The Hunter Fracture Zone is a sinistral (left-lateral) transform faulting

fracture zone A fracture zone is a linear feature on the ocean floor—often hundreds, even thousands of kilometers long—resulting from the action of offset mid-ocean ridge axis segments. They are a consequence of plate tectonics. Lithospheric plates on eit ...

, that to its south is part of a triple junction with the

New Hebrides Trench The New Hebrides Trench is an oceanic trench which extends to over deep in the Southern Pacific Ocean. It lies to the northeast of New Caledonia and the Loyalty Islands, to the southwest of Vanuatu, east of Australia, and south of Papua New Guin ...

, and the

North Fiji Basin The North Fiji Basin (NFB) is an oceanic basin west of Fiji in the south-west Pacific Ocean. It is an actively spreading back-arc basin delimited by the Fiji islands to the east, the inactive Vitiaz Trench to the north, the Vanuatu/New Hebrides ...

Central Spreading Ridge. The Hunter Fracture Zone, with the

Hunter Ridge The Hunter Ridge (previously known as Hunter Island Ridge, Matthew Ridge), is an active volcanic arc oceanic ridge located on the oceanic New Hebrides Plate in the south-west Pacific Ocean extending at least . It defines the south-western limit o ...

, an area with recent volcanic activity to its north, is the southern boundary of the

. This boundary area in the south-western part of the Hunter Fracture Zone is associated with hot subduction, and a unique range of volcanic geochemistry.

Geography

The Hunter Fracture Zone is located to the south and southwest of

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists ...

and starts where the southern part of the

ends due to the increasing obliqueness of convergence lending to more strike slip faulting than subducting. It terminates around the

International Date Line The International Date Line (IDL) is an internationally accepted demarcation on the surface of Earth, running between the South and North Poles and serving as the boundary between one calendar day and the next. It passes through the Pacific O ...

, with the Kadavu Islands immediately to its north. However some earlier work has postulated that the fault structures around

Suva Suva () is the capital and largest city of Fiji. It is the home of the country's largest metropolitan area and serves as its major port. The city is located on the southeast coast of the island of Viti Levu, in Rewa Province, Central Divi ...

on Fiji itself are related and different authors have defined the zone variably.

Seismicity

The western Hunter Fracture Zone is an area of fair shallow seismicity. Large (more than ) earthquakes have occurred in historic times.

Tectonics

It defines part of the plate boundary between the New Hebrides and the Conway Reef Microplate with the Australian Plate, with the rest of the convergence being accommodated by

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

and rifting. The major present subduction and rifting is in an area where the Hunter Ridge is being split that is called the Monzier Rift.. This is active volcanically as part of a separate subduction system to the rest of the

Vanuatu subduction zone The Vanuatu subduction zone (previously called New Hebrides subduction zone) is currently one of the most active subduction zones on earth, producing great earthquakes (magnitude 8.0 or greater), with potential for tsunami hazard to all coastlines ...

that has been called the Matthew and Hunter subduction zone. The Hunter Ridge and Hunter Fracture Zone are the south eastern terminus of the

's subduction and its associated slab edge. From 3 million years ago the southernmost Central Spreading Ridge of the North Fiji Basin propagated southward and has now intersected with the New Hebrides Trench and the Hunter Fracture Zone to form the current triple junction.

References

; Sources * * {{Refend Fracture zones Seismic zones of Oceania Seismic faults of Oceania

Geography

Seismicity

Tectonics

See also

References