Rock may bend or break when different amounts of stress are applied. The process by which the shape of a rock changes in response to stress is called deformation. The bending of rock layers in response to stress is called
folding
.
What are the 3 fault types?
There are three main types of fault which can cause earthquakes:
normal, reverse (thrust) and strike-slip
. Figure 1 shows the types of faults that can cause earthquakes. Figures 2 and 3 show the location of large earthquakes over the past few decades.
What stress causes rocks to fold?
Compression
squeezes rocks together, causing rocks to fold or fracture (break) (figure 1). Compression is the most common stress at convergent plate boundaries.
Is a bending of rocks without breaking?
In response to stress, rocks will undergo some form of bending or breaking, or both. The bending or breaking of rock is called deformation or strain. … If rocks tend to bend without breaking, they are said to be
ductile
.
What caused the layers to bend?
Deformation structures, such as faults and folds, form as a result of stress in the lithosphere. This stress is caused by tectonic plate motion. Folding occurs when rock layers bend
because of stress
. Faulting occurs when rock layers break because of stress and then move on either side of the break.
What are the 3 types of stress in rock?
Stress is a force acting on a rock per unit area. It has the same units as pressure, but also has a direction (i.e., it is a vector, just like a force). There are three types of stress:
compression, tension, and shear
.
What does shear stress do to rocks?
Shearing in rocks. The white quartz vein has been elongated by shear. When
stress causes a material to change shape, it has undergone strain or deformation
. Deformed rocks are common in geologically active areas.
What happens when too much stress is applied to a rock?
If more stress is applied to the rock,
it bends and flows
. It does not return to its original shape. Near the surface, if the stress continues, the rock will fracture (rupture) and break.
What are the 4 major types of faults?
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 tensional stress?
Tensional stress is
the stress that tends to pull something apart
. It is the stress component perpendicular to a given surface, such as a fault plane, that results from forces applied perpendicular to the surface or from remote forces transmitted through the surrounding rock.
Which is an example of reverse fault?
Reverse faults are dip-slip faults in which the hanging wall moves up relative to the footwall. Reverse faults are the result of compression (forces that push rocks together).
The Sierra Madre fault zone of southern California
is an example of reverse-fault movement.
What happens when rocks become deformed?
When rocks deform in a ductile manner, instead of fracturing to form faults or joints,
they may bend or fold
, and the resulting structures are called folds. Folds result from compressional stresses or shear stresses acting over considerable time.
Which type of strain can cause a rock to bend without breaking?
Ductile materials respond to stress by bending or deforming without breaking.
Ductile strain
is a change in the volume or shape of rock in which the rock does not crack or fracture.
What will happen when rocks did not fold?
What happens when rocks don’t fold?
rock will not fold but will break like any other brittle solid
. The line of the break is called a fault. The pressure is still on the two sides of the fault so the bits of rock usually start sliding slowly past each other.
Which type of stress is a uniform?
There are four general types of stress.
One type of stress is uniform
, which means the force applies equally on all sides of a body of rock. The other three types of stress, tension, compression and shear, are non-uniform, or directed, stresses. All rocks in the earth experience a uniform stress at all times.
What causes compressional stress?
It is the stress component perpendicular to a given surface, such as a fault plane, that results from
forces applied perpendicular to the surface
or from remote forces transmitted through the surrounding rock.
