The struggle to understand why earthquakes happen in America’s heartland

Enlarge / Top: A view of the downtown Memphis skyline, including the Hernando De Soto bridge which has been retrofitted for earthquakes. Memphis is located around 40 miles from a fault line in the quake-prone New Madrid system. (credit: iStock via Getty Images)

The first earthquake struck while the town was still asleep. Around 2:00 am on Dec. 16, 1811, New Madrid—a small frontier settlement of 400 people on land now located in Missouri—was jolted awake. Panicked townsfolk fled...