Featured Research

from universities, journals, and other organizations

Crackling Noise In Cereal And Magnets Aids Study Of Earthquakes

Date:
June 4, 2001
Source:
University Of Illinois At Urbana-Champaign
Summary:
When Karin Dahmen hears the crackling noise in a bowl of crisped-rice cereal, her thoughts turn to earthquakes. That’s because both the cereal and an earthquake fault zone have something in common: Each responds to an external force with a power law distribution of events of all sizes, independent of microscopic or macroscopic details.

CHAMPAIGN, Ill. — When Karin Dahmen hears the crackling noise in a bowl of crisped-rice cereal, her thoughts turn to earthquakes.

Related Articles


That’s because both the cereal and an earthquake fault zone have something in common: Each responds to an external force with a power law distribution of events of all sizes, independent of microscopic or macroscopic details. By studying such universal behavior, which depends upon just a few basic properties, scientists may better understand the physics of earthquakes.

Dahmen, a physicist at the University of Illinois, initially studied a similar effect – called Barkhausen noise – in magnets. That work was done in collaboration with her thesis adviser, Jim Sethna at Cornell University. "Magnetic materials respond to an external field by changing their magnetization in a series of bursts, or avalanches," she said. "In highly disordered materials, we find small avalanches. But in clean materials, we find huge avalanches that sweep through the material." What all three systems – a bowl of cereal, a reel of magnetic tape and a fault zone – have in common is a competition between interaction and disorder, Dahmen said. "First, there is a slow driving force – such as a magnetic field in magnets or continental drift in earthquakes – and some interaction that promotes the avalanche. Then, there is some disorder that stops the avalanche. This competition between interaction and disorder creates a very broad distribution of avalanche sizes."

Dahmen and her colleagues – Daniel Fisher at Harvard University, Yehuda Ben-Zion at the University of Southern California, Deniz Ertas at Exxon Research and Engineering, and Sharad Ramanathan at Bell Labs – recently took the tools used to study noise in magnets and applied them to earthquake models. The tools, such as mean-field theory and renormalization group techniques, allowed the researchers to examine the interplay between disorder and dynamical effects in earthquakes.

Fault zones with highly irregular geometry display power law statistics over the entire range of observed magnitudes, Dahmen said. Faults with more regular geometry, however, display such distributions only for small events, which typically occur between much larger events that rupture a large fraction of the fault.

"Our model suggests a competition between the earthquake-promoting effect of seismic waves and the earthquake-stopping effect of heterogeneities in the fault plane," said Dahmen, who was to present the team’s findings at the American Geophysical Union Spring Meeting May 29-June 2 in Boston. "In highly heterogeneous faults, dynamical effects can be neglected, and we expect to see the pure power law distribution. But in highly regular faults, the weakening effects of seismic waves become important." Earthquakes that grow larger than a critical size – which depends on the amount of disorder in the fault plane – become unstoppable in the presence of seismic waves, Dahmen said. "These earthquakes then grow to the characteristic runaway event size, in which a large fraction of the fault zone ruptures."


Story Source:

The above story is based on materials provided by University Of Illinois At Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University Of Illinois At Urbana-Champaign. "Crackling Noise In Cereal And Magnets Aids Study Of Earthquakes." ScienceDaily. ScienceDaily, 4 June 2001. <www.sciencedaily.com/releases/2001/06/010604072543.htm>.
University Of Illinois At Urbana-Champaign. (2001, June 4). Crackling Noise In Cereal And Magnets Aids Study Of Earthquakes. ScienceDaily. Retrieved March 4, 2015 from www.sciencedaily.com/releases/2001/06/010604072543.htm
University Of Illinois At Urbana-Champaign. "Crackling Noise In Cereal And Magnets Aids Study Of Earthquakes." ScienceDaily. www.sciencedaily.com/releases/2001/06/010604072543.htm (accessed March 4, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Wednesday, March 4, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Tourists Visit Rare Grey Whales in Mexico

Raw: Tourists Visit Rare Grey Whales in Mexico

AP (Mar. 4, 2015) Once nearly extinct, grey whales now migrate in their thousands to Mexico&apos;s Vizcaino reserve in Baja California, in search of warmer waters to mate and give birth. Tourists flock to the reserve to see the whales, measuring up to 49 feet long. (March 4) Video provided by AP
Powered by NewsLook.com
Raw: Injured Miners Treated After Blast

Raw: Injured Miners Treated After Blast

AP (Mar. 4, 2015) An explosion ripped through a coal mine before dawn Wednesday in war-torn eastern Ukraine, killing at least one miner, officials said. Graphic video of injured miners being treated in a Donetsk hospital. (March 4) Video provided by AP
Powered by NewsLook.com
Australian Museum Shares Terrifying Goblin Shark With the World

Australian Museum Shares Terrifying Goblin Shark With the World

Buzz60 (Mar. 4, 2015) The Australian Museum has taken in its fourth-ever goblin shark, a rare fish with an electricity-sensing snout and &apos;alien-like&apos; jaw. Mike Janela (@mikejanela) takes a look. Video provided by Buzz60
Powered by NewsLook.com
Chile's Villaricca Volcano Calm, Red Alert Remains

Chile's Villaricca Volcano Calm, Red Alert Remains

AFP (Mar. 4, 2015) A red alert continues in the area around southern Chile&apos;s Villarrica volcano, though activity dropped since its eruption overnight on Monday. Duration: 00:40 Video provided by AFP
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