Summary:
- In August 2011, the eastern seaboard of the U.S. was rocked by a magnitude 5.8 earthquake.
- About 5% of earthquakes take place within a plate, away from plate boundaries.
- Intraplate earthquakes happen along zones of weakness.
- The earthquakes may take place along ancient faults or rift zones.
- In 1812, a magnitude 7.5 earthquake struck near New Madrid, Missouri.
- The New Madrid seismic zone is located in the interior of the North American plate (near Missouri, Arkansas, Tennessee, Kentucky, and Illinois)