Fault (geology)
In geology, a fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement along the fractures as a result of earth movement. Large faults within the Earth's crust result from the action of plate tectonic forces. Energy release associated with rapid movement on active faults is the cause of most earthquakes, such as occurs on the San Andreas Fault, California.
A fault line is the surface trace of a fault, the line of intersection between the fault plane and the Earth's surface.
Since faults do not usually consist of a single, clean fracture, geologists use the term fault zone when referring to the zone of complex deformation associated with the fault plane.
The two sides of a non-vertical fault are known as the hanging wall and footwall. By definition, the hanging wall occurs above the fault plane and the footwall occurs below the fault. This terminology comes from mining: when working a tabular ore body, the miner stood with the footwall under his feet and with the hanging wall hanging above him.
Read more about Fault (geology): Mechanics, Slip, Heave, Throw, Fault Types, Fault Rock, Impacts On Structures and People
Famous quotes containing the word fault:
“I often accuse my finest acquaintances of an immense frivolity; for, while there are manners and compliments we do not meet, we do not teach one another the lessons of honesty and sincerity that the brutes do, or of steadiness and solidity that the rocks do. The fault is commonly mutual; however, for we do not habitually demand any more of each other.”
—Henry David Thoreau (1817–1862)