There are three main types of fault that may cause an earthquake

What Is a Geologic Fault?A fault is a crack in the Earth's crust. Typically, faults are associated with, or form, the boundaries between Earth's tectonic plates. In an active fault, the pieces of the Earth's crust along a fault move over time. The moving rocks can cause earthquakes. Inactive faults had movement along them at one time, but no longer move. The type of motion along a fault depends on the type of fault. The main types of faults are described below:

Normal dip-slip fault o Normal faults happen in areas where the rocks are

pulling apart (tensile forces) so that the rocky crust of an area is able to take up more space.

o The rock on one side of the fault is moved down relative to the rock on the other side of the fault.

o Normal faults will not make an overhanging rock ledge.

o In a normal fault it is likely that you could walk on an exposed area of the fault.

Reverse dip-slip fault o Reverse faults happen in areas where the rocks are

pushed together (compression forces) so that the rocky crust of an area must take up less space.

o The rock on one side of the fault is pushed up relative to rock on the other side.

o In a reverse fault the exposed area of the fault is often an overhang. Thus you could not walk on it.

o Thrust faults are a special type of reverse fault. They happen when the fault angle is very low.

Transform (strike-slip) faults o The movement along a strike slip fault is horizontal

with the block of rock on one side of the fault moving in one direction and the block of rock along the other side of the fault moving in the other direction.

o Strike slip faults do not make cliffs or fault scarps because the blocks of rock are not moving up or down relative to each other.

However, faults are usually more complex than these diagrams suggest. Often movement along a fault is not entirely of one variety. A fault may be some combination of strike slip and normal or reverse faulting. To further complicate these conditions, faults are often not just one orderly break in the rock, but are instead a number of fractures caused by similar motions of the Earth's crust. These clusters of faults are called fault zones.Some famous geological faults are:

1. The San Andreas Fault –USA.2. North Anatolian Fault-Turkey.3. Liquine-Ofqui Fault-Chile.4. Macquarie Fault Zone-Pacific Ocean from New Zealand to Indonesia.5. Chaman Fault-Pakistan and Afghanistan.

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The San Andreas Fault

Map of the San Andreas Fault (Red Line) By David K. Lynch, Ph.DThe San Andreas Fault is the sliding boundary between the Pacific Plate and the North American Plate. It slices California in two from Cape Mendocino to the Mexican border. San Diego, Los Angeles and Big Sur are on the Pacific Plate. San Francisco, Sacramento and the Sierra Nevada are on the North American Plate. And despite San Francisco’s legendary 1906 earthquake, the San Andreas Fault does not go through the city. But communities like Desert Hot Springs, San Bernardino, Wrightwood, Palmdale, Gorman, Frazier Park, Daly City. Point Reyes Station and Bodega Bay lie squarely on the fault and are sitting ducks.

The San Andreas Fault is a transform fault. Imagine placing two slices of pizza on the table and sliding them past one another where they touch along a common straight edge. Bits of pepperoni from one side crumble across the boundary onto the anchovy side. The same thing happens with the fault, and the geology and landforms along the mighty rift are extremely complicated.

The plates are slowly moving past one another at a couple of inches a year - about the same rate that your fingernails grow. But this is not a steady motion, it is the average motion. For years the plates will be

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locked with no movement at all as they push against one another. Suddenly the built-up strain breaks the rock along the fault and the plates slip a few feet all at once. The breaking rock sends out waves in all directions and it is the waves that we feel as earthquakes.

In many places like the Carrizo Plain (San Luis Obispo County) and the Olema Trough (Marin County), the fault is easy to see as a series of scarps and pressure ridges. In other places, it is more subtle because the fault hasn’t moved in many years and is covered with alluvium, or overgrown with brush. In San Bernardino and Los Angeles Counties, many of the roads along the fault cut through great mountains of gouge, the powdery, crumbled rock that has been pulverized by the moving plates.

The hallmark of the San Andreas Fault is the different rocks on either side of it. Being about 28 million years old, rock from great distances have been juxtaposed against rocks from very different locations and origins. The Salinian block of granite in central and northern California originated in Southern California, and some even say northern Mexico. Pinnacles National Monument in Monterey County is only half of a volcanic complex, the other part being 200 miles southeast in Los Angeles County and is known as the Neenach Volcanics.

There are many myths and legends about the San Andreas Fault, the biggest being that it will one day crack and California will slide into the sea. WRONG! It won’t happen and it can’t happen. Nor is there any thing such as “earthquake weather” or preferred times of day when earthquakes hit. The San Andreas Fault is more accessible than any other fault in the world. With California’s large population and temperate climate, there are many roads that snake along the fault. They are uncrowded and peaceful, perfect for family outings. There is abundant camping, bird watching, wild flowers and wildlife, rock collecting and natural beauty along the way. State and National parks are strung along the fault like beads on a string. All it takes is a good map, a comfortable car and a desire to see the world’s most famous fault.

