The Explainer General
Gigantic earthquakes rocked the Midwestern United States between December 16, 1811, and February 7, 1812. A fault in our continent’s stone base runs beneath the Mississippi River near what is now New Madrid, Missouri. Unequal pressures built up on both sides of this fault and the sides slipped to ease the pressure. Whammo—the first of 3 earthquakes from these slips was felt as far away as New York City, Washington, DC, and Charleston, South Carolina.
There were no scientific instruments to measure the New Madrid Quakes in 1812 so geologists have sifted through widespread accounts from old journals and newspapers for data. Putting the accounts together on a map, we know the quakes were felt over an area of 1,930,000 square miles. They earthquakes began with a pair of terrific shocks at 2:15 and 7:15 local time on the morning of December 16, 1811, both measuring 7.2 - 8.1 on the Richter scale. They were followed by a 7.0 - 7.8 quake on January 23, 1812, and a 7.4 - 8.0 event on February 7, 1912.
The quakes were violent, earth-shifting events. There have been even more powerful earthquakes in Alaska and Hawaii, both vulnerable to deep geological pressures, but the New Madrid quakes are the largest to ever occur in the original forty-eight states. Yet little damage or loss of life was reported. The region was then part of Louisiana Territory, sparsely inhabited with small villages and only a few multi-story masonry buildings. We can’t know how many log cabins or small home chimneys were thrown down, or how many Native Americans were affected.
Coincidentally, the first steam paddle-wheeler on the Mississippi, the New Orleans, invented by Robert Fulton, was making its first trip south during the quakes. Land heaves caused massive waves to travel up and down the river. When the little southbound New Orleans met one of these waves it seemed that the great Mississippi was running backward. Some land rose, riverbanks crumbled, some land subsided and formed new lakes. The river’s course was so changed that maps were useless, and the steamboat did a remarkable job of “feeling its way” through the new channels to dock at New Orleans on January 10, 1812.
We’ve come to expect earthquake and volcanic activity around the Pacific “Ring of Fire,” and other hot-spots of geologic shift, but the New Madrid Quake was the product of an unexpected fault in earth’s crust we now call the New Madrid Seismic Zone. And, yes, there is the possibility of similar earthquakes from this zone in the future. The Earth that seems so solid is secretly restless.
Jan Adkins is not only a writer, but also a wonderful illustrator. His personal website is under construction at the moment, but if you would like to find out more about him and see a list of his very well known books, click here.
Adkins is a member of iNK's Authors on Call and is available for classroom programs through Field Trip Zoom, a terrific technology that requires only a computer, wifi, and a webcam. Click here to find out more.
MLA 8 Citation
Adkins, Jan. "Earthquakes on the Mississippi?" Nonfiction Minute, iNK Think Tank, 25 Sept. 2017, www.nonfictionminute.org/the-nonfiction-minute/earthquakes-on-the-mississippi.
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