Plate tectonics

The discovery of the Great Global Rift in the mid-Atlantic ocean highlighted the existence of tectonic plates. Plate tectonics explains the structure of Earth's outer shell and the movement of large plates that cause earthquakes and volcanoes.
 Maurice Ewing, Bruce Charles Heezen United States 1953 Plate tectonics

The discovery of the Great Global Rift in the mid-Atlantic ocean highlighted the existence of tectonic plates. Plate tectonics explains the structure of Earth's outer shell and the movement of large plates that cause earthquakes and volcanoes.