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The San Andreas Fault

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About the Author

David K. Lynch, PhD, is an astronomer and planetary scientist living in Topanga, CA. When not hanging around the fault or using the large telescopes on Mauna Kea, he plays fiddle, collects rattlesnakes, gives public lectures on rainbows and writes books (Color and Light in Nature, Cambridge University Press) and essays. Dr. Lynch's latest book is the Field Guide to the San Andreas Fault. The book contains twelve one-day driving trips along different parts of the fault, and includes mile-by-mile road logs and GPS coordinates for hundreds of fault features. As it happens, Dave's house was destroyed in 1994 by the magnitude 6.7 Northridge earthquake.

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Map of the San Andreas Fault (Red Line) - copyright by David Lynch (click to enlarge).

Aerial photo of the San Andreas Fault showing drainage that is offset by movement of the fault. Photograph copyright by David Lynch. Click image to enlarge.

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I will give you ten, since you have not designated an area, these will be listed in random order and occur variously on the Globe. I have however listed the country that may be most affected by seismic activity. Remember this type of natural occurrence is not governed by the boundaries we use to indicate territorial boundaries.

North Anatolian Fault-Turkey.

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Liquine-Ofqui Fault-Chile.

Macquarie Fault Zone-Pacific Ocean from New Zealand to Indonesia.

Chaman Fault-Pakistan and Afghanistan.

San Jacinto Fault Zone-United States West Coast (California)-It is considered to be the most seismically active fault zone in Southern California, contrary to popular beliefs that the infamous San Andreas Fault is the most active.

Chixoy-Polochic Fault-Central America, widely feared in Guatemala.

Itoigawa-Shizuoka-Japan.

East Anatolian Fault-Turkey again, see above.

Motagua Fault-Central America and Guatemala again.

Calaveras Fault-United States West Coast-California, again.

A search using "longest fault line in the world" yield information that suggests:1.The longest fault might be the one that ruptured causing the Sumatra-Andaman earthquake (holds record for longest rupture @ 720 to 780 miles).2. This puts the San Andreas in at least 2nd place at ~625 miles.There is also a fault that the St. Lawrence River follows but information about it's total length is sketchy. If the river follows a fault along its entire length that could be the longest at 2,350 miles.3. Massive earthquakes have happened in Chile, so there could be long ones in that part of the world.4. The North Anatolian fault in Turkey has also been described as one of the world's longest.

If you go to the USGS Earthquake site (last link below), you could get maps of various regions of the world and trace the fault lines to make a list of your own.

Source(s):

http://www.sciencedaily.com/releases/200…http://www.rev.net/~aloe/river/http://earthquake.usgs.gov/research/geol…http://earthquake.usgs.gov/earthquakes/r…

Liquiñe-Ofqui FaultFrom Wikipedia, the free encyclopediaJump to: navigation, search

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The Liquiñe-Ofqui Fault marked with red.

The Liquiñe-Ofqui Fault is major geological fault [1] that runs a length of roughly 1000 km in a north-south direction and exhibits current seismicity [2]. It is located in the Chilean northern patagonean Andes. It is a dextral intra-arc transform fault. When considered a fault zone, the Liquiñe-Ofqui Fault Zone (LOFZ) migh include other neigboring faults such as Reigolil-Pirihueico Fault.

As the name implies it runs from the Liquiñe hot springs in the north to the Ofqui Isthmus in the south, where the Antarctic Plate meets the Nazca Plate and the South American Plate in Chile Triple Junction. A large part of the fault runs along the Moraleda Channel. North of Liquiñe the fault is gradually converted into a compression area. At Quetrupillán volcano the fault is crossed by the Gastre Fault Zone. It may be classified as a dextral intra-arc transform fault.

The 1960 eruption of Cordón Caulle soon after the Great Chilean Earthquake was triggered by movements in the fault. The Aysén Fjord earthquake in 2007 and the eruption of Chaitén Volcano in 2008 are believed to have been caused by movements in the fault.

[edit] References1. ̂ ""Revista geológica de Chile"". CRED. http://www.scielo.cl. Retrieved 1999-07-01. 2. ̂ Lange, D.; Cembrano, J.; Rietbrock, A.; Haberland, C.; Dahm, T. and Bataille, K (April 2008). "First seismic record

for intra-arc strike-slip tectonics along the Liquiñe-Ofqui fault zone at the obliquely convergent plate margin of the southern Andes,". Tectonophysics (Tectonophysics) 455 (1-4): 14. doi:10.1016/j.tecto.2008.04.014.

