Featured Research

from universities, journals, and other organizations

New Madrid Fault System, U.S., May Be Shutting Down

Date:
March 20, 2009
Source:
Purdue University
Summary:
The New Madrid fault system does not behave as earthquake hazard models assume and may be in the process of shutting down, a new study shows.

The New Madrid fault system does not behave as earthquake hazard models assume and may be in the process of shutting down, a new study shows.

Related Articles


A team from Purdue and Northwestern universities analyzed the fault motion for eight years using global positioning system measurements and found that it is much less than expected given the 500- to 1,000-year repeat cycle for major earthquakes on that fault. The last large earthquakes in the New Madrid seismic zone were magnitude 7-7.5 events in 1811 and 1812.

Estimating an accurate earthquake threat for the area, which includes parts of Illinois, Indiana, Tennessee, Arkansas and Kentucky, is crucial for the communities potentially affected, said Eric Calais, the Purdue researcher who led the study.

"Our findings suggest the steady-state model of quasi-cyclical earthquakes that works well for faults at the boundaries of tectonic plates, such as the San Andreas fault, does not apply to the New Madrid fault," said Calais, who is a professor of earth and atmospheric sciences. "At plate boundaries, faults move at a rate that is consistent with the rate of earthquakes so that past events are a reliable guide to the future. In continents, this does not work. The past is not necessarily a key to the future, which makes estimating earthquake hazard particularly difficult."

The team determined that the ground surrounding the fault system is moving at a rate of less than 0.2 millimeters per year and there is likely no motion. A paper detailing the work is published in the current issue of the journal Science.

Seth Stein, co-author of the paper, said this surface movement represents energy being stored that could be released as an earthquake.

"Building up energy for an earthquake is like saving money for a big purchase," said Stein, the William Deering Professor of Earth and Planetary Sciences at Northwestern University. "You put money in over a long period of time and then spend it all at once and have to start saving again."

With an earthquake, it is elastic deformation that must be built up. This can be measured using GPS through movements on the surface, he said.

"The slower the ground moves, the longer it takes until the next earthquake, and if it stops moving, the fault could be shutting down," Stein said. "We can't tell whether the recent cluster of big earthquakes in the New Madrid is coming to an end. But the longer the GPS data keep showing no motion, the more likely it seems."

The U.S. Geological Survey-funded study used data recorded at nine GPS antennas mounted in the ground in the earthquake zone.

"GPS technology can measure movement to the thickness of a fishing line," Stein said. "Use of GPS to study earthquakes shows the impact a new technology can have. It lets us see that the world is different than we thought it was."

In the Midwest there are other faults that show no activity today but have evidence of earthquakes occurring within the past 10,000 to 1 million years, Calais said.

"If other faults in the central and eastern U.S. have been active recently, geologically speaking, they could potentially be activated again in the future," he said. "We need to develop a new paradigm for how earthquakes happen at faults that are inside continents."

Calais and Stein are exploring possible explanations for the behavior of faults like the New Madrid. One possibility is that earthquakes in these areas occur in clusters and then migrate to a nearby fault.

"There is the possibility that seismicity migrates with time as earthquakes trigger earthquakes on nearby faults," Calais said. "Geologists studying the seismic history of faults have found that there have been earthquakes on several faults in the central and eastern U.S. and that they seem to produce bursts of earthquakes and then turn off."

The team is doing additional analysis and modeling to study this further.


Story Source:

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


Journal Reference:

  1. Calais et al. Time-Variable Deformation in the New Madrid Seismic Zone. Science, 2009; 323 (5920): 1442 DOI: 10.1126/science.1168122

Cite This Page:

Purdue University. "New Madrid Fault System, U.S., May Be Shutting Down." ScienceDaily. ScienceDaily, 20 March 2009. <www.sciencedaily.com/releases/2009/03/090313145956.htm>.
Purdue University. (2009, March 20). New Madrid Fault System, U.S., May Be Shutting Down. ScienceDaily. Retrieved April 21, 2015 from www.sciencedaily.com/releases/2009/03/090313145956.htm
Purdue University. "New Madrid Fault System, U.S., May Be Shutting Down." ScienceDaily. www.sciencedaily.com/releases/2009/03/090313145956.htm (accessed April 21, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Tuesday, April 21, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Maine Storm Surge Sparks Power Explosions

Raw: Maine Storm Surge Sparks Power Explosions

AP (Apr. 21, 2015) — Police dash cam video shows a series of explosions along the beach in Maine as heavy storm surge soaked electrical transformers. (April 21) Video provided by AP
Powered by NewsLook.com
Searching For The Loch Ness Monster? Try Google Street View

Searching For The Loch Ness Monster? Try Google Street View

Newsy (Apr. 21, 2015) — For the anniversary of the notorious "Surgeon&apos;s Photo" of the Loch Ness monster, Google used Street View to let those online join the search. Video provided by Newsy
Powered by NewsLook.com
Going Ape: Sierra Leone Chimpanzees Hail Ebola Retreat

Going Ape: Sierra Leone Chimpanzees Hail Ebola Retreat

AFP (Apr. 21, 2015) — As money runs out at Tacugama Chimpanzee Sanctuary in Sierra Leone, around 85 chimps are facing homelessness. The centre closed when the Ebola epidemic was ravaging the country but now that closure is beginning to look permanent. Video provided by AFP
Powered by NewsLook.com
Solar Plane Completes 6th Leg of Quest to Circumnavigate Globe

Solar Plane Completes 6th Leg of Quest to Circumnavigate Globe

AFP (Apr. 21, 2015) — Solar Impulse 2 lands in the Chinese city of Nanjing, finishing the sixth stage of its landmark 12-leg quest to circumnavigate the globe powered only by the sun. Duration: 00:42 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