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a force that acts on rock to change its shape or volume


Stress that stretches rock so that it becomes thinner in the middle.


stress that squeezes rock until it folds or breaks


stress that pushes masses of rock in opposite directions, in a sideways movement

Normal fault

an inclined fault in which the hanging wall appears to have slipped downward relative to the footwall

Hanging wall

The block of rock that forms the upper half of the fault


the lower wall of an inclined fault

Reverse fault

a type of fault where the hanging wall slides upward; caused by compression in the crust

Strike-slip fault

break in rock caused by shear forces, where rocks move past each other without much vertical movement


a fold in rock that bends upward into an arch


A downward fold in rock formed by compression in Earth's crust.


an area of high, flat land


shaking and vibration at the surface of the earth resulting from underground movement along a fault plane of from volcanic activity


The area beneath the Earth's surface where the rock is under stress


point on Earth's surface directly above an earthquake's focus

P wave

a seismic wave that causes particles of rock to move in a back-and-forth direction

S wave

a type of seismic wave that moves the ground up and down or side to side

Surface waves

seismic waves that travel along the Earth's surface

Mercalli scale

a scale of earthquake intensity


Is the number geologists assign based on the earthquake's size

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