St. Louis Area Earthquakes

Earthquake history near St. Louis

1. 1811–1812 New Madrid earthquake sequence
2. February 7, 1812 Reelfoot Lake
3. April 18, 2008 Mount Carmel earthquake

New Madrid Seismic Zone

This fault system extends through southeastern Missouri, northeastern Arkansas, and nearby parts of Tennessee and Kentucky. In the winter of 1811–1812, three major earthquakes struck within eight weeks. The USGS estimates magnitudes of 7.5 on December 16, 1811, in northeastern Arkansas, 7.3 on January 23, 1812, in Missouri, and 7.5 on February 7, 1812, along the Reelfoot Fault in Missouri and Tennessee. Large aftershocks followed the main shocks.

Did the Mississippi run backward?

The New Madrid quakes sent waves upstream, making the Mississippi look as though it had reversed course. The February 1812 shock damaged homes and toppled chimneys in St. Louis. Ground sank near Tiptonville, Tennessee, forming Reelfoot Lake.

USGS summary of the 1811–1812 earthquakes

Thebes Gap and other regional faults

Near Cape Girardeau, the Thebes Gap fault area includes the Commerce Fault, English Hill Fault Zone, Happy Hollow Fault, Sassafras Canyon faults, and Albrecht Creek Fault. Farther east, the Fluorspar Area Fault Complex extends across southern Illinois and western Kentucky. USGS researchers also documented faulting along the Ste. Genevieve Fault Zone in southern Illinois.

USGS Thebes Gap report · USGS study of southern Illinois faulting

Wabash Valley Seismic Zone

This zone spans southeastern Illinois and southwestern Indiana. On April 18, 2008, a magnitude 5.2 earthquake near Mount Carmel, Illinois, was felt across a wide area that included Chicago and Atlanta. The USGS received about 40,000 felt reports.

USGS report on the 2008 Illinois earthquake