Geo Unit 4

Question 1

Name the four fault classifications:

Answer 1

active, potentially active, inactive, and extinction

Question 2

What are the transmission of energies?

Answer 2

seismic waves

Question 3

What is the point at the surface above the focus?

Answer 3

epicenter

Question 4

What is the point in the crust where movement originates?

Answer 4

Hypocenter/ focus

Question 5

What are P waves?

Answer 5

primary waves (compression)

Question 6

P waves: How fast? What movement?

Answer 6

4mi/sec; jolts

Question 7

What are S waves?

Answer 7

Secondary waves (shear)

Question 8

S waves: How fast? What movement?

Answer 8

2mi/sec; up and down

Question 9

What are surface waves?

Answer 9

moves outward from the epicenter

Question 10

Surface waves: How fast? What movement?

Answer 10

1.5mi/sec; rolling zig-zag motion

Question 11

What is the written wave recording?

Answer 11

Seismogram

Question 12

What is the instrument that senses and records seismic waves?

Answer 12

Seismographs

Question 13

Name the three earthquake magnitude scales:

Answer 13

Mercalli, Richter, and Moment-Magnitue

Question 14

Which scale is measured by subjective descriptions?

Answer 14

Mercalli

Question 15

Which scale is measured by the energy release?

Answer 15

Richter

Question 16

Which scale is measured by seismic moment?

Answer 16

Moment-Magnitude

Question 17

How is the Moment-Magnitude scale calculated?

Answer 17

Length X depth X amount of slip X strength of rock

Question 18

What is liquefaction?

Answer 18

water saturated sediment

Question 19

What is one location that is a good example of liquefaction?

Answer 19

Port Royal, Jamaica: Disappearing Act (1692)
OR
Imperial Hotel, Tokyo (1915)

Question 20

What is the instantaneous displacement of the seafloor?

Answer 20

tsunami

Question 21

Tsunami speed _________ with shallow inland depth

Answer 21

Decreases

Question 22

What percent chance is there of a mega-quake in the next 50yrs?

Answer 22

40%

Question 23

What causes dilatency?

Answer 23

stress and bedrock expansion

Question 24

What is the result of dilatency?

Answer 24

microquakes and foreshocks

Question 25

Slopes are ________ systems.

Answer 25

Dynamic

Question 26

When does movement occur on slopes?

Answer 26

When driving forces overcome resisting forces.

Question 27

What aids gravity on slopes?

Answer 27

Oversteepness, water content, lack of vegetation, and human disturbances

Question 28

What are planes of weakness?

Answer 28

joints, fractures, faults; prominent bedding; foiliation/ schistosity; cracks from ice wedging, roots, etc.

Question 29

Q: Planes should be perpendicular or parallel to slopes for mass movement?

Answer 29

A: parallel

Question 30

What is creep?

Answer 30

Loose material moving slowly downslope

Question 31

What is solifluction?

Answer 31

Creep in very cold climates; permafrost, upper layer of soil thaws, liquefies when waterlogged, and flows any direction

Question 32

What is rockfall?

Answer 32

failure of steep or vertical slope

Question 33

What are slides?

Answer 33

Single, intact mass of material

Question 34

What type of slide fails along a slip plane = layer of weakness?

Answer 34

block slide

Question 35

What are slumps?

Answer 35

concave slip plane... chair shape result

Question 36

What are flows?

Answer 36

Movement like viscous fluid

Question 37

Name three types of flows:

Answer 37

earthflows, mudflows, and lahars

Question 38

Describe earthflows:

Answer 38

relatively dry, thick, slow

Question 39

Describe mudflows:

Answer 39

fine-grained, H20 rich, slurry, rapid movement, follow cloudbursts, major storms

Question 40

Describe lahars:

Answer 40

catastrophic mudflows, water from ice or storm events

Question 41

What are debris flows?

Answer 41

Move as a coherent mass. Water-saturated, very fast

Question 42

Where are three evidences of earlier failure seen?

Answer 42

air photos, satellite imagery, topographic maps

Question 43

How can you prevent mass movements by nonstructural methods?

Answer 43

Adding vegetation or chemical binding agents.

Question 44

How can you prevent mass movements by structural methods?

Answer 44

Reducing slope angle, unloading (decreasing) slope weight, terracing (benching), slope supports, and draining water away.

Question 45

What's the ratio in the cost-benefit analysis of slope support?

Answer 45

$1 spent will save $10 - $2000

Question 46

What are the characteristics of flash floods in arid climates?

Answer 46

Little vegetation, steep slopes, and "distant" local storms.

Question 47

How much groundwater/day do humans require?

Answer 47

1 gallon/day

Question 48

How many gallons of water is used in North America per day?

Answer 48

400 million

Question 49

Groundwater _________ use exceeds recharge by infiltration.

Answer 49

"Overdraft"

Question 50

What is an aquifer?

Answer 50

A body of rock or regolith that is water saturated, porous, and permeable.

Question 51

What is another name for the zone of aeration? What is it?

Answer 51

Vadose zone. Pores with both water and air.

Question 52

What is another name for the zone of saturation? What is it?

Answer 52

Phreatic zone. Water fills all porosity.

Question 53

What does well pumping form in aquifer depletion?

Answer 53

Cone of depression

Question 54

Where is a place with lots of aquifer depletion?

Answer 54

San Joaquin Valley

Question 55

Land subsidence can result from what?

Answer 55

Groundwater overdraft

Question 56

What is a rupture?

Answer 56

An elastic rebound for energy release.

Question 57

What are the three types of stress?

Answer 57

Tensional stress, compressional stress, and shear stress.

Question 58

Which boundary is tensional stress?

Answer 58

Divergent boundaries

Question 59

Which boundary is compressional stress?

Answer 59

Convergent boundaries

Question 60

Which boundary is shear stress?

Answer 60

Transform boundaries

Question 61

What is the result of tensional stress?

Answer 61

Weak rocks and quakes shallow and small

Question 62

What is the result of compressional stress?

Answer 62

Rocks stronger and quakes deeper

Question 63

What is the result of shear stress?

Answer 63

Brittle vs plastic deformation; rupture and rebound

Question 64

Where is a zone of compressional stress found?

Answer 64

Benioff-Watadi Zone

Question 65

Where are locations of intraplate earthquakes?

Answer 65

New Madrid, Missouri and Charleston, South Carolina.

Question 66

Are intraplate earthquakes generally shallow or deep?

Answer 66

Shallow

Question 67

What kind of rocks are needed for good energy transmission?

Answer 67

Cold, brittle rocks

Question 68

How many miles were shaken in the 1811-12 Madrid fault line earthquake?

Answer 68

2 million sq. mi.

Question 69

What are the three discontinuities in rocks?

Answer 69

Fractures, joints, faults