The tectonic plates are lithospheric plates, the main building block of Earth's crust, including that underneath water bodies. The tectonic plates are in constant motion due to the physical processes that continue to take place in Earth's mantle.
The phenomenon is known as Plate Tectonics and was fundamental in forming our planet Earth's current shape. Earth's surface is currently composed of 2 types of crust - a thin and thick one.
The thinner crust is characteristic primarily for the ocean bottom and is about 5 mi (8 km) thick. The more massive crust, which forms the continents, is up to 25 mi (40 km) thick.
Our planet consists of 7 large tectonic plates. These are: the North American Plate, including North America, the western North Atlantic and Greenland; the South American Plate (South America and the west South Atlantic); the Antarctic Plate (Antarctica and the Southern Ocean); the Eurasian Plate (eastern North Atlantic, Europe and Asia).
The final 3 main tectonic plates are: the African Plate (Africa, the eastern South Atlantic and western Indian Ocean); the Indo-Australian Plate (India, Australia, New Zealand and most of the Indian Ocean); and the Pacific Plate (including the majority of the Pacific Ocean and southern coasts of California).
Besides these 7 major tectonic plates there are 8 secondary plates - the Nazca Plate, Cocos Plate, Caribbean Plate, Arabian Plate, Scotia Plate, Indian Plate, Philippine Sea Plate and Juan de Fuca Plate, as well as a great number of tertiary plates.