Three great quakes
| Date | Estimated magnitude | What happened |
|---|---|---|
| December 16, 1811 | About 7 | Struck at 2 a.m. in northeast Arkansas |
| January 23, 1812 | About 7 | Centered in Missouri's Bootheel |
| February 7, 1812 | About 7 or more | Destroyed the town of New Madrid, Missouri |
Scientists still debate the exact sizes; estimates run from about 7 to 7.5. Thousands of aftershocks followed.
What people saw
The river ran backward
The Mississippi briefly flowed upstream in places
A new lake
Reelfoot Lake formed in northwest Tennessee
Felt far away
Shaking was felt across much of the eastern U.S.
The land changed
Sand blows, sunken land and new waterfalls
Is it still active?
Yes
- Small quakes happen there regularly
- The fault zone sits under Memphis and nearby towns
- Eastern ground carries shaking much farther than in California
What to know
- The USGS estimates a 25-40% chance of a magnitude 6 or larger there in 50 years
- Secure tall furniture and water heaters
- Drop, cover and hold on when shaking starts
Remember
The biggest earthquakes east of the Rockies happened next door to Arkansas and Tennessee.
Tap or press Enter to flip
Answer key
- When did the great New Madrid earthquakes happen?1811-1812Three big quakes from December 1811 to February 1812.
- What did the Mississippi River do?Briefly ran backward in placesWitnesses saw the river flow upstream.
- Which lake was formed by the quakes?Reelfoot LakeReelfoot Lake in northwest Tennessee.
- About how strong were the main quakes?Magnitude 7 or moreEstimates run about 7 to 7.5.
- What should you do when shaking starts?Drop, cover and hold onDrop, cover and hold on is the recommended action.