The New Madrid Fault, a GLP Exclusive Analysis

The New Madrid Fault

History

The name of the fault comes from the town of New Madrid, MO. At the time of the quakes, it was the largest town on the Mississippi River between St. Louis and Natches, MS. Memphis was founded in 1819, Little Rock in 1821, so at the time, it was the nearest thing to the epicenter with a name people recognized.

Three Main Shocks, One Huge Aftershock

December 16, 1811 - Magnitude ~7.7 2:15am local time, northeast Arkansas
December 17, 1811 - Magnitude ~7.0 7:15am local time, northeast Arkansas
January 23, 1812 - Magnitude ~ 7.5 southeast Missouri
February 7, 1812 - Magnitude ~ 7.7 along Reelfoot Fault Missouri/Tennessee border

1811, December 16, 08:15 UTC Northeast Arkansas - the first main shock
2:15 am local time
Magnitude ~7.7

This powerful earthquake was felt widely over the entire eastern United States. People were awakened by the shaking in New York City, Washington, D.C., and Charleston, South Carolina. Perceptible ground shaking was in the range of one to three minutes depending upon the observers location. The ground motions were described as most alarming and frightening in places like Nashville, Tennessee, and Louisville, Kentucky. Reports also describe houses and other structures being severely shaken with many chimneys knocked down. In the epicentral area the ground surface was described as in great convulsion with sand and water ejected tens of feet into the air (liquefaction).

1811, December 16, 13:15 UTC Northeast Arkansas - the "Dawn" Aftershock
7:15 am local time
Magnitude ~7.0

A large event felt on the East Coast that is sometimes regarded as the fourth principal earthquake of the 1811-1812 sequence. The event is described as "severe" at New Bourbon, Missouri, and was described by boatman John Bradbury, who was moored to a small island south of New Madrid, as "terrible, but not equal to the first". Hough believes that this large aftershock occurred around dawn in the New Madrid region near the surface projection of the Reelfoot fault.

1812, January 23, 15:15 UTC, New Madrid, Missouri
9:15 am local time
Magnitude ~7.5

The second principal shock of the 1811-1812 sequence. It is difficult to assign intensities to the principal shocks that occurred after 1811 because many of the published accounts describe the cumulative effects of all the earthquakes and because the Ohio River was iced over, so there was little river traffic and fewer human observers. Using the December 16 earthquake as a standard, however, there is a general consensus that this earthquake was the smallest of the three principals. The meizoseismal area was characterized by general ground warping, ejections, fissuring, severe landslides, and caving of stream banks.

1812, February 7, 09:45 UTC, New Madrid, Missouri
3:45 am local time
Magnitude ~7.7

The third principal earthquake of the 1811-1812 series. Several destructive shocks occurred on February 7, the last of which equaled or surpassed the magnitude of any previous event. The town of New Madrid was destroyed. At St. Louis, many houses were damaged severely and their chimneys were thrown down. The meizoseismal area was characterized by general ground warping, ejections, fissuring, severe landslides, and caving of stream banks.

source: [link to earthquake.usgs.gov]



Fast Forward 200 years...


Events of August 23, 2011

Colorado -- Tuesday, August 23, 2011 at 05:46:19 UTC (8/22/11, 11:46pm local time)
5.3 quake, depth ~4km
source: [link to earthquake.usgs.gov]
Strongest quake in 40 years in Colorado.

Virginia -- Tuesday, August 23, 2011 at 17:51:04 UTC (8/23/11, 1:51pm local time)
5.8 quake, depth ~6km
source: [link to earthquake.usgs.gov]
Strongest quake in Virginia since 1897. Predictions for this strength of quake in that region are for about six events per 10,000 years. Rare indeed. source: [link to www.washingtonpost.com]

These two events draw an almost perfect straight line through New Madrid's historic epicenters, especially if we account for map distortion due to curvature of the earth. Looking at this map below, we can see that extending the line to the west has it run very near the site of the great San Francisco earthquake of 1906, estimated at 7.8 - 8.3 depending on which study you go by. Coincidence? Perhaps, but it could indicate a trend of large events.

