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29-720: The Gulf of Aden is divided east to west into three distinct regions by large-scale discontinuities, the Socotra, Alula Fartak, and Shukra-El Sheik transform faults. Located in the central region, bounded by the Alula Fartak fault and Shukra-El Sheik fault , is the Aden spreading ridge. The Aden Ridge connects to the Sheba Ridge in the eastern region and to the Tadjoura Ridge in the western region. Due to oblique nature of

58-521: A zigzag pattern. This results from oblique seafloor spreading where the direction of motion is not perpendicular to the trend of the overall divergent boundary. A smaller number of such faults are found on land, although these are generally better-known, such as the San Andreas Fault and North Anatolian Fault . Transform boundaries are also known as conservative plate boundaries because they involve no addition or loss of lithosphere at

87-409: A junction with another plate boundary, while transcurrent faults may die out without a junction with another fault. Finally, transform faults form a tectonic plate boundary, while transcurrent faults do not. Faults in general are focused areas of deformation or strain , which are the response of built-up stresses in the form of compression , tension, or shear stress in rock at the surface or deep in

116-695: A junction with the East Anatolian Fault at the Karliova Triple Junction in eastern Turkey , across northern Turkey and into the Aegean Sea for a length of 1200 −1500 kilometers. It runs about 20 km south of Istanbul . The North Anatolian Fault is similar in many ways to the San Andreas Fault in California. Both are continental transforms with similar lengths and slip rates. The Sea of Marmara near Istanbul

145-588: A smaller section is also present in the Tasman District in the island's northwest. Other examples include: North Anatolian Fault The North Anatolian Fault ( NAF ) ( Turkish : Kuzey Anadolu Fay Hattı ) is an active right-lateral strike-slip fault in northern Anatolia , and is the transform boundary between the Eurasian plate and the Anatolian plate . The fault extends westward from

174-418: A transform fault links a spreading center and the upper block of a subduction zone or where two upper blocks of subduction zones are linked, the transform fault itself will grow in length. [REDACTED] [REDACTED] Constant length: In other cases, transform faults will remain at a constant length. This steadiness can be attributed to many different causes. In the case of ridge-to-ridge transforms,

203-460: 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. Most such faults are found in oceanic crust , where they accommodate the lateral offset between segments of divergent boundaries , forming

232-467: Is an extensional basin similar to the Salton Trough in California, where a releasing bend in the strike slip system creates a pull-apart basin . Since the disastrous 1939 Erzincan earthquake , there have been seven earthquakes measuring over 7.0 in magnitude, each happening at a point progressively further west. Seismologists studying this pattern believe that each earthquake may trigger

261-507: Is being created to change that length. [REDACTED] [REDACTED] Decreasing length faults: In rare cases, transform faults can shrink in length. These occur when two descending subduction plates are linked by a transform fault. In time as the plates are subducted, the transform fault will decrease in length until the transform fault disappears completely, leaving only two subduction zones facing in opposite directions. [REDACTED] [REDACTED] The most prominent examples of

290-435: Is constantly created through the upwelling of new basaltic magma . With new seafloor being pushed and pulled out, the older seafloor slowly slides away from the mid-oceanic ridges toward the continents. Although separated only by tens of kilometers, this separation between segments of the ridges causes portions of the seafloor to push past each other in opposing directions. This lateral movement of seafloors past each other

319-927: Is the San Andreas Fault on the Pacific coast of the United States. The San Andreas Fault links the East Pacific Rise off the West coast of Mexico (Gulf of California) to the Mendocino Triple Junction (Part of the Juan de Fuca plate ) off the coast of the Northwestern United States , making it a ridge-to-transform-style fault. The formation of the San Andreas Fault system occurred fairly recently during

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348-435: Is where transform faults are currently active. Transform faults move differently from a strike-slip fault at the mid-oceanic ridge. Instead of the ridges moving away from each other, as they do in other strike-slip faults, transform-fault ridges remain in the same, fixed locations, and the new ocean seafloor created at the ridges is pushed away from the ridge. Evidence of this motion can be found in paleomagnetic striping on

377-705: The Oligocene Period between 34 million and 24 million years ago. During this period, the Farallon plate , followed by the Pacific plate, collided into the North American plate . The collision led to the subduction of the Farallon plate underneath the North American plate. Once the spreading center separating the Pacific and the Farallon plates was subducted beneath the North American plate,

406-711: The Aden Ridge, it is highly segmented. Along the ridge there are seven transform faults that offset it to the north. Extension of the Gulf of Aden rift system began in the late Eocene – early Oligocene (~35 Ma ago), caused by the northeast escape of the Arabian plate from the African plate at a rate of ~2 cm/yr, and the development of the Afar plume. Extension eventually gave way to seafloor spreading, first initiated near

435-628: The Aden and Sheba ridges can be explained by varying degrees of obliquity. The ocean-continent transition (OCT) of the Sheba ridge formed parallel to the syn-rift structure, whereas the OCT of the Aden ridge formed oblique to the syn-rift structure. The former scenario is more accommodating to oblique spreading and does not require as many transform faults for stability. 14°N 52°E  /  14°N 52°E  / 14; 52 Transform fault A transform fault or transform boundary ,

