The Great Midwest Earthquake of 1811
Two hundred years ago, a series of powerful temblors devastated what is now Missouri. Could it happen again?
- By Elizabeth Rusch
- Smithsonian magazine, December 2011, Subscribe
(Page 2 of 2)
The Chirp started pinging, five times every second. The air gun blasted every seven seconds. When data from the microphones reached the computers onboard, they beeped. Ping, ping, ping, ping, Boom!, beep. The racket would continue for eight hours as the boat floated ten miles downriver.
Over the past three years, Magnani has used these tools to map the ground below the river in the New Madrid Seismic Zone, a fault system stretching about 150 miles from Cairo, Illinois, to Marked Tree, Arkansas. It’s the most active seismic area in the United States east of the Rockies, with about 200 small quakes a year.
Magnani’s most startling discovery came south of the seismic zone: two faults, one near Memphis, both active in the past 10,000 years. Other researchers have recently identified faults near Commerce, Missouri, and other places outside the New Madrid Seismic Zone that have been active in the past few thousand to millions of years, suggesting that the middle of the country is less stable than it seems.
Geologists have long blamed the New Madrid earthquakes on the Reelfoot Rift, a 500-million-year-old area of weakness in the crust. But the newfound faults lie outside the rift. “Maybe the reason we haven’t been able to solve the mystery of the New Madrid earthquakes is that we’ve been too focused on New Madrid,” Magnani says. “Maybe earthquake activity moves around systematically over time.”
Tuttle has begun a four-year project to date sand blows inside and outside the New Madrid Seismic Zone. “We’ve got to get a solid understanding of what large earthquakes happened where and when,” she says. That’s the best way to estimate the hazard to the Midwest and its millions of people and countless highways, bridges, skyscrapers and crumble-prone brick buildings.
The U.S. Geological Survey estimates that the risk of another New Madrid-scale catastrophe in the next 50 years is about 7 to 10 percent. The risk of a smaller, though still devastating, 6.0 earthquake in the next 50 years is 25 to 40 percent. Ongoing research should help identify which areas are most in danger.
“We need a broader, yet clearer picture of all the networks of faults that have been active in the region,” says Magnani. “We need to find out how big they are and their underlying structures. That’s the only way we can hope to understand intraplate earthquakes—and ultimately keep people safe.”
Elizabeth Rusch wrote about extracting energy from ocean waves for Smithsonian.
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Comments (4)
I just love all the colorful stories mixed all in with the facts of these events.
There is, however, another analysis of what had occurred. Although this may or may not have already been a seismic region, there has been recently discovered evidence to prove that The New Madrid Earthquakes of 1811-12 were actually the result of a meteor impact to Northern Mississippi coming from the dust tail of Comet C/1811 F1.
As unbelievable as this may sound the facts will cinvince. Read more on this quite amazing story at www.wix.com/koolkreations/kalopins-legacy ,documents and links, "A Few Comments on 1811" or just search "Kalopins Legacy"
Posted by Kalopin on April 19,2012 | 07:01 PM
Thanks for these interesting details about the paleoseismology of the New Madrid area.
If you're interested in more details about the 1811-1812 earthquakes, you'll enjoy this collection of first-person accounts of the earthquake: http://history.hanover.edu/texts/1811/Web/Topic-Earthquake.html
The fall and winter of 1811-1812 was an exciting time, with the earthquake, a comet, the Battle of Tippecanoe, and the first steamboat journey down the Ohio and Mississippi Rivers. You can read about all these things here: http://history.hanover.edu/texts/1811
Posted by Sarah McNair Vosmeier on December 6,2011 | 12:16 PM
I wonder if the earthquake that occurred around 1450 AD had any bearing of the demise and disappearance of the Mississippian Culture in the same area. Although the Mississippian Culture was already in decline, possibly due to the effects of the Little Ice Age and other stress factors, could the earthquake have been the proverbial straw that broke the camel’s back, and caused the Native population to disperse?
Posted by Wayne Stevenson on November 29,2011 | 08:37 AM
When Techumseh, the Shawnee chief, failed to get his mother's tribe to join his proposed confederacy, he proclaimed angrily, "I will stamp my foot and all your lodges will fall to the ground!" Almost immediately afterward the New Madrid earthquake occurred. He was as good as his word, or so it seemed!
Posted by Robert Nicklas on November 25,2011 | 09:00 AM