A transform fault or transform boundary, is a fault along a plate boundary where the motion is predominantly horizontal. It ends abruptly where it connects to another plate boundary, either another transform, a spreading ridge, or a subduction zone. A transform fault is a special case of a strike-slip fault that also forms a plate boundary.
The North American plate is a tectonic plate containing most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of 76 million km2 (29 million sq mi), it is the Earth's second largest tectonic plate, behind the Pacific plate.
The Juan de Fuca plate is a small tectonic plate (microplate) generated from the Juan de Fuca Ridge that is subducting beneath the northerly portion of the western side of the North American plate at the Cascadia subduction zone. It is named after the explorer of the same name. One of the smallest of Earth's tectonic plates, the Juan de Fuca plate is a remnant part of the once-vast Farallon plate, which is now largely subducted underneath the North American plate.
The Gorda plate, located beneath the Pacific Ocean off the coast of northern California, is one of the northern remnants of the Farallon plate. It is sometimes referred to as simply the southernmost portion of the neighboring Juan de Fuca plate, another Farallon remnant.
The Pacific plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million km2 (40 million sq mi), it is the largest tectonic plate.
The Explorer plate is an oceanic tectonic plate beneath the Pacific Ocean off the west coast of Vancouver Island, Canada, which is partially subducted under the North American plate. Along with the Juan de Fuca plate and Gorda plate, the Explorer plate is a remnant of the ancient Farallon plate, which has been subducted under the North American plate. The Explorer plate separated from the Juan de Fuca plate roughly 4 million years ago. In its smoother, southern half, the average depth of the Explorer plate is roughly 2,400 metres (7,900 ft) and rises up in its northern half to a highly variable basin between 1,400 metres (4,600 ft) and 2,200 metres (7,200 ft) in depth.
The Cascadia subduction zone is a 960 km (600 mi) fault at a convergent plate boundary, about 100–200 km (70–100 mi) off the Pacific coast, that stretches from northern Vancouver Island in Canada to Northern California in the United States. It is capable of producing 9.0+ magnitude earthquakes and tsunamis that could reach 30 m (98 ft). The Oregon Department of Emergency Management estimates shaking would last 5–7 minutes along the coast, with strength and intensity decreasing further from the epicenter. It is a very long, sloping subduction zone where the Explorer, Juan de Fuca, and Gorda plates move to the east and slide below the much larger mostly continental North American plate. The zone varies in width and lies offshore beginning near Cape Mendocino, Northern California, passing through Oregon and Washington, and terminating at about Vancouver Island in British Columbia.
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 either side of an active transform fault move in opposite directions; here, strike-slip activity occurs. Fracture zones extend past the transform faults, away from the ridge axis; are usually seismically inactive, although they can display evidence of transform fault activity, primarily in the different ages of the crust on opposite sides of the zone.
The Mendocino triple junction (MTJ) is the point where the Gorda plate, the North American plate, and the Pacific plate meet, in the Pacific Ocean near Cape Mendocino in northern California. This triple junction is the location of a change in the broad tectonic plate motions which dominate the west coast of North America, linking convergence of the northern Cascadia subduction zone and translation of the southern San Andreas Fault system. This region can be characterized by transform fault movement, the San Andreas also by transform strike slip movement, and the Cascadia subduction zone by a convergent plate boundary subduction movement. The Gorda plate is subducting, towards N50ºE, under the North American plate at 2.5–3 cm/yr, and is simultaneously converging obliquely against the Pacific plate at a rate of 5 cm/yr in the direction N115ºE. The accommodation of this plate configuration results in a transform boundary along the Mendocino Fracture Zone, and a divergent boundary at the Gorda Ridge. This area is tectonically active historically and today. The Cascadia subduction zone is capable of producing megathrust earthquakes on the order of MW 9.0.
The Gorda Ridge, is a tectonic spreading center, located roughly 200 kilometres (120 mi) off the northern coast of California and southern Oregon. Running northeast to southwest, the region is roughly 300 kilometres (190 mi) in length. The ridge is broken into three segments: the northern ridge, central ridge, and the southern ridge, which includes the Escanaba Trough.
The Blanco Fracture Zone or Blanco Transform Fault Zone (BTFZ) is a right lateral transform fault zone, which runs northwest off the coast of Oregon in the Pacific Northwest of the United States, extending from the Gorda Ridge in the south to the Juan de Fuca Ridge in the north.