This tectonics article is a stub. You can help Wikipedia by expanding it.

This Chile location article is a stub. You can help Wikipedia by expanding it.

Chaman FaultFrom Wikipedia, the free encyclopediaJump to: navigation, search

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The Chaman Fault is a major, active geological fault in Pakistan and Afghanistan that runs for over 850 km.[1] Tectonically, it is actually a system of related geologic faults that separates the Eurasian Plate from the Indo-Australian Plate. It is a terrestrial, primarily transform, left-lateral strike-slip fault. The slippage rate along the Chaman fault system as the Indo-Australian Plate moves northward (relative to the Eurasian Plate) has been estimated at 10 mm/yr or more.[1] In addition to its primary transform aspect, the Chaman fault system has a compressional component as the Indian Plate is colliding with the Eurasian Plate. This type of plate boundary is sometimes called a transpressional boundary.[2]

From the south, the Chaman fault starts at the triple junction where the Arabian Plate, the Eurasian Plate and the Indo-Australian Plate meet, which is just off the Makran Coast of Pakistan. The fault tracks northeast across Balochistan and then north-northeast into Afghanistan, runs just to the west of Kabul, and then northeastward across the right-lateral-slip Herat fault, up to where it merges with the Pamir fault system north of the 38º parallel.[3]

The Ghazaband and Ornach-Nal faults are often included as part of the Chaman fault system. South of the triple junction, where the fault zone lies undersea and extends southwest to approximately 10ºN 57ºE, it is known as the Owen Fracture Zone.

While there is general agreement that the fault is slipping at a rate of at least 10 mm/yr, there is a report of volcanic rocks in Pakistan dated to 2 m.y. BP which have been offset such as to indicate a slip rate of 25–35 mm/yr.[4] Offsets have been described throughout the fault in Pakistan that are young enough that “only the alluvium of the bottom of active dry washes is not displaced.”[5]

The parallel mountain ranges of eastern Balochistan, (east to west) the Kirthar Mountains, the Khude Mountains, the Zarro Mountains, the Pab Mountains and the Mor Mountains, are a result of the compressional plate boundary and are aligned parallel to the Chaman fault movement. The fault itself is west of these ranges.

Chaman Fault ZoneThe Chaman fault zone is part of the Eurasian-Indian plate boundary complex, with the Suleiman Ranges marking a jog to the east in the northern edge of the Indian continental plate. The Chaman zone has evolved from a thrust fault of the Arabian-Eurasian collisional complex to a strike-slip fault along the Eurasian-Indian transform boundary.The Arabian-Eurasian plate boundary, a subduction zone, is beneath the Indian Ocean to the south of the Makran region. Sedimentary rocks (turbidites) that were originally deposited on the seafloor have been scraped off as the Arabian plate is subducted beneath the Eurasian plate. They were then uplifted and folded into the Makran Ranges during that plate collision. As India moves northward, the east ends of the Makran folds (on the Eurasian plate) have been dragged to the north along the Chaman fault zone.

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 STS061-80-10

Structures at the junction of the Arabian, Eurasian, and Indian plates are visible in this northward view across the Indian Ocean into Iran, Pakistan, and Afganistan. The Makran ranges (M) result from collision of the Arabian and Eurasian plates; that plate boundary is beneath the sea. The Chaman fault zone (C) and Suleiman folded ranges (S) reflect Indian and Eurasian plate interaction.The flat basin of the Helmand block (H) occupies the upper center of the frame. The three prominent volcanoes (V) are discussed in the context of the volcano line.In the next two frames, structural details of the sweeping bend in the Makran ranges and the evolution of the Chaman fault zone are highlighted.

 STS051J-43-S

 STS051J-43-P

Chaman fault is a thrust fault at T in this view, along which layers of rock have been driven up

In this view (a NE-ward continuation of STS051J-43-S), the Chaman (C) fault is

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and over those farther south.To the northeas it bends northward and becomes the strike-slip (S) fault of the transform zone - the block on the east is moving north (upward) relative to that on the west. 'Bending' of the beds south of Chaman fault is accomplished through small lateral displacements on a suite of closely spaced strike-slip faults -- much as each playing card in a deck slips a small distance past the next when the deck is flexed.

dominantly a strike-slip zone that defines the Eurasian-Indian transform plate boundary for ~900 km northward almost to Kabul, Afghanistan. The Indian plate (IP) is moving north (upper right) relative to the Eurasian plate (EA); disrupted drainages across the fault indicate ongoing motion. The earlier, original plate boundary lies in the broad valley at lower right. Dark clots within the belt are remnants of oceanic basaltic crust mixed with sedimentary rock (O - ophiolite).

