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.During an earthquake, the rock on one side of the fault suddenly slips with respect to the other.The fault surface can be horizontal or vertical or some arbitrary angle in between.
Earth scientists use the angle of the fault with respect to the surface (known as the dip) and the direction of slip along the fault to classify faults.Faults which move along the direction of the dip plane are dip-slip faults and described as either normal or reverse (thrust), depending on their motion.Faults which move horizontally are known as strike-slip faults and are classified as either right-lateral or left-lateral.Faults which show both dip-slip and strike-slip motion are known as oblique-slip faults.
The following definitions are adapted from The Earth by Press and Siever.
normal fault - a dip-slip fault in which the block above the fault has moved downward relative to the block below.This type of faulting occurs in response to extension and is often observed in the Western United States Basin and Range Province and along oceanic ridge systems.
Normal Fault Animation
reverse (thrust) fault - a dip-slip fault in which the upper block, above the fault plane, moves up and over the lower block.This type of faulting is common in areas of compression, such as regions where one plate is being subducted under another as in Japan.When the dip angle is shallow, a reverse fault is often described as a thrust fault.
Thrust Fault Animation
Blind Thrust Fault Animation
strike-slip fault - a fault on which the two blocks slide past one another.The San Andreas Fault is an example of a right lateral fault.
Strike-slip Fault Animation
A left-lateral strike-slip fault is one on which the displacement of the far block is to the left when viewed from either side.
A right-lateral strike-slip fault is one on which the displacement of the far block is to the right when viewed from either side.
FAQs
There are four types of faulting -- normal, reverse, strike-slip, and oblique. A normal fault is one in which the rocks above the fault plane, or hanging wall, move down relative to the rocks below the fault plane, or footwall. A reverse fault is one in which the hanging wall moves up relative to the footwall.
What is a fault in science? ›
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.
What are the 3 types of faults describe how each type of fault moves? ›
Normal faults occur when two plates, one on top of the other, slide past each other and create the fault. Reverse faults occur when one plate slides under the other, creating a vertical offset. Strike-slip faults happen when two plates move horizontally past each other.
What are the 3 types of faults and the types of stress associated with them? ›
In terms of faulting, compressive stress produces reverse faults, tensional stress produces normal faults, and shear stress produces transform faults.
What are the 3 types of fault? ›
There are three main types of fault which can cause earthquakes: normal, reverse (thrust) and strike-slip.
What are the 4 parts of a fault? ›
The main components of a fault are (1) the fault plane, (2) the fault trace, (3) the hanging wall, and (4) the footwall.
What is a fault easy definition? ›
noun. a defect or imperfection; flaw; failing: a fault in the brakes; a fault in one's character. Synonyms: shortcoming, frailty, blemish.
What is a fault simple definition? ›
fault, failing, frailty, foible, vice mean an imperfection or weakness of character. fault implies a failure, not necessarily culpable, to reach some standard of perfection in disposition, action, or habit.
What is fault with example? ›
A fault is a large crack in the surface of the earth. ... the San Andreas Fault. A fault in tennis is a service that is wrong according to the rules.
How do faults form? ›
It forms when rock above an inclined fracture plane moves downward, sliding along the rock on the other side of the fracture. Normal faults are often found along divergent plate boundaries, such as under the ocean where new crust is forming. Long, deep valleys can also be the result of normal faulting.
While California's 15,700 faults might sound like a lot, there are thousands upon thousands of different types of earthquake faults and different types of fault lines as part of the North American Plate and other plate boundaries around the world.
What are the parts of a fault? ›
The main components of a fault are (1) the fault plane, (2) the fault trace, (3) the hanging wall, and (4) the footwall. The fault plane is where the action is. It is a flat surface that may be vertical or sloping. The line it makes on the Earth's surface is the fault trace.
Where are the youngest rocks in a structural basin found? ›
Because the strata dip toward the center, the exposed strata in a basin are progressively younger from the outside in, with the youngest rocks in the center.
What is an example of a normal fault? ›
In a normal fault, 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. Other names: normal-slip fault, tensional fault or gravity fault. Examples: Sierra Nevada/Owens Valley; Basin & Range faults.
What are the different types of faults and plate boundaries? ›
Boundaries between tectonic plates are made up of a system of faults. Each type of boundary is associated with one of three basic types of fault, called normal, reverse and strike-slip faults. Plates can move apart at a boundary. This type of boundary is called a divergent boundary.
What is a fault in plate tectonics? ›
Faults are cracks in the earth's crust along which there is movement. These can be massive (the boundaries between the tectonic plates themselves) or very small.
What is a fault quizlet? ›
fault. A fault is a break in a rock in which movement has taken place. Normal Fault. When areas of the Earth are pulled apart (tension/tensile stress) a normal fault is formed.
What are the 3 main types of plate boundaries? ›
There are three kinds of plate tectonic boundaries: divergent, convergent, and transform plate boundaries. This image shows the three main types of plate boundaries: divergent, convergent, and transform. Image courtesy of the U.S. Geological Survey.
What is a fault plane in geology? ›
A fault plane is the plane that represents the fracture surface of a fault. A fault trace or fault line is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault.
