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fault are fractures in Earth ’s crust where rocks on either side of the crack have slid past each other .
Sometimes the crevice are tiny , as thin as hair , with scantily noticeable movement between the rock layers . But faults can also be hundreds of miles long , such as theSan Andreas Faultin California and the Anatolian Fault in Turkey , both of which are visible from place .
An image of the San Andreas fault in California. The San Andreas fault is a strike-slip fault.
Three types of faults
There are three sort of faults : strike - slip , normal and thrust ( reverse ) faults , say Nicholas van der Elst , a seismologist at Columbia University ’s Lamont - Doherty Earth Observatory in Palisades , New York . Each type is the consequence of different force pushing or pulling on the crust , cause rocks to slide up , down or past each other .
" Each describes a different form of relative motion , " van der Elst said .
Strike - slip faultsoccur where rock candy are slide past each other horizontally , with little to no upright movement . Both the San Andreas and Anatolian fault that ruptured during the February 2023 earthquake in Turkey are strike - slip .
Faults are categorized into three general groups based on the sense of slip or movement.
Normal faultscreate space . Two blocks of crust take out aside , stretch the crust into a valley . The Basin and Range Province in North America and the East African Rift Zone are two well - known regions where normal faults are circularise apart Earth ’s insolence .
Reverse faults , also call thrust fault , slide one city block of crust on top of another . These faults are commonly found in collisions zone , where architectonic plates drive up mountain ranges such as the Himalayas and the Rocky Mountains .
Strike - slip faults are normally perpendicular , while normal and reverse fault are often at an angle to the Earth ’s control surface . The different styles of faulting can also combine in a single event , with one fault moving in both a perpendicular and strike - slip motion during anearthquake .
All faults are related to the movement of Earth ’s tectonic plates . The big shift label the boundary between two plate .
Seen from above , these look as broad zones of deformation , with many faults braided together . " Plate bound are always grow and changing , so these faults develop kinks and decompression sickness as they slip past each other , which generates more flaw , " van der Elst said .
Plate boundaries where one tectonic plate dives beneath another are calledsubduction geographical zone . Subduction zone bring forth some of the most herculean quake on Earth . For instance , both the 2011Tohoku earthquakeand the 2004 Banda Aceh earthquake off Indonesia occurred due to snap at jab faults on subduction zones .
Related : The 20 big earthquakes in recorded story
single fault line are usually narrow than their length or depth . Most earthquakes strike less than 50 mi ( 80 klick ) below Earth ’s surface . The bass earthquake occur on inverse faults at about 375 international nautical mile ( 600 kilometre ) below the Earth’s surface . Below these depths , rock’n’roll are probably too warm for faulting to generate enough friction to create earthquakes , van der Elst said .
Earth’s biggest exposed fault
For about a century , scientist have been aware of a 4.47 mile - cryptic ( 7.2 kilometer ) oceanic abysm — cognize as the Weber Deep — locate off the glide of eastern Indonesia in the Banda Sea . But until of late , they had been ineffective to explain how it come so deep .
The Weber Deep is the deepest detail in the sea that is not in a trench ; trench are formed during the subduction of two tectonic plate — when one slides under the other . However , the Weber Deep is a forearc basin , which is essentially adepression settle in front of the Banda arc(curved chain of volcanic islands ) , according to New Atlas .
This Banda Detachment fault represents a rip in the sea floor that is exposed for more than 23,166 square miles ( 60,000 satisfying km ) . In fact , in some expanse , the amount of extension was so severe that there was no longer any suggestion of pelagic freshness , according to New Atlas .
