Chapter 13

Question 1

elastic rebound theory

Answer 1

as the crustal blocks on either side of a fault are deformed by tectonic forces, they remain locked in place by friction until they fracture and rebound to an undeformed state

Question 2

fault slip

Answer 2

the distance of displacement

Question 3

recurrence interval

Answer 3

the time between ruptures of the buildup and release of elastic energy

Question 4

focus

Answer 4

the point at which the fault slipping begins

Question 5

epicenter

Answer 5

the point on the surface of the Earth directly above the focus

Question 6

afterchocks

Answer 6

smaller earthquakes after the mainshock

Question 7

foreshock

Answer 7

small earthquake before the mainshock

Question 8

seismograph

Answer 8

an instrument that records seismic waves

Question 9

types of seismic waves

Answer 9

p waves
s waves
surface waves

Question 10

p waves

Answer 10

primary waves

Question 11

s waves

Answer 11

secondary waves

Question 12

surface waves

Answer 12

slower waves that travel around the Earth’s surface

Question 13

what type of wave is a p wave?

Answer 13

compressional wave - push-pull wave

Question 14

what can p waves travel through?

Answer 14

solids, liquids or gaseous materials

Question 15

what type of wave is an s wave

Answer 15

shear waves - displace material at right angle to their path

Question 16

what can s waves travel through and how fast?

Answer 16

solids only

a little more than half the speed of p waves

Question 17

fault mechanism

Answer 17

the orientation of the fault rupture anf the direction of slipping

Question 18

Mercalli intensity scale

Answer 18

assigns a roman numeral (I - XII) to the intensity of the earthquake

Question 19

what type of faulting occurs at divergent boundaries?

Answer 19

normal faulting

Question 20

how deep are earthquakes at divergent boundaries?

Answer 20

shallow

Question 21

what type of faulting occurs at transform-fault boundaries?

Answer 21

strike-slip faulting

Question 22

at what plate boundary do the largest earthquakes occur?

Answer 22

convergent boundaries

Question 23

how deep are the earthquakes at convergent boundaries?

Answer 23

the deepest earthquakes occur at convergent boundaries

Question 24

how deep are intraplate earthquakes?

Answer 24

relatively shallow

Question 25

what type of earthquakes cause tsunamis?

Answer 25

megathrust events (compressional)