List of tectonic plates in the context of Density

Determining the boundaries between the continents is generally a matter of geographical convention and consensus. Several slightly different conventions are in use. The number of continents is most commonly considered seven (in English-speaking countries) but may range as low as four when Afro-Eurasia and the Americas are both considered as single continents. An island can be considered to be associated with a given continent by either lying on the continent's adjacent continental shelf (e.g. Singapore, the British Isles) or being a part of a microcontinent on the same principal tectonic plate (e.g. Madagascar and Seychelles). An island can also be entirely oceanic while still being associated with a continent by geology (e.g. Bermuda, the Australian Indian Ocean Territories) or by common geopolitical convention (e.g. Ascension Island, the South Sandwich Islands). Another example is the grouping into Oceania of the Pacific Islands with Australia and Zealandia.

There are three overland boundaries subject to definition:

The Arabian plate is a minor tectonic plate in the Northern and Eastern Hemispheres.

It is one of the three continental plates (along with the African and Indian plates) that have been moving northward in geological history and colliding with the Eurasian plate. This collision is resulting in a mingling of plate pieces and mountain ranges extending in the west from the Pyrenees, crossing Southern Europe to Iranian plateau, forming the Alborz and the Zagros Mountains, to the Himalayas and ranges of Southeast Asia.

The Adriatic or Apulian plate is a small tectonic plate carrying primarily continental crust that broke away from the African plate along a large transform fault in the Cretaceous period. The name Adriatic plate is usually used when referring to the northern part of the plate. This part of the plate was deformed during the Alpine orogeny, when the Adriatic/Apulian plate collided with the Eurasian plate.

The Adriatic/Apulian plate is thought to still move independently of the Eurasian plate in NNE direction with a small component of counter-clockwise rotation. The fault zone that separates the two is the Periadriatic Seam that runs through the Alps. Studies indicate that in addition to deforming, the Eurasian continental crust has actually subducted to some extent below the Adriatic/Apulian plate, an unusual circumstance in plate tectonics. Oceanic crust of the African plate is also subducting under the Adriatic/Apulian plate off the western and southern coasts of the Italian Peninsula, creating a berm of assorted debris which rises from the seafloor and continues onshore. This subduction is also responsible for the volcanic interactions of southern Italy.

A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.

On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes resulting from divergent tectonic activity are usually non-explosive whereas those resulting from convergent tectonic activity cause violent eruptions. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift, the Wells Gray-Clearwater volcanic field, and the Rio Grande rift in North America. Volcanism away from plate boundaries most likely arises from upwelling diapirs from the core–mantle boundary called mantle plumes, 3,000 kilometres (1,900 mi) deep within Earth. This results in hotspot volcanism or intraplate volcanism, in which the plume may cause thinning of the crust and result in a volcanic island chain due to the continuous movement of the tectonic plate, of which the Hawaiian hotspot is an example. Volcanoes are usually not created at transform tectonic boundaries where two tectonic plates slide past one another.

The African plate, also known as the Nubian plate, is a major tectonic plate that includes most of the continent of Africa (except for its easternmost part) and the adjacent oceanic crust to the west and south. It also includes a narrow strip of Western Asia along the Mediterranean Sea, including much of Israel and Lebanon. It is bounded by the North American plate and South American plate to the west (separated by the Mid-Atlantic Ridge); the Arabian plate and Somali plate to the east; the Eurasian plate, Aegean Sea plate and Anatolian plate to the north; and the Antarctic plate to the south.

Between 60 million years ago and 10 million years ago, the Somali plate began rifting from the African plate along the East African Rift. Since the continent of Africa consists of crust from both the African and the Somali plates, some literature refers to the African plate as the Nubian plate to distinguish it from the continent as a whole.

The Eurasian plate is a tectonic plate that includes most of Eurasia (a landmass consisting of the traditional continents of Asia and Europe), with the notable exceptions of the Arabian Peninsula, the Indian subcontinent, and the area east of the Chersky Range in eastern Siberia. It also includes oceanic crust extending westward to the Mid-Atlantic Ridge and northward to the Gakkel Ridge.

The Indian plate (or India plate) is a minor tectonic plate straddling the equator in the Eastern Hemisphere. Originally a part of the ancient continent of Gondwana, the Indian plate broke away from the other fragments of Gondwana 100 million years ago and began moving north, carrying Insular India with it. It was once fused with the adjacent Australian plate to form a single Indo-Australian plate, but recent studies suggest that India and Australia may have been separate plates for at least 3 million years. The Indian plate includes most of modern South Asia (the Indian subcontinent) and a portion of the basin under the Indian Ocean, including parts of South China, Indonesian islands, and extending up to but not including Ladakh, Kohistan, and Balochistan in Pakistan.

The Virgin Islands (Spanish: Islas Vírgenes) is an archipelago between the North Atlantic Ocean and northeastern Caribbean Sea, located to the immediate east of the main island of Puerto Rico. It generally forms part of the Leeward Islands of the Lesser Antilles in the West Indies of the Caribbean region.

Geologically separated from the Lesser Antilles by the Anegada Passage and from the Greater Antilles by the Mona passage, all the islands except for Saint Croix lie on the same carbonate platform and insular shelf, known as the Puerto Rico Bank, and same tectonic plate, known as the Puerto Rico–Virgin Islands microplate.

The Okhotsk plate is a minor tectonic plate covering the Kamchatka Peninsula, Magadan Oblast, and Sakhalin Island of Russia; Hokkaido, Kantō and Tōhoku regions of Japan; the Sea of Okhotsk, as well as the disputed Kuril Islands.

Japan's principal fault system is the zone where the Amur plate, the Eastern edge of the Eurasian plate, meets the Okhotsk plate, sometimes considered the Western edge of the North American plate.