The Queen Charlotte Fault is an active transform fault that marks the boundary of the North American plate and the Pacific plate. It is Canada's right-lateral strike-slip equivalent to the San Andreas Fault to the south in California. The Queen Charlotte Fault forms a triple junction south with the Cascadia subduction zone and the Explorer Ridge. The Queen Charlotte Fault (QCF) forms a transpressional plate boundary, and is as active as other major transform fault systems in terms of slip rates and seismogenic potential. It sustains the highest known deformation rates among continental or continent-ocean transform systems globally, accommodating greater than 50mm/yr dextral offset. The entire approximately 900 km offshore length has ruptured in seven greater than magnitude 7 events during the last century, making the cumulative historical seismic moment release higher than any other modern transform plate boundary system.
The Explorer Ridge is a mid-ocean ridge, a divergent tectonic plate boundary located about 241 km (150 mi) west of Vancouver Island, British Columbia, Canada. It lies at the northern extremity of the Pacific spreading axis. To its east is the Explorer plate, which together with the Juan de Fuca plate and the Gorda plate to its south, is what remains of the once-vast Farallon plate which has been largely subducted under the North American plate. The Explorer Ridge consists of one major segment, the Southern Explorer Ridge, and several smaller segments. It runs northward from the Sovanco Fracture Zone to the Queen Charlotte triple junction, a point where it meets the Queen Charlotte Fault and the northern Cascadia subduction zone.
The Macquarie triple junction is a geologically active tectonic boundary located at 61°30′S161°0′E at which the historic Indo-Australian Plate, Pacific Plate, and Antarctic Plate collide and interact. The term triple junction is given to particular tectonic boundaries at which three separate tectonic plates meet at a specific, singular location. The Macquarie triple junction is located on the seafloor of the southern region of the Pacific Ocean, just south of New Zealand. This tectonic boundary was named in respect to the nearby Macquarie Island, which is located southeast of New Zealand.
The 1,600 kilometres (990 mi) long Macquarie Fault Zone is a major right lateral-moving transform fault along the seafloor of the south Pacific Ocean which runs from New Zealand southwestward towards the Macquarie Triple Junction. It is also the tectonic plate boundary between the Australian plate to the northwest and the Pacific plate to the southeast. As such it is a region of high seismic activity and recorded the largest strike-slip event on record up to 23 May 1989, of at least 8.0
This is a list of articles related to plate tectonics and tectonic plates.
The Pacific Ocean evolved in the Mesozoic from the Panthalassic Ocean, which had formed when Rodinia rifted apart around 750 Ma. The first ocean floor which is part of the current Pacific plate began 160 Ma to the west of the central Pacific and subsequently developed into the largest oceanic plate on Earth.
The Leech River Fault extends across the southern tip of Vancouver Island in British Columbia, Canada, creating the distinctively straight, narrow, and steep-sided valley, occupied by Loss Creek and two reservoirs, that runs from Sombrio Point due east to the Leech River, and then turns southeast to run past Victoria. It is a thrust fault that marks the northernmost exposure of the Crescent Terrane, where basalt of the Metchosin Igneous Complex is dragged under Vancouver Island by the subducting Juan de Fuca plate. About ten kilometres north the nearly parallel San Juan Fault marks the southern limit of rock of the Wrangellia terrane, which underlies most of Vancouver Island. Between these two northeast-dipping thrust faults are the Leech River Complex and the Pandora Peak Unit. These, along with the Pacific Rim Complex further up the coast, are remnants of the Pacific Rim Terrane which was crushed between Wrangellia and Siletzia. The contact between the bottom of Wrangellia and the top of the subducted PRT continues northwest along the coast as the West Coast Fault, and southeast towards Victoria as the Survey Mountain Fault. The Leech River Fault (LRF) extends off-shore towards Cape Flattery, where the Crescent—Pacific Rim contact continues northwest as the Tofino Fault (TF).
The Chile Ridge, also known as the Chile Rise, is a submarine oceanic ridge formed by the divergent plate boundary between the Nazca plate and the Antarctic plate. It extends from the triple junction of the Nazca, Pacific, and Antarctic plates to the Southern coast of Chile. The Chile Ridge is easy to recognize on the map, as the ridge is divided into several segmented fracture zones which are perpendicular to the ridge segments, showing an orthogonal shape toward the spreading direction. The total length of the ridge segments is about 550–600 km.
