Featured Research

from universities, journals, and other organizations

Why Earthquake Waves Spread Unevenly

Date:
April 14, 2009
Source:
Helmholtz Association of German Research Centres
Summary:
Propagation of earthquake waves within the Earth is not uniform. Experiments indicate that the velocity of shear waves in Earth's lower mantle between 660 and 2900 km depth is strongly dependent on the orientation of ferropericlase.

Propagation of earthquake waves within the Earth is not uniform. Experiments indicate that the velocity of shear waves (s-waves) in Earth's lower mantle between 660 and 2900 km depth is strongly dependent on the orientation of ferropericlase.

In the latest issue of "Science" (Vol. 325, 10.04.2009), researchers from the German Research Center for Geosciences GFZ, the Karlsruhe Institute of Technology, the University of Bayreuth, and Arizona State University report unexpected properties of ferropericlase, which is presumably the second most abundant mineral of the lower mantle.

"The dependence of wave velocity on direction increases significantly at a pressure of about 50 Giga-Pascal, corresponding to approximately 1300 km depth. This is caused by a change in electronic arrangement of the iron ions in ferropericlase" explains Hauke Marquardt from GFZ. In addition, flow in the lower mantle results in a preferred mineral orientation; this causes the detectable non-uniform propagation of earthquake waves. This flow is the driving force of tectonic plate movements, formation of mountains, earthquakes, and volcanic activities and therefore, strongly affects our life on Earth's surface.

Because the deep interior of our planet is not accessible to direct observations, the researchers simulate the conditions of Earth's interior by generating the extreme pressures in their laboratory. Diamond anvil cells are used at GFZ to perform the high-pressure experiments, which are complemented by X-ray diffraction experiments at "Diamond Light Source" in Didcot, UK.

These new findings are of practical importance: Only if we know the properties of the materials that constitute the deep Earth, we can derive information about its internal flow from the non-uniform propagation of earthquake waves. This can help to better understand plate tectonic processes.


Story Source:

The above story is based on materials provided by Helmholtz Association of German Research Centres. Note: Materials may be edited for content and length.


Cite This Page:

Helmholtz Association of German Research Centres. "Why Earthquake Waves Spread Unevenly." ScienceDaily. ScienceDaily, 14 April 2009. <www.sciencedaily.com/releases/2009/04/090411080807.htm>.
Helmholtz Association of German Research Centres. (2009, April 14). Why Earthquake Waves Spread Unevenly. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2009/04/090411080807.htm
Helmholtz Association of German Research Centres. "Why Earthquake Waves Spread Unevenly." ScienceDaily. www.sciencedaily.com/releases/2009/04/090411080807.htm (accessed September 30, 2014).

Share This



More Earth & Climate News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
Seismic Activity Halts Recovery at Japan Volcano

Seismic Activity Halts Recovery at Japan Volcano

AP (Sep. 30, 2014) Rescuers were forced to suspend plans to recover at least two dozen bodies from near the summit of Mount Ontake in central Japan on Tuesday after increased seismic activity raised concern about the possibility of another eruption. (Sept. 30) Video provided by AP
Powered by NewsLook.com
Dolphins Might Use Earth's Magnetic Field As A GPS

Dolphins Might Use Earth's Magnetic Field As A GPS

Newsy (Sep. 30, 2014) A study released Monday suggests dolphins might be able to sense the Earth's magnetic field and possibly use it as a means of navigation. Video provided by Newsy
Powered by NewsLook.com
How To Battle Stink Bug Season

How To Battle Stink Bug Season

Newsy (Sep. 30, 2014) Homeowners in 33 states grapple with stink bugs moving indoors at this time of year. Here are a few tips to avoid stink bug infestations. 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