Divergent Boundary Map

A divergent boundary is where two tectonic plates move apart and new crust forms in the gap between them.

Data source: PB2002 plate model, Bird (2003), converted by Hugo Ahlenius, Nordpil, ODC-By 1.0. Download: CSV .

Last updated 11 October 2026

What is a divergent boundary?

At a divergent boundary two plates spread apart. Hot rock rises from the mantle into the gap, cools and becomes new crust. Most divergent boundaries run along the crest of mid-ocean ridges , which NOAA describes as one connected mountain range nearly 65,000 km long. On land the same process opens a rift .

The Mid-Atlantic Ridge is the classic example. USGS gives a spreading rate of about 2.5 cm a year there, or 25 km in a million years, slow on a human scale but enough to open the whole Atlantic over the past 100 to 200 million years. Iceland straddles the ridge, so it can be seen on land: rifting at Krafla in the north moved the ground apart by about 7 m between 1975 and 1984.

In East Africa a continent is splitting. USGS points to the triple junction where the Red Sea, the Gulf of Aden and the East African Rift meet, and notes the rift may one day flood and become a new ocean. PB2002 splits this type into ocean spreading ridges and continental rifts, shown in two line styles on the map.

How the three types compare

The three plate boundary types, PB2002 totals
Type	Plates move	Crust	Length (km)	Mean speed (mm/yr)
Divergent	Apart	Made	94,840	38.2
Convergent	Together	Destroyed or crumpled	91,765	44.7
Transform	Side by side	Neither made nor destroyed	73,959	34.9

Data source: PB2002 plate model, Bird (2003), converted by Hugo Ahlenius, Nordpil, ODC-By 1.0.

Key facts

PB2002 maps 94,840 km of divergent boundary, 36% of all plate boundaries. Bird (2003)
Oceanic spreading ridges (OSR) make up 67,367 km, with a mean speed of 46.6 mm/yr.
Continental rift boundarys (CRB) make up 27,473 km, with a mean speed of 17.6 mm/yr.
87 pairs of plates meet along a divergent boundary. The longest shared stretch is between the North American and Eurasian plates: 8,687 km.
The fastest divergent step is between the Juan Fernandez and Pacific plates near 32°S, 112°W: 202.1 mm/yr (20.2 cm/yr).

Plate pairs on divergent boundaries

The plates that share the most divergent boundary, by length. Speed is the relative velocity across the boundary , averaged over its length. Plate names link to their pages where we have one.

Top plate pairs by divergent boundary length
Plates	Length (km)	Mean speed (mm/yr)	Classes
North American and Eurasian	8,687	14.6	CRB, OSR
African and South American	8,169	31.9	OSR
Australian and Antarctic	7,457	67.7	OSR
Pacific and Antarctic	5,426	75.8	OSR, CRB
Somali and African	4,947	3.7	CRB
Amur and Eurasian	4,019	9.3	CRB
Nazca and Pacific	3,296	140.9	OSR
Somali and Antarctic	3,271	11.4	OSR
North American and African	2,956	22.9	OSR
Somali and Indian	2,487	29.7	OSR
Eurasian and Yangtze	2,479	14.5	CRB
Cocos and Nazca	2,062	53.5	OSR

Data source: PB2002 plate model, Bird (2003), converted by Hugo Ahlenius, Nordpil, ODC-By 1.0.

Longest divergent segments

A segment here is one unbroken run of the same boundary class between the same two plates. The location is the middle of the run.

Longest continuous divergent segments
Plates	Class	Length (km)	Mean speed (mm/yr)	Near
Somali and African	CRB	3,489	3.3	8°S, 32°E
Amur and Eurasian	CRB	2,146	9.5	48°N, 106°E
Eurasian and Yangtze	CRB	1,918	14.2	30°N, 109°E
North American and Eurasian	CRB	1,364	4.2	72°N, 134°E
North American and Eurasian	OSR	1,251	9.5	84°N, 109°E
Okhotsk and Eurasian	CRB	1,148	4.5	60°N, 143°E
African and Arabian	CRB	1,134	12.8	24°N, 36°E
North American and Eurasian	OSR	1,014	15.1	74°N, 9°E
North American and South American	OSR	992	1.9	16°N, 51°W
Amur and Eurasian	CRB	966	9.0	39°N, 126°E

Data source: PB2002 plate model, Bird (2003), converted by Hugo Ahlenius, Nordpil, ODC-By 1.0.

Speeds range from 0.4 mm/yr to 202.1 mm/yr along this type. For every boundary in one view see the plate boundaries map, compare with the other types: convergent and transform , or see how fast plates move on the plate motion map. All plates are on the tectonic plates map.

Print this map Plate boundaries worksheet. Label each boundary type, with an answer key

Glossary

Divergent boundary: Plates pull away from each other and new crust forms between them. Source
Mid-ocean ridge: An underwater mountain range that forms along divergent plate boundaries, where new ocean floor is made. Source
Rift: A valley where the crust is being pulled apart, such as the East African Rift, which may in time become a new ocean. Source
Relative plate velocity: How fast one plate moves compared with its neighbor across a boundary, in millimeters per year. Source

All terms in the glossary

Divergent boundary FAQ

What happens at a divergent boundary?

The plates pull apart. Molten rock rises from the mantle into the gap and cools into new crust. On the ocean floor this builds a mid-ocean ridge; on land it opens a rift valley.

What is an example of a divergent boundary?

The Mid-Atlantic Ridge, where the North American and Eurasian plates and the South American and African plates move apart. Iceland sits right on top of it. In PB2002 the longest divergent pair is North American and Eurasian.

How fast do plates move apart at a divergent boundary?

USGS gives about 2.5 cm a year for the Mid-Atlantic Ridge and over 15 cm a year for the East Pacific Rise near Easter Island. Across all PB2002 divergent boundaries the length-weighted mean is 3.8 cm/yr.

Can a divergent boundary form on land?

Yes. The East African Rift is a divergent boundary on a continent. USGS notes it may in time split Africa and become a new ocean, as the Red Sea and Gulf of Aden already have.

Sources: USGS, Understanding plate motions; NOAA Ocean Exploration, What is the mid-ocean ridge?; Bird (2003) for all lengths and speeds.