1811-1812 New Madrid Earthquakes

A series of powerful intraplate earthquakes centered near New Madrid, beginning with a shock of estimated moment magnitude 7.2 to 8.2 on 16 December 1811 and followed by further major events in January and February 1812. They remain the most powerful earthquakes recorded in the contiguous United States east of the Rocky Mountains, felt strongly across roughly 50,000 square miles and moderately across nearly a million square miles, far larger than the felt area of the 1906 San Francisco earthquake. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/