earthquakes

Question 1

travel-time graph

Answer 1

A graph of arrival times, commonly P or S waves, recorded at different points due to their distance from the focus of an earthquake. Used to find epicenter and determine when an earthquake occurred

Question 2

stress

Answer 2

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

Question 3

elastic deformation

Answer 3

Caused when a material is compressed, bent, or stretched but will return to to its original shape

Question 4

plastic deformation

Answer 4

permanent change in shape by bending and folding

Question 5

fault

Answer 5

a crack in the earth’s crust

Question 6

strike-slip fault

Answer 6

a type of fault where rocks on either side move past each other sideways with little up or down motion

Question 7

Secondary Waves (S Waves)

Answer 7

type of seismic body waves that are slower and only travel through solids, move up and down

Question 8

Primary Waves (P-Waves)

Answer 8

travel the fastest through rock material by causing particles in the rock to move back and forth, or vibrate, in the same direction as the waves are moving, also called compression wave

Question 9

surface waves (L-waves)

Answer 9

seismic waves that ripple along Earth’s surface. Slowest moving, cause the most damage. They roll like ocean waves

Question 10

triangulation of epicenter

Answer 10

the use of data from 3 seismic recording stations to locate the epicenter of an earthquake

Question 11

moment magnitude scale

Answer 11

A scale that rates earthquakes by estimating the total energy released by an earthquake

Question 12

tsunami

Answer 12

A giant wave usually caused by an earthquake beneath the ocean floor.

Question 13

strain

Answer 13

deformation of rocks in response to stress

Question 14

elastic limit

Answer 14

Maximum stress that a rock will withstand without permanent deformation

Question 15

compression

Answer 15

Stress that squeezes rock until it folds or breaks

Question 16

tension

Answer 16

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

Question 17

Shearing

Answer 17

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

Question 18

normal fault

Answer 18

break in rock caused by tension forces, where rock above the fault surface moves down relative to the rock below the fault surface

Question 19

reverse fault

Answer 19

a type of fault where the rock above the fault slides upward; caused by compression in the crust

Question 20

seismic waves

Answer 20

vibrations that travel through Earth carrying the energy released during an earthquake

Question 21

Seismometer

Answer 21

Instrument used to measure horizontal or vertical motion during an earthquake.

Question 22

Seismogram

Answer 22

the record of an earthquake’s seismic waves produced by a seismometer

Question 23

Richter scale

Answer 23

A scale that rates an earthquake’s magnitude based on the size of its seismic waves.

Question 24

Modified Mercalli Scale

Answer 24

a scale that rates the amount of shaking from an earthquake