Antarctic Plate
The Antarctic Plate is the third-largest of the 52 plates in the PB2002 plate model, covering 58.2 million km² (22.5 million sq mi), or 11.4% of Earth’s surface. Antarctica and the Southern Ocean floor around it.
- Area
- 58.2 million km² (22.5 million sq mi)
- Share of Earth’s surface
- 11.4%
- Speed across the plate
- 0.0 to 2.6 cm a year (0.0 to 1.0 in)
- Direction at its center
- Toward the west
- Length of its edges
- 40,280 km (25,030 mi)
- Neighboring plates
- 10
- Edges by type
- 7% convergent · 51% divergent · 41% transform
- Volcanoes on it
- 27 active in the past ~12,000 years
What happens at its edges
It is ringed almost entirely by spreading ridges, so new sea floor is added along most of its edge. Subduction plays only a small part, near the South Shetland Islands at the tip of the Antarctic Peninsula and along its boundary with the Scotia Plate.
It is one of the slowest-moving plates. Its rotation pole lies close to the plate itself, so near that pole the ground barely moves at all in this frame.
How fast it moves, and which way
At its center (83.6°S, 57.8°E) the Antarctic Plate moves about 0.9 cm (0.4 in) a year toward the west. Because a plate turns around a pole rather than sliding in a straight line, the speed changes across it: from 0.0 cm (0.0 in) a year to 2.6 cm (1.0 in) a year, with an area-weighted average of 1.3 cm a year. That average makes it the 46th fastest of the 52 plates.
These figures are measured against the average motion of all the plates together (the “no-net-rotation” frame), which is how plate speeds are usually quoted. Measured against the Pacific Plate instead, the Antarctic Plate moves about 3.5 cm (1.4 in) a year toward the northwest at its center.
In the model it rotates about a pole at 62.1°N, 117.1°W at 0.231° per million years. The speeds are averages over years to millions of years of measurement; earthquakes move the ground near a boundary in sudden steps instead.
Neighboring plates and boundaries
Its edges run for 40,280 km (25,030 mi): 7% convergent, where plates move together; 51% divergent, where they move apart; and 41% transform, where they slide past each other. It sinks beneath the Scotia Plate, South American Plate and Shetland Plate at subduction zones.
| Neighbor | Shared edge | Boundary types | Relative speed |
|---|---|---|---|
| Australian Plate | 11,150 km (6,930 mi) | Divergent 67% · Transform 33% | 6.8 cm a yearup to 7.2 cm |
| Pacific Plate | 9,170 km (5,700 mi) | Divergent 59% · Transform 41% | 7.3 cm a yearup to 9.5 cm |
| Somali Plate | 5,520 km (3,430 mi) | Divergent 59% · Transform 41% | 1.2 cm a yearup to 1.4 cm |
| Nazca Plate | 3,950 km (2,460 mi) | Transform 67% · Divergent 33% | 5.7 cm a yearup to 5.8 cm |
| African Plate | 3,300 km (2,050 mi) | Transform 55% · Divergent 45% | 1.4 cm a yearup to 1.4 cm |
| Scotia Plate | 3,190 km (1,980 mi) | Convergent 53% · Transform 28% · Divergent 18% | 1.2 cm a yearup to 1.5 cm |
| South American Plate | 2,710 km (1,680 mi) | Transform 52% · Convergent 27% · Divergent 21% | 1.8 cm a yearup to 2.1 cm |
| Shetland Plate | 1,020 km (630 mi) | Divergent 52% · Convergent 43% · Transform 6% | 1.0 cm a yearup to 1.0 cm |
| Juan Fernández Plate | 160 km (100 mi) | Divergent 74% · Transform 25% | 5.3 cm a yearup to 7.4 cm |
| Sandwich Plate | 90 km (60 mi) | Transform 100% | 6.9 cm a yearup to 6.9 cm |
Relative speed is how fast the two plates move against each other along their shared edge, averaged over its length.
Countries and territories on the Antarctic Plate
All 3 lie entirely on this plate. The share is the part of each country’s land on this plate.
- Antarctica all
- French Southern and Antarctic Lands all
- Heard Island and McDonald Islands all
Volcanoes on the Antarctic Plate
The Smithsonian Global Volcanism Program lists 27 volcanoes on this plate that have been active in roughly the past 12,000 years. The most recent eruptions on record:
- Heard Australia, 2026
- Erebus Antarctica, 2026
- McDonald Islands Australia, 2005
- Marion Island South Africa, 2004
- Boomerang Seamount France, 1995
- Buckle Island Antarctica, 1899
Sources
Outline, area, boundary types and motion: Bird, P. (2003), An updated digital model of plate boundaries, Geochemistry Geophysics Geosystems, 4(3), 1027, doi:10.1029/2001GC000252. Released by its author into the public domain (CC0 1.0). Areas are the model’s published figures; speeds, directions, boundary lengths and countries are calculated from its outlines, boundary steps and rotation poles.
Volcanoes: Global Volcanism Program, Smithsonian Institution, Volcanoes of the World (v. 5.4.0). Country outlines: Natural Earth.