincing data yet for the existence of molten rock deep within the earth's mantle.

"Just as temperature varies tremendously at different parts of the earth's surface, there also seem to be large temperature differences 2,000 miles beneath the earth, above the core-mantle boundary," says Vidale, who studies the region between the earth's mantle -- a thick layer of rock -- and its outer core. "For example, areas with many volcanoes and earthquakes, like the western United States, have hotter rock underneath than regions with 'less exciting' geology, like the midwest or southeastern U.S. We may be seeing signs of a similar variety of activities deep within the earth."

Vidale and Hedlin analyzed seismic waves from 25 earthquakes of magnitude 6.0 or higher that have struck the southwest Pacific island of Tonga -- the locale with more major earthquakes than anywhere on earth. The measurements were generated by a network of 132 seismometers spread over 60 miles in Norway, instruments that were originally deployed in the 1960s to monitor the Soviet Union's nuclear weapons testing. Seismic vibrations from Tonga radiate through the earth, and reach seismometers in Norway in about 20 minutes.

The scientists' analysis reveals that seismic waves hit an obstacle that causes the waves to change direction, or scatter. By studying this scattering, they were able to draw conclusions about the boundary between earth's core and mantle. "The best and perhaps only explanation for the large amount of scattering in the seismic waves is that part of the rock in the mantle is melted," explains Vidale.

The new study detected a slurry of molten rock across a 300-by-600-mile region deep beneath Tonga.

Closer to home, volcanic plumes that erupt in Hawaii and thermal phenomena like the geysers in Yellowstone may originate in the core-mantle boundary, but that remains to be proven, says Vidale. A goal of his research is to learn whether material is transported from the core to the mantle, and vice versa.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. "Evidence Found For Molten Rock Two Thousand Miles Beneath Earth's Surface." ScienceDaily. ScienceDaily, 12 February 1998. <www.sciencedaily.com/releases/1998/02/980212072550.htm>.
National Science Foundation. (1998, February 12). Evidence Found For Molten Rock Two Thousand Miles Beneath Earth's Surface. ScienceDaily. Retrieved April 18, 2015 from www.sciencedaily.com/releases/1998/02/980212072550.htm
National Science Foundation. "Evidence Found For Molten Rock Two Thousand Miles Beneath Earth's Surface." ScienceDaily. www.sciencedaily.com/releases/1998/02/980212072550.htm (accessed April 18, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Saturday, April 18, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nervous Return to Everest a Year After Deadly Avalanche

Nervous Return to Everest a Year After Deadly Avalanche

AFP (Apr. 18, 2015) In the Himalayan town of Lukla, excitement mingles with fear as mountaineers make their way up to Everest a year after an avalanche killed 16 guides and triggered an unprecedented shut-down of the world&apos;s highest peak. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
L.A. Water Cops Remind Residents of Water Conservation

L.A. Water Cops Remind Residents of Water Conservation

Reuters - US Online Video (Apr. 18, 2015) "Water cops" in Los Angeles remind the public about water conservation methods amid California&apos;s prolonged drought. Julie Noce reports. Video provided by Reuters
Powered by NewsLook.com
Planet Defence Conference Tackles Asteroid Threat

Planet Defence Conference Tackles Asteroid Threat

AFP (Apr. 17, 2015) Scientists gathered at a European Space Agency (ESA) facility outside Rome this week for the Planetary Defence Conference 2015 to discuss how to tackle the potential threat from asteroids hitting Earth. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
Gulf Scarred, Resilient 5 Years After BP Spill

Gulf Scarred, Resilient 5 Years After BP Spill

AP (Apr. 17, 2015) Five years after the Deepwater Horizon spill in the Gulf of Mexico, splotches of oil still dot the seafloor and wads of tarry petroleum-smelling material hide in pockets in the marshes of Barataria Bay. (April 17) Video provided by AP
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