Cocos Plate
The Cocos Plate is the 17th-largest of the 52 plates in the PB2002 plate model, covering 2.9 million km² (1.1 million sq mi), or 0.6% of Earth’s surface. The floor of the eastern Pacific off southern Mexico and Central America.
- Area
- 2.9 million km² (1.1 million sq mi)
- Share of Earth’s surface
- 0.6%
- Speed across the plate
- 3.3 to 10.4 cm a year (1.3 to 4.1 in)
- Direction at its center
- Toward the northeast
- Length of its edges
- 8,080 km (5,020 mi)
- Neighboring plates
- 7
- Edges by type
- 36% convergent · 48% divergent · 16% transform
- Volcanoes on it
- 2 active in the past ~12,000 years
What happens at its edges
It sinks beneath Mexico and Central America along the Middle America Trench, which builds the volcanoes of Guatemala, El Salvador, Nicaragua and Costa Rica and causes many of Mexico’s large earthquakes.
It is one of the fastest plates, spreading away from the Pacific Plate along the East Pacific Rise and from the Nazca Plate along the Galápagos Rift.
How fast it moves, and which way
At its center (8.4°N, 94.6°W) the Cocos Plate moves about 7.3 cm (2.9 in) a year toward the northeast. Because a plate turns around a pole rather than sliding in a straight line, the speed changes across it: from 3.3 cm (1.3 in) a year to 10.4 cm (4.1 in) a year, with an area-weighted average of 7.3 cm a year. That average makes it the 7th 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 North American Plate instead, the Cocos Plate moves about 7.9 cm (3.1 in) a year toward the northeast at its center.
In the model it rotates about a pole at 24.2°N, 115.9°W at 1.507° 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 8,080 km (5,020 mi): 36% convergent, where plates move together; 48% divergent, where they move apart; and 16% transform, where they slide past each other. It sinks beneath the North American Plate, Caribbean Plate and Panama Plate at subduction zones.
| Neighbor | Shared edge | Boundary types | Relative speed |
|---|---|---|---|
| Nazca Plate | 3,030 km (1,880 mi) | Divergent 68% · Transform 32% | 5.6 cm a yearup to 6.7 cm |
| Pacific Plate | 2,050 km (1,280 mi) | Divergent 85% · Transform 15% | 10.0 cm a yearup to 12.6 cm |
| North American Plate | 1,710 km (1,060 mi) | Convergent 100% | 6.2 cm a yearup to 7.9 cm |
| Caribbean Plate | 550 km (340 mi) | Convergent 100% | 7.6 cm a yearup to 8.0 cm |
| Panama Plate | 530 km (330 mi) | Convergent 100% | 7.5 cm a yearup to 7.9 cm |
| Galápagos Plate | 110 km (70 mi) | Divergent 100% | 0.9 cm a yearup to 1.1 cm |
| Rivera Plate | 110 km (70 mi) | Convergent 100% | 1.3 cm a yearup to 1.4 cm |
Relative speed is how fast the two plates move against each other along their shared edge, averaged over its length.
Volcanoes on the Cocos Plate
The Smithsonian Global Volcanism Program lists 2 volcanoes on this plate that have been active in roughly the past 12,000 years. The most recent eruptions on record:
- Northern EPR at 10.7°N Seafloor, 2003
- Northern EPR at 17°N Mexico, about 50 BCE
Where the edges are blurred
Parts of this plate lie in the Rivera-Cocos zone, which the model marks as broad belts of deformation rather than sharp plate edges. There the motion between plates is spread over many faults, and a single boundary line is a simplification.
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.