Fault

FaultSavaros Phanom-upatham No.5

Monchanok Sankaew No.6Sasivimon Rujirat No.10

Natatha Pienchobtham No.16

Fault A fault is a fracture or zone of fractures between two blocks of

rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the form of an earthquake -

or may occur slowly, in the form of creep. Faults may range in length from a few millimeters to thousands of

kilometers. Most faults produce repeated displacements over geologic time.

Caused Faults are cracks in rock caused by forces that compress or stretch

a section of Earth’s crust. Earth’s crust is divided up into several tectonic plates that

essentially float on a mantle of plastic, partially melted rocks. These plates slide under or slide past one another, stressing the

rock along the edges of each plate. A new fault forms when the stress on the rock is great enough to

cause a fracture, and one wall in the fracture moves relative to the other.

Faults can also appear far from the boundaries between tectonic plates when stress caused by rising magma from the mantle overcomes the strength of rocks in the overlying crust.

Caused  Many forces change the surface of the Earth over time. The largest force that changes our planet’s surface is movement of

Earth's outer layer in a process called plate tectonics.  The Earth’s outer layer, called the lithosphere, is broken into

plates which fit together like a jigsaw puzzle. These plates move very slowly (about 2 inches per year).  The Earth is constantly moving and plates were formed by the

breaking of the Earth's surface that slide over the mantel.  The plates that move apart are called Divergent fault boundaries

(mid Atlantic ridge) or seafloor spreading. This is mostly caused by convection in the Mantel. Plates that slide by each other are called transform fault

boundaries or "slip faulting"

4 Basic Classes Of Faults

Normal faults the block above the fault moves down relative to the block below

the fault. This fault motion is caused by tensional forces and results in

extension. 

Owens valley, California

Horst and Graben Topographic features found in a normal fault zone forming

ridges and valleys. A graben represents a block of land that has dropped down

relative to the landscape • Such as dead valley, Jordan-dead sea , and etc.

A horst represents a block of land remaining higher than the general landscape.• Such as  The Vosges Mountains of France, the Palestine Plateau, and etc.

Reverse fault The block above the fault moves up relative to the block below the

fault. Caused by compression forces and results in shortening. If the dip of the fault plane is small

• called a thrust fault 

Rocky Mountains, Himalayas

Strike-slip faults Strike-slip faults involve motion which is parallel to the strike of

the faul frequently described as a "side-by-side" motion. Strike-slip faults are further described as "right-lateral" (dextral) or

"left-lateral" (sinistral) depending if the block opposite the viewer moved to the right or left respectively.

Anatolian Fault, Turkey=right lateral fault

Transform Fault A transform fault is a type of strike-slip fault where in the relative

horizontal slip is accommodating the movement between two ocean ridges or other tectonic boundaries.

Only occur at the boundary between two plates

San Andreas Fault, California=right lateral fault

Oblique-slip Fault  Oblique-slip faulting is a combination of dip-slip fault and strike-

slip fault. Therefore, there is a space between the faces of the fault. One side is higher, vertically, than the other

Problems from faulting Escarpments and mountains hinder transport development. Rift valleys are very hot and only suitable for grazing

• they are in the rain shadow unless irrigation is practised as with the case of mubuku.

There is severe soil erosion and mass wasting on the step slopes which result in the destruction of soil surface, crops and at times people's property.

• For example Rwenzori mountains.

It is difficult to settle on the steep areas on the rift valley escarpments.

Problems faced by the people living

in the Rift valley areas of East Africa. High temperatures lead to shortage of water. Earthquakes (tremors) which destroy property  Little rainfall or drought in the Rain shadow areas  Poor means of transport and communication because of the steep

escarpments  Salty lakes because of high temperatures and high evaporation

rates Soil erosion and land slides especially on the steep slopes 

Reference https://answers.yahoo.com/question/index?qid=201007042157

18AAq5mMb http://scec.usc.edu/internships/useit/eqbasicinfo http://darkwing.uoregon.edu/~millerm/SSfaults.html http://www.iris.edu/hq/programs/education_and_outreach/anima

tions/2 http://eqseis.geosc.psu.edu/~

cammon/HTML/Classes/IntroQuakes/Notes/faults.html http://blogs.britannica.com/2011/02/how-fault-lines-form/ https://

answers.yahoo.com/question/index?qid=20080308174950AAolkZi

http://www.elateafrica.org/elate/geography/earthmovements/faultiing.html