464-542: The Aden ridge and its neighboring ridges. One likely cause for the segmentation of the Aden ridge is its distance from the Afar plume. The westernmost region of the Gulf, where the Tadjoura Ridge is located, has an anomalously high mantle temperature due to its proximity to the Afar plume. The result of this is higher degrees of melting and magmatism below the ridge, which allows for longer spreading segments without transform faults. The difference in segmentation between

493-470: The Afar Plume. Sauter et al. (2001) proposed that variations in the spacing of spreading cells along ridges is a result of spreading rate; i.e., larger spacing results from slower spreading rates. However, the variation in spreading rates across the Gulf of Aden, 18 mm/yr in the east and 13 mm/yr in the west, is not great enough to explain the significant variation in spreading cell length between

522-472: The Earth's subsurface. Transform faults specifically accommodate lateral strain by transferring displacement between mid-ocean ridges or subduction zones. They also act as the plane of weakness, which may result in splitting in rift zones . Transform faults are commonly found linking segments of divergent boundaries ( mid-oceanic ridges or spreading centres). These mid-oceanic ridges are where new seafloor

551-461: The Earth's surface. Geophysicist and geologist John Tuzo Wilson recognized that the offsets of oceanic ridges by faults do not follow the classical pattern of an offset fence or geological marker in Reid's rebound theory of faulting , from which the sense of slip is derived. The new class of faults, called transform faults, produce slip in the opposite direction from what one would surmise from

580-399: The Gulf of Aden. Currently, the Aden Ridge is undergoing extension at a rate of ~15 mm/yr. Compared to its neighboring ridges, the Aden ridge is much more segmented. The Aden Ridge is broken up by seven transform faults with ridge segments of 10 – 40 km. In contrast, the Sheba Ridge is broken by only three transform faults and the Tadjoura Ridge continues essentially uninterrupted to

609-534: The Owen transform fault ~18 Ma ago. Seafloor spreading then propagated as far west as the Shukra-El Sheik fault at a rate of ~14 cm/yr ~6 Ma ago rifting propagated west of the Shukra-El Sheik fault until terminating at the Afar plume. The Afar plume is believed to have contributed to the initiation of the Aden ridge, due to the flow of hot mantle material being channeled along the thin lithosphere beneath

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638-695: The San Andreas Continental Transform-Fault system was created. In New Zealand , the South Island 's Alpine Fault is a transform fault for much of its length. This has resulted in the folded land of the Southland Syncline being split into an eastern and western section several hundred kilometres apart. The majority of the syncline is found in Southland and The Catlins in the island's southeast, but

667-456: The constancy is caused by the continuous growth by both ridges outward, canceling any change in length. The opposite occurs when a ridge linked to a subducting plate, where all the lithosphere (new seafloor) being created by the ridge is subducted, or swallowed up, by the subduction zone. Finally, when two upper subduction plates are linked there is no change in length. This is due to the plates moving parallel with each other and no new lithosphere

696-442: The fault changes from a normal fault with extensional stress to a strike-slip fault with lateral stress. In the study done by Bonatti and Crane, peridotite and gabbro rocks were discovered in the edges of the transform ridges. These rocks are created deep inside the Earth's mantle and then rapidly exhumed to the surface. This evidence helps to prove that new seafloor is being created at the mid-oceanic ridges and further supports

725-846: The mid-oceanic ridge transform zones are in the Atlantic Ocean between South America and Africa . Known as the St. Paul, Romanche , Chain, and Ascension fracture zones, these areas have deep, easily identifiable transform faults and ridges. Other locations include: the East Pacific Ridge located in the South Eastern Pacific Ocean , which meets up with San Andreas Fault to the North. Transform faults are not limited to oceanic crust and spreading centers; many of them are on continental margins . The best example

754-505: The other continent. In his work on transform-fault systems, geologist Tuzo Wilson said that transform faults must be connected to other faults or tectonic-plate boundaries on both ends; because of that requirement, transform faults can grow in length, keep a constant length, or decrease in length. These length changes are dependent on which type of fault or tectonic structure connect with the transform fault. Wilson described six types of transform faults: Growing length: In situations where

783-444: The seafloor. A paper written by geophysicist Taras Gerya theorizes that the creation of the transform faults between the ridges of the mid-oceanic ridge is attributed to rotated and stretched sections of the mid-oceanic ridge. This occurs over a long period of time with the spreading center or ridge slowly deforming from a straight line to a curved line. Finally, fracturing along these planes forms transform faults. As this takes place,

812-634: The standard interpretation of an offset geological feature. Slip along transform faults does not increase the distance between the ridges it separates; the distance remains constant in earthquakes because the ridges are spreading centers. This hypothesis was confirmed in a study of the fault plane solutions that showed the slip on transform faults points in the opposite direction than classical interpretation would suggest. Transform faults are closely related to transcurrent faults and are commonly confused. Both types of fault are strike-slip or side-to-side in movement; nevertheless, transform faults always end at

841-408: The theory of plate tectonics. Active transform faults are between two tectonic structures or faults. Fracture zones represent the previously active transform-fault lines, which have since passed the active transform zone and are being pushed toward the continents. These elevated ridges on the ocean floor can be traced for hundreds of miles and in some cases even from one continent across an ocean to

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