The document discusses different types of faults including normal faults, thrust faults, strike-slip faults, transform faults, and oblique-slip faults. It provides examples of each type of fault and explains the forces and motions that cause each one. Faults form when stress in the earth's crust exceeds the strength of rocks, causing fractures. The movement of tectonic plates applies stress that can result in earthquakes at fault boundaries.
2. 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.
3. 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.
4. 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"
5.
6. 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
7. 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.
8. 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
9. 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
10. 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
11. 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
12. 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.
13. 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