Earthquake deck (Exam 2)

Question 1

What is an earthquake?

Answer 1

shaking caused by the breaking or frictional sliding of rock in the Earth

Question 2

What are faults?

Answer 2

planar breaks in rock along which appreciable movement has occurred

Question 3

What are dip-slip faults?

Answer 3

vertical component of displacement

Question 4

Types of dip-slip?

Answer 4

Normal fault, reverse fault, thrust fault

Question 5

Define normal fault:

Answer 5

the hanging wall moves down relative to the footwall

Question 6

Define reverse fault:

Answer 6

the hanging wall moves up relative to the footwall

Question 7

Define thrust fault:

Answer 7

a low angle (<30 deg) reverse fault

Question 8

What are strike slip faults?

Answer 8

horizontal component of displacement

Question 9

Type of strike slip faults:

Answer 9

left lateral, right lateral

Question 10

Define stress in earthquakes:

Answer 10

the force applied to an object; stress along faults usually is due to tectonic activity

Question 11

Types of stress:

Answer 11

compressive, tensile, shear stress

Question 12

What is compressive stress?

Answer 12

form thrust and reverse faults

Question 13

What is tensile stress?

Answer 13

form normal faults

Question 14

What is shear stress?

Answer 14

form strike-slip faults

Question 15

What is a strain?

Answer 15

deformation (change in shape) resulting from stress

Question 16

What are strike slip motions?

Answer 16

Alternation between stress buildup and earthquake-generating slip
Strike: friction prevents motion
Slip: friction is briefly overwhelmed by motion

Question 17

Define hypocenters:

Answer 17

where the slip/rupture occurs on the fault

Question 18

Define epicenter:

Answer 18

land surface directly above the hypocenter

Question 19

Define seismic waves:

Answer 19

energetic waves released from earthquake

Question 20

Types of body waves:

Answer 20

p-wave, s-wave

Question 21

Define p-wave:

Answer 21

Primary, fastest, compressional waves

Question 22

Define s-wave:

Answer 22

Secondary, shear waves

Question 23

other types of waves are?

Answer 23

L-waves, R-waves

Question 24

Define L-waves:

Answer 24

Love waves, horizontal shear, shaking side to side

Question 25

Define R-waves:

Answer 25

Raleigh waves, ground roll, cause ground to undulate up and down

Question 26

To find an epicenter you need:

Answer 26

1. Need 3 seismic stations 2. Measure the difference between P and S-wave arrival times

Question 27

Define magnitude:

Answer 27

quantitative, measure the amount of ground motion and energy released during an earthquake

Question 28

Measures of magnitude:

Answer 28

1. Richter scale - useful near the epicenter 2. Moment magnitude scale - most accurate measure (looks at strength of rock and amount of slip

Question 29

Intensity refers to?

Answer 29

qualitative, effects that an earthquake has on humans and surface features

Question 30

Where do earthquakes occur?

Answer 30

1. Divergent Plate Boundary 2. Transform Plate Boundary 3. Convergent Plate Boundary

Question 31

Define divergent PB:

Answer 31

develop normal and strike-slip faults, shallow earthquakes

Question 32

Define transform PB:

Answer 32

develop strike-slip faults, shallow earthquakes

Question 33

Define convergent PB:

Answer 33

develop reverse faults, earthquakes can be shallow to deep