Featured Research

from universities, journals, and other organizations

Interpreting Images Of Earth's Interior

Date:
December 15, 1999
Source:
University Of Michigan
Summary:
University of Michigan researchers unveiled a model that relates seismic velocity differences to properties of the mantle.

SAN FRANCISCO --- Over the last two decades, scientists have generated many pictures of Earth's interior by mapping the behavior of seismic waves, those waves of energy that shake the ground during earthquakes. These seismic images show some areas where waves travel faster than average and some where they travel more slowly through the mantle---a plastic-like layer between Earth's crust and core that flows under pressure, lifting or lowering features on the surface.

Interpreting exactly what such differences in "seismic velocity" mean has been a challenge, says Carolina Lithgow-Bertelloni, assistant professor of geological sciences at the University of Michigan. But such understanding is essential to knowing "how the mantle has evolved, how it works dynamically, and what we would expect to happen at Earth's surface as a result," she explains.

In an invited presentation to the American Geophysical Union today, Lithgow-Bertelloni and Lars Stixrude, U-M assistant professor of geological sciences, unveiled a model that relates seismic velocity differences to properties of the mantle. Previous models had assumed that the speed at which seismic waves travel through a particular region in the mantle depends only on the temperature of that region. But Lithgow-Bertelloni and Stixrude reasoned that other factors, such as chemical composition and physical structure of the minerals in the region also contribute.

Preliminary results of work based on their model show that phase transitions---changes in the crystal structure of minerals that result from pressure and temperature changes inside Earth---can suddenly speed up or slow down plate movement at Earth's surface. Such plate movement causes mountain-building, earthquakes and volcanoes.

"While this is a new and exciting result, even more surprising is the fact that when we converted the velocity differences of some seismic models to temperature, the results suggested temperatures high enough to cause melting in some regions of the Earth," says Lithgow-Bertelloni. "One such region that we found down to a depth of 200-600 km is right under the East African rift and might possibly be the source of the volcanism in the area." The next step will be to learn how much of the material has melted and to determine its composition, she adds. Comparing its composition to rocks at the surface will help confirm that the melting is responsible for the volcanic activity.


Story Source:

The above story is based on materials provided by University Of Michigan. Note: Materials may be edited for content and length.


Cite This Page:

University Of Michigan. "Interpreting Images Of Earth's Interior." ScienceDaily. ScienceDaily, 15 December 1999. <www.sciencedaily.com/releases/1999/12/991214113030.htm>.
University Of Michigan. (1999, December 15). Interpreting Images Of Earth's Interior. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/1999/12/991214113030.htm
University Of Michigan. "Interpreting Images Of Earth's Interior." ScienceDaily. www.sciencedaily.com/releases/1999/12/991214113030.htm (accessed September 20, 2014).

Share This



More Earth & Climate News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Climate Change Rally Held in India Ahead of UN Summit

Climate Change Rally Held in India Ahead of UN Summit

AFP (Sep. 20, 2014) Some 125 world leaders are expected to commit to action on climate change at a UN summit Tuesday called to inject momentum in struggling efforts to tackle global warming. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com
Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) 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:
from the past week

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