Times: two on December 16, 1811, one on January 23, 1812, and one on February 7, 1812

Location: near New Madrid, Louisiana Territory (now Missouri)

Magnitudes: Mw 8.2, 7.8, 8.1 & 8.3

Fault involved: Reelfoot Rift

1,874 recorded earthquakes in all

Created:

• Lake St. Francis & Reelfoot Lake
• Long, low cliffs
• Streams with new waterfalls (2 m high)
• Swamplands uplifted to form aerated soil

This earthquake was about the same size as 1906 SF EQ, but more damaging – Why? Because of the location of the fault. The Reelfoot Rift underlies the Mississippi River Valley - a huge area full of soft, saturated sediments. These sediments amplify the seismic waves, intensifying them and causing more damage.

December 16, 1811, 2:15 a.m.:
M ~7.2 – 8.1

December 16, 1811, 8:15 a.m.:
M ~7.2–8.1

January 23, 1812, 9 a.m.:
M ~7.0–7.8

February 7, 1812, 4:45 a.m.:
M ~7.4–8.0

Reelfoot Rift

750 myo the supercontinent of Rodinia began to break up

Reelfoot Rift is the failed arm of a rift zone that developed when Rodinia broke up

Facts

• Mercalli Intensity X
• Est. M_w 7.3
• 100+ people killed
• Numerous buildings damaged
• or destroyed
• Property damage was
• estimated at $5-$6 million