Earth’s Major Tectonic Plates

(a) Earth’s surface is divided into a dozen or so rigid plates that move relative to one another. The
boundaries of the plates are the scenes of violent seismic and geologic activity, such as earthquakes,
volcanoes, rising mountain ranges, and sinking seafloors. The arrows indicate whether
plates are moving apart (←→), together (→←), or sliding past one another (↑↓).
(b) Rubbing of Two Plates. The San Andreas fault, running up the west coast of North America, formed
because the Pacific Plate is moving northwest along the North American Plate.
(c) The Separation of Two Plates. The plates that carry Egypt and Saudi Arabia are moving
apart, leaving the trench that contains the Red Sea. This view, taken by astronauts in 1966, shows the
northern Red Sea on the right.
(d) The Collision of Two Plates. The plates that carry India and China are colliding. As a result,
the Himalayas are being thrust upward. In this photograph, taken by astronauts in 1968, Mount
Everest is one of the snow-covered peaks near the center.