References

1. ^ a b "USGS Unveils How Earthquakes Pose Risks to Afghanistan" News Release, 30 May 2007, United States Geological Survey

2. ̂ "Earthquakes Pose a Serious Hazard in Afghanistan" Fact Sheet 2007-3027, April 2007, United States Geological Survey

3. ̂ Fig.2 Chaman fault System associated with Indian Plate Boundary (April 2008) "Chaman Fault System (CFS) – a Prominent Seismo-tectonic Feature In Pakistan" Cowasjee Earthquake Study Centre Ned Newsletter 8(1): pp. 2-3, p.2

4. ̂ not viewed, cited by Lawrence , R. D.; Khan, S. Hasan and Nakata, T. (1992) "Chaman fault, Pakistan-Afghanistan" In Bucknam, R. C. and Hancock, P. L. (eds.) (1992) Major active faults of the world—Results of IGCP project 206 Annales Tectonicae 6(supplement): pp. 196–223

5. ̂ Lawrence, R. D.; Khan, S. Hasan and Nakata, T. (1992) "Chaman fault, Pakistan-Afghanistan" In Bucknam, R. C. and Hancock, P. L. (eds.) (1992) Major active faults of the world—Results of IGCP project 206 Annales Tectonicae 6(supplement): pp. 196–223, p. 204

North Anatolian FaultFrom Wikipedia, the free encyclopediaJump to: navigation, search

The North Anatolian Fault, and slip magnitudes along it of earthquakes in the 20th century

The North Anatolian Fault (NAF) (Turkish: Kuzey Anadolu Fay Hattı) is a major active right lateral-moving strike-slip fault in northern Anatolia which runs along the transform boundary between the Eurasian Plate and the Anatolian Plate. The fault extends westward from a junction with the East Anatolian Fault at the Karliova Triple Junction in eastern Turkey, across northern Turkey and into the Aegean Sea. It runs about 20 km south of Istanbul.

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[edit] Significant earthquakes along the fault

The North Anatolian and neighbouring faults cover most of Turkey

Since the disastrous 1939 Erzincan earthquake, there have been seven earthquakes measuring over 7.0 on the Richter scale, each has happened at a point progressively further west. Seismologists studying this pattern, believe that earthquakes happen in "storms" over a number of decades and that one earthquake triggers the next. By analysing the stresses caused along the fault by each earthquake, they were able to forecast a disturbance that hit the town of İzmit with such devastating effect in August 1999. It is thought that the chain is not complete, and that an earthquake will soon strike further west along the fault - perhaps in the heavily populated city of Istanbul.

Event Moment magnitude Casualties

1939 Erzincan 7.9 32,962 dead

1942 Niksar-Erbaa 6.9

1943 Tosya-Ladik 7.7

1944 Bolu-Gerede 7.5

1949 Karlıova 7.1

1951 Kurşunlu 6.9 50 dead, 3,354 injured

1957 Abant 6.8

1966 Varto 6.9 2,394 dead, 1,489 injured

1967 Mudurnu Valley 7.1 86 dead, 332 injured

1971 Bingöl 6.8

1992 Erzincan 6.5

1999 İzmit 7.4 17,480 dead and 23,781 injured

1999 Düzce 7.2 894 dead

[edit] See also San Andreas Fault List of earthquakes in Turkey

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[edit] External links Latest Seismicity In Turkey

Retrieved from "http://en.wikipedia.org/wiki/North_Anatolian_Fault"

Macquarie Fault ZoneFrom Wikipedia, the free encyclopediaJump to: navigation, search

The 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 to the Macquarie Triple Junction. It is also the tectonic plate boundary between the Indo-Australian Plate to the northwest and the Pacific Plate to the southeast.

The Macquarie Fault Zone includes a component of convergence which increases as it approaches the South Island of New Zealand. Many researchers conclude that the fault zone here is an incipient subduction zone, with oblique motion corresponding to the transition from lateral (strike-slip) motion. In the area known as the Puysegur Trench, the Indo-Australian Plate appears to be starting to sink beneath the Pacific Plate, the reverse of what is occurring off of New Zealand's North Island (see Kermadec-Tonga Subduction Zone).

A major geographic feature which runs along the Macquarie Fault Zone is known as the Macquarie Ridge. This ridge represents both the different relative heights of the abutting plates as well as the component of compression between the plates. The namesake Macquarie Island lies atop a segment of the Macquarie Ridge.

The Macquarie Fault Zone merges into the Alpine Fault which cuts across the continental crust of New Zealand's South Island.

A major 7.1 earthquake struck along this fault zone near Macquarie Island on April 12, 2008. [1]

[edit] References1. ̂ USGS Report

Transform and Subduction Tectonics Along the Macquarie Ridge, University of Texas

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