The Midcontinent Rift is a giant tear that formed in what is now the U.S. Midwest 1.1 billion years ago. Nicknamed North America's "broken heart," it is filled with solidified magma and lava.

Earth’s continents may look fixed on a globe, but they’ve been drifting, splitting and reforming over billions of years – and ...

Note: Map shows the area with a shake intensity of 4 or greater, which U.S.G.S. defines as “light,” though the earthquake may be felt outside the areas shown. All times on the map are Iran time.