Featured Research

from universities, journals, and other organizations

New Way To Monitor Faults May Help Predict Earthquakes

Date:
October 1, 2009
Source:
Carnegie Institution
Summary:
Scientists have found a way to monitor the strength of geologic faults deep in the Earth. This finding could prove to be a boon for earthquake prediction by pinpointing those faults that are likely to fail and produce earthquakes. Until now, scientists had no method for detecting changes in fault strength, which is not measurable at the Earth's surface.

Scientists at the Carnegie Institution have found a way to monitor the strength of geologic faults deep in the Earth. This finding could prove to be a boon for earthquake prediction by pinpointing those faults that are likely to fail and produce earthquakes. Until now, scientists had no method for detecting changes in fault strength, which is not measureable at the Earth's surface.

Related Articles


Paul Silver* and Taka'aki Taira of the Carnegie Institution's Department of Terrestrial Magnetism, with Fenglin Niu of Rice University and Robert Nadeau of the University of California, Berkeley, used highly sensitive seismometers to detect subtle changes in earthquake waves that travel through the San Andreas Fault zone near Parkfield, California, over a period of 20 years. The changes in the waves indicate weakening of the fault and correspond to periods of increased rates of small earthquakes along the fault.

"Fault strength is a fundamental property of seismic zones," says Taira, now at the University of California, Berkeley. "Earthquakes are caused when a fault fails, either because of the build-up of stress or because of a weakening of the fault. Changes in fault strength are much harder to measure than changes in stress, especially for faults deep in the crust. Our result opens up exciting possibilities for monitoring seismic risk and understanding the causes of earthquakes."

The section of the San Andreas Fault near Parkfield, sometimes called the "Earthquake Capital of the World," has been intensively studied by seismologists and is home to a sophisticated array of borehole seismometers called the High-Resolution Seismic Network and other geophysical instruments. Because the area experiences numerous repeated small earthquakes, it is a natural laboratory for studying the physics of earthquakes.

Seismograms from small earthquakes revealed that within the fault zone there were areas of fluid-filled fractures. What caught the researchers' attention was that these areas shifted slightly from time to time. The repeating earthquakes also became smaller and more frequent during these intervals – an indication of a weakened fault.

"Movement of the fluid in these fractures lubricates the fault zone and thereby weakens the fault," says Niu. "The total displacement of the fluids is only about 10 meters at a depth of about three kilometers, so it takes very sensitive seismometers to detect the changes, such as we have at Parkfield."

What caused the fluids to shift? Intriguingly, the researchers noticed that on two occasions the shifts came after the fault zone was disturbed by seismic waves from large, distant earthquakes, such as the 2004 Sumatra-Andaman Earthquake. Pressure from these waves may have been enough to cause the fluids to flow. "So it is possible that the strength of faults and earthquake risk is affected by seismic events on the other side of the world," says Niu.

The paper is published in the October 1 edition of Nature.

*Paul Silver died tragically in an automobile accident in August.


Story Source:

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


Cite This Page:

Carnegie Institution. "New Way To Monitor Faults May Help Predict Earthquakes." ScienceDaily. ScienceDaily, 1 October 2009. <www.sciencedaily.com/releases/2009/09/090930132654.htm>.
Carnegie Institution. (2009, October 1). New Way To Monitor Faults May Help Predict Earthquakes. ScienceDaily. Retrieved March 28, 2015 from www.sciencedaily.com/releases/2009/09/090930132654.htm
Carnegie Institution. "New Way To Monitor Faults May Help Predict Earthquakes." ScienceDaily. www.sciencedaily.com/releases/2009/09/090930132654.htm (accessed March 28, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Saturday, March 28, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Antarctic Ice Is Melting Faster Than Ever

Antarctic Ice Is Melting Faster Than Ever

Newsy (Mar. 27, 2015) A new study of nearly two decades of satellite data shows Antarctic ice shelves are losing more mass faster every year. Video provided by Newsy
Powered by NewsLook.com
Clean-Up Follows Deadly Weather in Okla.

Clean-Up Follows Deadly Weather in Okla.

AP (Mar. 26, 2015) Gov. Mary Fallin has declared a state of emergency for 25 Oklahoma counties after powerful storms rumbled across the state causing one death, numerous injuries and widespread damage. (March 26) Video provided by AP
Powered by NewsLook.com
At Least Four Dead After Floods in Northern Chile

At Least Four Dead After Floods in Northern Chile

Reuters - News Video Online (Mar. 26, 2015) At least four people have been killed by severe flooding in northern Chile after rains battered the Andes mountains and swept into communities below. Rob Muir reports. Video provided by Reuters
Powered by NewsLook.com
Oklahomans "devastated" By Tornado Damage

Oklahomans "devastated" By Tornado Damage

Reuters - US Online Video (Mar. 26, 2015) Buildings and homes lay in ruins and a semi-truck gets flipped following a fierce tornado that left at least one person dead. Rough Cut (no reporter narration). Video provided by Reuters
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