Featured Research

from universities, journals, and other organizations

Seismic Wave Speed In The Lower Mantle

Date:
November 30, 2006
Source:
American Geophysical Union
Summary:
Seismic wave speeds in Earth's lower mantle are governed by the elastic properties of the minerals ferropericlase and silicate perovskite. Therefore, knowing the velocity of sound though these minerals at high pressures and temperatures is essential to understanding properties of the lower mantle.

Seismic wave speeds in Earth's lower mantle are governed by the elastic properties of the minerals ferropericlase and silicate perovskite. Therefore, knowing the velocity of sound though these minerals at high pressures and temperatures is essential to understanding properties of the lower mantle.

However, experimental studies of ferropericlase have been restricted to pressures below about 20 gigapascals, which is insufficient to model the change in the electron spin configuration of iron known to occur within the lower mantle pressures.

Past studies, using x-ray diffraction to produce the needed high pressures, showed increases in bulk modulus and bulk sound velocity for ferropericlase as pressure increased.

In this study, Lin et al. used the nuclear resonance inelastic x-ray scattering technique to measure compressional and shear wave velocities and the shear modulus of ferropericlase at pressures above and below the threshold for iron electron spin pairing changes.

The authors noted a dramatic jump in sound velocities across this transition as pressure increased. They suggest that models of seismic wave speed in the lower mantle be revised to reflect this result.

Title: Sound velocities of ferropericlase in the Earth's lower mantle

Authors: Jung-Fu Lin and Choong-Shik Yoo: Lawrence Livermore National Laboratory, Livermore, California, U.S.A.; Steven D. Jacobsen: Geophysical Laboratory, Carnegie Institute of Washington, Washington D.C., U.S.A.; Department of Geological Sciences, Northwestern University, Evanston, Illinois, U.S.A.; Wolfgang Sturhahn and Jiyong Zhao: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, U.S.A.; Jennifer M. Jackson: Geophysical Laboratory, Carnegie Institute of Washington, Washington D.C., U.S.A.; now at Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, U.S.A.

Source: Geophysical Research Letters (GRL) paper 10.1029/2006GL028099, 2006


Story Source:

The above story is based on materials provided by American Geophysical Union. Note: Materials may be edited for content and length.


Cite This Page:

American Geophysical Union. "Seismic Wave Speed In The Lower Mantle." ScienceDaily. ScienceDaily, 30 November 2006. <www.sciencedaily.com/releases/2006/11/061128083438.htm>.
American Geophysical Union. (2006, November 30). Seismic Wave Speed In The Lower Mantle. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2006/11/061128083438.htm
American Geophysical Union. "Seismic Wave Speed In The Lower Mantle." ScienceDaily. www.sciencedaily.com/releases/2006/11/061128083438.htm (accessed April 23, 2014).

Share This



More Earth & Climate News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

UN Joint Mission Starts Removing Landmines in Cyprus

UN Joint Mission Starts Removing Landmines in Cyprus

AFP (Apr. 23, 2014) — The UN mission in Cyprus (UNFICYP) led a mine clearance demonstration on Wednesday in the UN-controlled buffer zone where demining operations are being conducted near the Cypriot village of Mammari. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
California Drought Is Good News for Gold Prospectors

California Drought Is Good News for Gold Prospectors

AFP (Apr. 22, 2014) — For months California has suffered from a historic drought. The lack of water is worrying for farmers and ranchers, but for gold diggers it’s a stroke of good fortune. With water levels low, normally inaccessible areas are exposed. Duration: 01:57 Video provided by AFP
Powered by NewsLook.com
Raw: MN Lakes Still Frozen Before Fishing Opener

Raw: MN Lakes Still Frozen Before Fishing Opener

AP (Apr. 22, 2014) — With only three weeks until Minnesota's fishing opener, many are wondering if the ice will be gone. Some of the Northland lakes are still covered by up to three feet of ice, causing concern that just like last year, the lakes won't be ready. (April 22) Video provided by AP
Powered by NewsLook.com
Scientists Warn Of Likely El Niño Event This Year

Scientists Warn Of Likely El Niño Event This Year

Newsy (Apr. 22, 2014) — With Pacific ocean water already showing signs of warming, the NOAA says there's about a 66 percent chance the event will begin before November. 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:
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