Those who think that earthquakes are strictly a California phenomenon might be amazed to learn that the most powerful earthquake in recorded American history occurred in the middle of the country near New Madrid (pronounced MAD-rid), Missouri. Between December 16, 1811, and February 7, 1812, about 2,000 tremors shook southeastern Missouri and adjacent parts of Arkansas, Illinois, and Tennessee. The largest of these earthquakes is thought to have had a magnitude of 8.8 on the Richter scale, making it one of the most massive ever recorded.

Witnesses reported shocks so violent that trees 6 feet (2 meters) thick were snapped like matchsticks. More than 150,00 acres (60,000 ha) of forest were flattened. Fissures several yards wide and many miles long split the earth. Geysers of dry sand or muddy water spouted into the air. A trough 150 miles (242 km) long, 40 miles (64 km) wide, and up to 30 feet (9 m) deep formed along the fault line. The...