Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Geology > Lecture 8 - Earthquakes/Tectonics > Flashcards

Lecture 8 - Earthquakes/Tectonics Flashcards

1
Q

What is the driving force of plate movement

A

Gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is slab pull?

A

pulling of crust into mantle by down-going slab during subduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is slab-push

A

Pushing of crust resulting from elevated position of oceanic ridge system, causing crust to gravitationally slide down flanks of ridge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Divergent margins can occur where and lead to what?

A

can occur within ocean or within continent but always leads to creation of ocean basin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Divergent margins are marked by

A

faults, volcanoes, and uplift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are faults?

A

Faults are fractures in bedrock along which movement has occurred.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are joints?

A

fractures or crack in bedrock along which essentially no movement has occurred

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What type of fault is formed exclusively in divergent plate margins?

A

Normal fault

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Normal faults result in thinning of the crust =

A

extension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

True or false: There is igneous activity at transform margins

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens at transform margins?

A

Plates slide horizontally past one another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What type of fault happens at transform margins?

A

Transform fault

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Convergent margins are where plates move toward each other. What type of faults happen there?

A

Reverse faults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens at ocean-ocean convergence

A

Marked by depe ocean trench and volcanic island arc (subduction zone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens at ocean-continent convergence

A

Marked by ocean trench, volcanic arc and mountain belt (subduction zone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens at continent-continent convergence?

A

Marked by mountain belts and thrust faults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Not al rocks break (fault). THey can also undergo

A

ductile deformation (flow) and folding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

If fold happens in two directions at the same time it can gives us:

A

Domes: unwarped displacement of rocks
Basin: downwarped displacement of rock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How are earthquakes produced?

A

By the movement of rock bodies past other. THe stress has to exceed the strength of the rocks in brittle manner (cohesion is lost)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

The loci of the earthquake movements are

A

faults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is fault creep

A

slow migration of crust along fault plane; weak vibrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Rocks bend and store elastic energy which builds-up strain. How is frictictional resistance holding the rocks together overcome?

A

Earthquakes

23
Q

What is an earthquake

A

Vibration of earth produced by rapid release of energy stored in rock subjected to stress

24
Q

What is the focus or hypocenter?

A

Energy released radiates in all directions from its source

25
Q

What is the epicenter

A

Location on the surface directly above the focus

26
Q

What is magnitude

A

Energy measured in in the form of waves

27
Q

What is intesity

A

Energy felt/observed

28
Q

What is seismology

A

Study of earthquake waves

29
Q

What are seismograms

A

Records of seismic waves from seismographs

30
Q

What do seismograms rely on

A

inertia of suspended weight to record motion

31
Q

What’s a P wave

A

Compressional, 6-8km/s parallel to direction of movement (slinky)

32
Q

What an S-wiave

A

shear. 4-5 lm/s. Perpendicular to direction of movement (rope)

33
Q

What do s waves not pass through

A

Liquids

34
Q

What do surface waves result in

A

horizontal and vertical orbital motions with long period and great amplitude; travel along outer parts of Earth

35
Q

What are the 2 types of surface waves

A

Love waves: side to side

Rayleigh (R) waves: like an ocean wave.

36
Q

What are the most destructive waves

A

R waves

37
Q

How is the epicenter located

A

Using the difference in velocites of P & S waves . The point where all 3 circles of the different stations interesect is the earthquake epicenter

38
Q

Major earthquake zones include

A

Circum-pacific belt, alpine-himilayan chain, and oceanic ridge system….. aka plate boundaries

39
Q

90% of quakes happen at what depths

A

<100 km depth

40
Q

What scale was developed using Califormnia buildings as its standard

A

Modified Mercalli Intensity Scale

41
Q

what is the 1st magnitude number that comes out

A

Richter scale

42
Q

What is the richter scale

A

Based on the amplitude of the largest seismic wave recorded 100km from epicenter

43
Q

What is the moment-magnitude scales

A

Gauges quake total energy

44
Q

What 3 factors influence the amount of damage attributable to earthquakes

A

intensity/duration of vibration
natural of material upon which the structure rests
design of the structure

45
Q

What is liquefaction

A

unconsolidated materials saturated with water converts into mobile fluid

46
Q

What is seiches

A

The rhythmic sloshing of water in lakes, reservoirs, and enclosed basins

47
Q

what 3 rock behaviour forces are used to try and predict the way earthquakes will happen/behave

A

1) If deformed materials return to original shape after stress removal, they are behaving elastically (however once the stress exceeds the elastic limit of a rock, it deforms permanently
2) Ductile deformation involves bending plastically
3) Brittle deformation involves fracturing/rupture

48
Q

In terms of rock behaviour, what is stress?

A

Results in irreversible changes in shape or size of rock (applied force)

49
Q

In terms of rock behaviour, what is strain

A

Change in size or shape in response to stress (deformation)

50
Q

How can we predict earthquakes in terms of physical changes in crust?

A

Rocks under stress begin to dilate (expand in volume)

51
Q

What are some short term earthquake preidctions

A 
Swarms of foreshocks
tilt/bulge in crust/land surface
changes in seismic wave velocity
strain monitors
plaeoseismology
52
Q

What are some long term earthquake predictions

A 
Seismic gaps (locked segments of a fault which have been "quiet")
Strain monitors and ground deformation
53
Q

How is Ottawa/Gatineau area similar to the area of Kathmandu, Nepal

A

We live on a deposition of very fine grain unconsolidated material = weak

Geology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions