Where it is and what it carries
The North American Plate covers about 55.4 million square kilometers, or 10.9% of Earth’s surface. It holds all of Canada and Greenland, nearly all of the United States (98.9%), most of Mexico (92.7%) and Cuba, and about 10% of Russia in far eastern Siberia. It also includes the western half of the North Atlantic floor and part of the Arctic Ocean.
The plate is a mix of old continental crust and younger oceanic crust. Its core is the Canadian Shield, ancient rock that has stayed stable for billions of years. Around that core sit younger mountain belts: the Appalachians in the east, built during collisions that assembled Pangaea, and the Rocky Mountains and other ranges of the western Cordillera.
What happens at its edges
The longest boundary, 10,767 km, is with the Eurasian Plate. It follows the Mid-Atlantic Ridge north to Iceland and continues into the Arctic as the Gakkel Ridge, one of the slowest spreading ridges on Earth. The average relative speed here is about 1.5 cm/yr. Farther south, the plate spreads from the African Plate at about 2.3 cm/yr, and its boundary with the South American Plate is barely active at about 0.15 cm/yr.
The western edge meets the Pacific Plate along 8,341 km at about 5.6 cm/yr. In California this is the San Andreas transform fault; off British Columbia and southeastern Alaska, the Queen Charlotte Fault; and from southern Alaska west along the Aleutian Islands, the Aleutian Trench, where Pacific seafloor subducts. Between them, the Juan de Fuca Plate sinks beneath the Pacific Northwest at the Cascadia Subduction Zone at about 4 cm/yr.
To the south, the Cocos Plate subducts beneath Mexico and Guatemala at the Middle America Trench at about 6.2 cm/yr, and the small Rivera Plate does the same off Jalisco at about 2 cm/yr. The Caribbean Plate slides east past North America at about 1.7 cm/yr along transform faults through Guatemala, the Cayman Trough and the Puerto Rico Trench. In northeast Asia, the boundary with the Okhotsk Plate moves at only about 0.3 cm/yr.
Earthquakes
The dataset lists 462 earthquakes of magnitude 6.5 or larger on the plate since 1900, 13 of them magnitude 8 or more. Almost all of the largest struck Alaska, where Pacific seafloor subducts beneath the plate. The 1964 Prince William Sound earthquake (M9.2) is the largest ever recorded in North America. Others include the 1965 Rat Islands earthquake (M8.7), the 1946 Unimak Island and 1957 Atka earthquakes (both M8.6) and the 2021 Chignik earthquake (M8.2). In Mexico, the 2017 Tehuantepec earthquake reached M8.2. The Cascadia Subduction Zone has had no great earthquake in the instrumental era, but geologic and historical evidence shows one struck in January 1700.
Volcanoes and hotspots
The plate holds 200 volcanoes in the dataset. Subduction feeds the Aleutian arc (Shishaldin, Great Sitkin), the Cascade Range (Mount St. Helens, which erupted in 1980, and Mount Rainier) and the volcanoes of Mexico and Guatemala, including Popocatepetl, Fuego and Santa Maria. In Iceland, the Reykjanes Peninsula has erupted repeatedly since 2021 as the plates pull apart. Inside the plate, the Yellowstone Caldera sits above a mantle hotspot whose track crosses the Snake River Plain.