Earth and Space Module 15

What do rocks undergo when stress builds up past the elastic limit?

plastic deformation

Which type of fault occurs when rocks on one side of a fault move up relative to the other side?

reverse

secondary wave

Causes rock to move at right angles to the direction in which the wave travels

sureface wave

Causes rock to move both up and down and from side to side

fault plane

Fault surface along which movement takes place

fault

Fracture along which movement occurs

strike-slip fault

Fracture caused by horizontal shear

normal fault

Fracture caused by horizontal tension

reverse fault

Fracture that forms as a result of horizontal compression

What happens to a rock that undergoes elastic deformation once the stress is removed?

It returns to its original shape.

primary wave

Squeezes and pulls rock in the same direction as the wave travels

Magnitude is measured on the Richter scale using differences in

amplitude of seismic waves.

decreases the volume of a material

compression

S-waves do not enter the core because they cannot travel through solids.

false

Studies of how waves reflect deep inside Earth show that Earth's inner core is solid.

false

What is a measure of the energy released during an earthquake?

intensity

What is strain?

measure of the deformation of rocks

Which scale rates the types of damage and other effects of an earthquake as noted by observers during and after its occurrence?

modified Mercalli scale

Which scale uses Roman numerals to designate the degree of earthquake intensity?

modified Mercalli scale

What is the rating scale that measures the energy released by an earthquake, taking into account the size of the fault rupture, the amount of movement along the fault, and the rocks' stiffness?

moment magnitude scale

Which type of fault occurs when rocks on one side of a fault move down relative to the other side?

normal

What numerical rating system measures the energy of the largest seismic wave?

richter scale

What is the record produced by a seismometer?

seismogram

causes a material to twist

shear

pulls a material apart

tension

Seismologists have reasoned that Earth's outer core must be liquid based on the disappearance of S-waves.

true

What is stress

force per unit area

Surface waves are the first to arrive at a seismic station.

False

San andreas

Famous California strike-slip fault

What is the total force acting on crustal rocks per unit of area?

stress