IMAGE: [link to i.imgur.com]

So, we know that there has evidently been some pressure building on the Atlantic slope of the Rockies, as evidenced by the location of the Colorado quake. And we know some pressure has been building on the Atlantic slope of the Appalachians, evidenced by the Virginia quake. It leaves us to wonder how much pressure is stored in the Mississippi valley. Recent seismicity in the entire mid-Great Plains and Ozark region has increased in recent years, with mild quakes even in unlikely places such as North Texas and Oklahoma. Compound the natural tensions with man-made stress such as aquifer depletion and "fracking" from natural gas drilling.

IMAGE: [link to i.imgur.com]

Modern studies have shown little surface evidence for a mechanism for stress-loading in the current geological era, so future events may be very hard to predict for New Madrid if the existing geologic stress is leftover from past climatological and geological eras.
source: [link to geology.com]



Who's in Danger:

Major Cities
Memphis, TN: 646,889
Greater St. Louis, MO metro area: 2,845,298
Greater Nashville, TN metro area: 1,582,264

Mid-sized Cities
Clarksville, TN: 139,929 (home of Ft. Campbell, ~45,000 regular Army)
Evansville, IN: 350,261
Jackson, TN: 65,211
Jonesboro, AR: 67,263

That's over 5 million people without counting the hundreds of small towns in the region. Also at risk is just about anyone living in the 100 year floodplain area of the Mississippi River. If a geologic shift were to cause it to change its course slightly, it could easily wipe away entire small towns that more or less line it from source to mouth.



Fukushima Part 2?

Nuclear plants in the US in relation to Seismic zones
IMAGE: [link to www.greenpeace.org]
source: [link to www.greenpeace.org]
At least 4 nuke plants within 200 miles, a dozen within 300 miles. The 1811 event was felt on the East coast, over 400 miles away. It could be that seismic waves will propagate with more strength farther than they would in other areas of the country, which have mountainous boundaries to slow and deflect the waves. Think of it like tossing a stone into calm water versus choppy water. The waves will propagate with greater strength much farther in calm water.

We only need look at Japan to see what the nightmare potential is for nuclear reactors in seismic areas or flood zones.


I live in the area, what can I do?

Watch for earthquake lights - reported to appear very shortly before seismic events. They've been likened to the appearance of an aurora, from white to bluish, but have also been reported in colors ranging the entire spectrum. Reports indicate them lasting from a few seconds to many minutes, and visible from up to 200 miles from the epicenter. Speculated to be caused by intense electrical fields generated by piezoelectricity, generated by crystals in rock formations under stress, and channeled into the atmosphere by the earth's magnetic field, where the free electrons excite gasses into a glowing plasma state. If this theory is true, the New Madrid area is prime for it, because of the enormous amounts of pure quartz deposited in the Ozark region. [link to en.wikipedia.org]

Prepare an earthquake kit - There are so many preparedness sites on the internet, it would be foolish to go into any detail about it here, but you should at least have emergency water, food, first aid, and blankets ready. See [link to 72hours.org] for an easy to follow disaster prep site.

Have a plan - Even if you are the type who spends your last dime on Ramen noodles and internet service every month with nothing left over for prep supplies, you should have a plan on what to do in the event of a major disaster; where to go, who to meet, how you'll get there in various scenarios, etc. Don't just have a vague idea in your head. Sit down and write it out, look around on the net at other people's published plans to get ideas. It could save you or your family's life to not only have supplies, but have a plan of action as well.

And last but not least, despite all the doom and gloom, don't live your life in anxiety or fear over things you cannot control. You probably don't fret about getting run over crossing the street, and that is much, much more likely to happen than being killed in a major disaster. But disasters do happen, and knowledge is your best defense.

--note to mods, all sources are public domain and cited where copied directly, and paraphrased or rephrased and cited where the info was not clearly public domain. And feel free to put the images inline (please!)

Last Edited by Robot Emotions on 08/24/2011 10:11 PM