Tectonic Plates Map

How to read the map

Red lines are divergent boundaries. Here plates move apart and new crust forms from magma that rises from the mantle. Most run along spreading ridges on the ocean floor, such as the Mid-Atlantic Ridge.

Blue lines are convergent boundaries, where plates move toward each other. Often one plate sinks under the other in a subduction zone, which builds deep trenches, volcanoes and mountain ranges. Around the Pacific, these edges form the Ring of Fire, which USGS calls the most seismically and volcanically active zone in the world.

Green dashed lines are transform boundaries, where two plates slide horizontally past each other. Many short transform faults offset the spreading ridges, which gives the ridges their zig-zag shape. The San Andreas fault in California is a transform boundary on land.

Gray shading shows today's land for reference. Plate edges and coastlines rarely match: most plates carry both continent and ocean floor.

Boundary lengths

Adding up the PB2002 boundary segments gives about 260,564 km of plate boundary. The split by type:

• Divergent (spreading ridge, rift): 94,840 km (36.4%)
• Convergent (subduction, collision): 91,765 km (35.2%)
• Transform (sliding past): 73,959 km (28.4%)

Major plates and microplates

USGS describes the Earth's outer layer as a dozen or more large and small plates. Bird's PB2002 model separates out many of the small ones, which is why this map shows 52. Small plates cluster in plate-boundary zones such as the Mediterranean and Alpine region between the African and Eurasian Plates, where USGS describes a complex boundary zone of microplates. Bird also marks 13 orogens, such as the Alps-Persia-Tibet mountain belt and the Philippine Islands, which his model does not divide into plates.

More maps

See where these plates carried the continents on the Pangea map, or how water moves above them on the ocean currents map.