Earth's Interior Flashcards

(31 cards)

1
Q

What is one of body waves characteristics that affect shaking

A

They reflect and/or refract through layers of rock

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2
Q

What does refraction mean?

A

The wave/ light BENDS

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3
Q

What type of waves do earthquakes generates?

A

ALL WAVE TYPES

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4
Q

What happens when a wave is reflected or refracted?

A

Some of the energy of one type is converted to waves of the other type

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5
Q

What do waves of different types have in common?

A

The velocity at which they travel DEPENDS ON THE MATERIAL (rocks) THAT THEY PASS THROUGH

P and S waves travel more rapidly through basalt than through granite
=seismic waves travel faster in a solid than a liquid

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6
Q

What does the velocity of seismic waves depend on?

A

Increase with depth

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7
Q

What path do seismic waves follow?

A

The paths through the interior are curved

DO NOT FOLLOW A STRAIGHT PATH

earth is layered and made of diff materials that conduct P and S waves at diff velocities
bend as they go through each layer

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8
Q

What is the basic data of seismology

A

Travel times

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9
Q

How many seismographs and clocks enable seismologists to measure the travel times of P, S, and surface waves precisely

A

Thousands

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10
Q

What do travel times depend on?

A

Their velocities

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11
Q

Which seismic waves reach a nearby seismograph first?

A

Waves traveling only in the crust

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12
Q

What is the crust-Mantle boundary called

A

Moho

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13
Q

Which seismic waves reach a distant seismograph first?

A

Waves traveling most of their path in the mantle

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14
Q

Is the outer core solid or liquid?

A

liquid

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15
Q

What do you need to know travel data?

A
Total travel time
Speed limit (speed of seismic waves in rocks inside Earth)
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16
Q

How does path change?

A

The velocity changes with depth in the Earth

17
Q

What is the p-wave shadow zone?

A

Earth has a core made of a material different from that of the overlying mantle

waves are bent downward
downward bending means that the waves travel more slowly in the core than in the mantle

P-waves move much more slowly in liquids than in solids

18
Q

What is the s-wave shadow zone?

A

Other side of the core

Proved the outer core is liquid

when they hit the core, the fail to emerge from the other side

19
Q

PP waves

A

P waves that bounce off the Earth’s surface back into Earth

20
Q

SS

A

S waves that reflect back into Earth

21
Q

ScS

A

S wave that reflected at the outer core/mantle boundary back to the surface

22
Q

PcP

A

P waves that are reflected at the outer core/mantle boundary

23
Q

PKP

A

P waves that penetrate the outer core

24
Q

PKIKP

A

P waves that penetrate the inner core

25
How are PP, SS, PcP, ScS, PKP, PKIKP differentiated?
Differentiated from one another by their amplitude and frequency
26
What is geotherm
indicated the change in temperature as depth increases in the Earth
27
What is the melting curve
indicates the temperature at which materials melt as depth increases in the Earth
28
what is the geothermal gradient
the rate of change in temperature with depth e.g. 20 C/km
29
How to determine the p-wave velocity
sqrt ((K + (4/3u))/p) K=the bulk modulus (the modulus incompressibility) of a material u=the shear modulus (modulus of rigidity) p=the density travel speeds between 1 and 14 km/sec the slower numbers
30
How to determine the s-wave velocity
sqrt (u/p) u=the shear modulus (modulus of rigidity) p=the density
31
What is seismic tomography
uses travel times to create 3-D images of Earth's Interior reveals features in the mantle clearly associated with mantle convection hot and cold inside Earth