List of fracture zones

Fracture zones are common features in the geology of oceanic basins. Globally most fault zones are located on divergent plate boundaries on oceanic crust. This means that they are located around mid-ocean ridges and trend perpendicular to them. The term fracture zone is used almost exclusively for features on oceanic crust; similar structures on continental crust are instead termed transform or strike slip faults. Some use the term "transform fault" to describe the seismically and tectonically active portion of a fracture zone after John Tuzo Wilson's concepts first developed with respect to the Mid-Atlantic Ridge. The term fracture zone has a distinct geological meaning, but it is also used more loosely in the naming of some oceanic features. Fracture zones are much longer than wide, but may have feature complexity within their width. Not all named fracture zones are active, indeed only the central portion of those still forming usually is, in an area of active transform faulting associated with a mid-ocean ridge. Classic fracture zones remain significant ocean floor features with usually different aged rocks on either side of the fracture zone due to past tectonic processes. Some fracture zones have been created by mid-ocean ridge segments that have been subducted and that part may no longer exist.

Pacific Ocean

Most fracture zones in the Pacific Ocean originate from large mid-ocean ridges such as the East Pacific Rise, Chile Rise and Juan de Fuca Ridge. The plates that host the fractures are Nazca, Pacific, Antarctic, Juan de Fuca and Cocos among others. Fracture zones being subducted under Southern and Central America are generally southwest–northeast oriented reflecting the relative motion of Cocos, Nazca and the Antarctic plates.

Chile Rise

The fracture zones of the Chile Rise trend in a west to east fashion with the most southern ones taking a slightly more southwest to northeast orientation. This non-perpendicular relation to Chile's coast reflects the oblique subduction of Nazca plate under southern Chile. West of Chile rise the fracture zones are hosted in the Antarctic plate. Some fracture zones such as Chile and Valdivia make up large sections of the Nazca-Antarctic plate boundary.

Name	Minimum length in km	Length of transform boundary in km	Position at Ridge
Chile fracture zone
Chiloé fracture zone
Darwin fracture zone
Desolación fracture zone		0
Esmeralda fracture zone		0
Guafo fracture zone
Guambin fracture zone
Madre de Dios fracture zone		0
Mocha fracture zone		0
Taitao fracture zone		0
Tres Montes fracture zone		0
Valdivia fracture zone

East Pacific Rise

The East Pacific Rise includes the Pacific–Antarctic Rise in some usages and in others relates only to the boundaries between the Pacific plate and the Nazca plates which includes the Juan Fernández plate and Easter microplate.

Cocos–Nazca spreading center

Panama fracture zone

Western Pacific

Some of the fracture zones in the western Pacific Ocean are associated with the smaller plate boundaries of the active back-arc basin spreading center of the North Fiji Basin being the Hunter fracture zone and North Fiji fracture zone. The Parece Vela Rift (Parece Vela fracture zone province) is also associated with the back-arc basin of the Parece Vela Basin at the intersection of the Philippine Sea plate and Mariana plate.

South of the Equator

Vening Meinesz fracture zone
Cook fracture zone
Hunter fracture zone
North Fiji fracture zone

North of the Equator

Victoria fracture zone
Central fracture zone
Parece Vela Rift
* Kokugan fracture zone
* Owashi fracture zone
* Ojirowashi fracture zone
* Inuwashi fracture zone
* Konotori fracture zone
* Toki fracture zone
* Tancho fracture zone
* Raicho fracture zone
Ortelius fracture zone
Waghenaer fracture zone
Rat fracture zone

West of East Pacific Rise and [Gulf of California Rift Zone]

Challenger fracture zone
Austral fracture zone
Marquesas fracture zone
Galapagos fracture zone
Clipperton fracture zone
Clarion fracture zone

Juan de Fuca and [Gorda Ridge]s

Surveyor, Molokai, Pioneer and Murray fracture zones shown in the list were created by ridge segments that no longer exist.

Blanco fracture zone
Surveyor fracture zone
Mendocino fracture zone
Pioneer fracture zone
Murray fracture zone
Molokai fracture zone
Sovanco fracture zone

Northeast Pacific

Sedna fracture zone
Sila fracture zone
Aja fracture zone
Cobb fracture zone

Atlantic Ocean

In the Atlantic Ocean most fracture zones originate from the Mid-Atlantic Ridge, which runs from north to south, and are therefore west to east oriented in general. There are about 300 fracture zones, with an average north–south separation of : two for each degree of latitude. Physically it makes sense to group Atlantic fracture zones into three categories:

Small offset: length of transform fault less than
Medium offset: offset over 30 kilometers
Large offset: offset several hundreds of kilometers