Compressive stress
happens at convergent plate boundaries where two plates move toward each other. Tensional stress happens at divergent plate boundaries where two plates are moving away from each other. Shear stress is experienced at transform boundaries where two plates are sliding past each other.
What stress is caused by two plates pushing into one another?
Shear Stress
: Stress which occurs when tectonic plates move past each other causing rock to twist or change shape.
What type of stress occurs when a rock mass is pushed in parallel and opposite directions compression faulting shearing tension?
Shear stress
happens when there is parallel movement of two rock masses, but in the opposite directions. They slide against each horizontally, resulting in stress and tear. The rock masses may also bend under such great pressure, creating folds.
What causes tectonic plates to move?
Earth’s crust, called the lithosphere, consists of 15 to 20 moving tectonic plates. …
The heat from radioactive processes within the planet’s interior
causes the plates to move, sometimes toward and sometimes away from each other. This movement is called plate motion, or tectonic shift.
At which type of boundary does tension occur?
Compression is the most common stress at convergent plate boundaries. Rocks that are pulled apart are under tension. Rocks under tension lengthen or break apart. Tension is the major type of stress at
divergent plate boundaries
.
What type of stress is placed on a normal fault?
Tensional stress
is when rock slabs are pulled apart from each other, causing normal faults. With normal faults, the hanging wall slips downward relative to the footwall. Compressional stress is when rock slabs are pushed into each other, like cars in a head-on collision.
What type of stress occurs when a rock is pushed in opposite directions?
Tension
is a directed (non-uniform) stress that pulls rock apart in opposite directions. The tensional (also called extensional) forces pull away from each other. Compression is a directed (non-uniform) stress that pushes rocks together.
Which type of stress is a uniform?
This uniform stress is called
lithostatic pressure
and it comes from the weight of rock above a given point in the earth. Lithostatic pressure is also called hydrostatic pressure.
What are three causes of plate movement?
Mantle dynamics, gravity, and Earth’s rotation taken
altogether causes the plate movements. However, convectional currents are the general thought for the motion.
How fast do tectonic plates move?
They can move at
rates of up to four inches (10 centimeters) per year
, but most move much slower than that. Different parts of a plate move at different speeds. The plates move in different directions, colliding, moving away from, and sliding past one another. Most plates are made of both oceanic and continental crust.
What happens when tectonic plates stopped moving?
If all plate motion stopped, Earth would be a very different place. …
Erosion
would continue to wear the mountains down, but with no tectonic activity to refresh them, over a few million years they would erode down to low rolling hills.
Which type of stress is most likely to occur at this boundary?
Rocks under tension lengthen or break apart. Tension is the major type of stress at divergent plate boundaries. When forces are parallel but moving in opposite directions, the stress is called shear.
Shear stress
is the most common stress at transform plate boundaries.
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.
What is a real example of tensional stress?
A prime example of tensional stress is
the mid-Atlantic ridge
, where the plates carrying North and South America are moving west, while the plates carrying Africa and Eurasia are moving east. Tensional stress can also occur well within an existing plate, if an existing plate begins to split itself into two pieces.
What type of stress causes dip-slip faults?
A strike-slip fault is a dip-slip fault where the dip of the fault plane is vertical. Strike-slip faults result from
shear stresses
. If you stand with one foot on each side of a strike-slip fault, one side will be moving toward you while the other side moves away from you.
What causes the fault to move?
A fault is formed in the Earth’s crust as a
brittle response to stress
. Generally, the movement of the tectonic plates provides the stress, and rocks at the surface break in response to this. … If you whack a hand-sample-sized piece of rock with a hammer, the cracks and breakages you make are faults.
