2 - Exploring Earth's Interior

Continental crust is __________, oceanic crust is ___________, the mantle is ___________________, the outer core is made of _______________ and the inner core is made of ________________.

felsic, mafic, mafic/ultramafic, liquid iron, solid iron

If you have a boundary between _____________ and ____________ rocks, then waves will be __________ and/or ______________ (will go through material but will emerge bent)

igneous, sedimentary, reflected, refracted

The geotherm is always ____________ with increased depth, the biggest jumps occur at the boundaries between the ________ and ______ and the ________ and the _______ (looks like head and shoulder)

increasing, crust, LVZ, lower mantle, outer core

If the Earth had no changes in pressure or composition with depth (________________) seismic waves would travel a _____________ path

isotropic, straight

The outer core is ____________ while the inner core is __________

liquid, solid

S and P waves both travel fastest at the base of the ____________, while S waves travel slowest in _______________ and P waves travel slowest in _____________

lower mantle, loose sediment, water

The inner core was discovered bu the study of seismic waves from _______________

nuclear explosions

The decrease of velocity in the low velocity zone has to do with __________________

plate tectonics

The body waves (P and S) have another characteristic that affect ______________: when they move through layers of rock, they are __________ or __________

shaking, reflected, refracted

geothermal gradient

the rate of change in temperature with increasing depth

Seismic waves travel faster in _________ material then in __________, and faster in _______ material than in __________ material.

solid, liquid, cold, hot Faster in ice than soup

seismic tomography

uses seismic waves collected from all over the world to create a computer-generated, three-dimensional image of Earth's interior

the __________ of seismic waves increases with __________

velocity, depth

One common feature of different wave types is that the __________ at which they travel depends on the _____________ they pass through, for example ______ and ______ waves travel faster through ____________ than through ____________

velocity, material/rock, P, S, basalt, granite

melting curve

Indicates the temperature at which materials melt as depth increases in the Earth, mantle rock up until outer core, iron alloy beyond that

The boundary between the crust and mantle

Mohorovicic discontinuity (Moho)

Whenever a _____ or _____ wave is _____________ or ___________ some of the ____________ of one type is _____________ into waves of the other type

P, S, reflected, refracted, energy, converted

In the LVZ, the melting curve for mantle rock falls ______ the geotherm, other wise it is always above

below (melted)

The melting curve for iron alloy falls _________ the geotherm in the outer core and _________ the geotherm in the inner core.

below, above

Even though P waves ____________ through liquid, they travel much _________, explaining their huge decrease in _____________ at the boundary between the lower mantle and _________ outer core. This same phenomenon explains the slight jump between velocities at the boundary between the ___________ and ______ _________

can, slower, velocity, liquid, outer core, solid, inner core

Earth is layered, having variation due to rock ____________, ____________, and ___________ that together cause seismic waves to ____________ (bend) when transmitted between different rock layers.

composition, elasticity, temperature, refract

The four layers of the Earth

crust, mantle, outer core, inner core

Seismic waves traveling only in the _________ reach a _______ seismograph first, since they have a shorter distance to travel

crust, nearby

Seismic waves through the interior follow ________, not ________, paths. This is the case because the earth is made of different ____________, which conduct waves at different _________. The waves are ____________ at rock ___________, causing them to bend.

curved, straight, layers, velocities, refracted, discontinuities

Until the ____________ people thought Earth was all the same material, by measuring ___________________ we discovered that this is not actually the case

1930's, seismic waves

there are about ____________ big earthquakes per year that move the ____________ of the Earth

2, axis

Depths: Crust : __________ Upper Mantle: ___________ Lower Mantle: ___________ Outer Core: ___________ Inner Core: ___________

4-40 40-660 660-3000 3000-5000 5000-6371

In the velocity vs. depth profile, S wave velocity starts around ______ km/second and decreases slightly in the ________________(_______) between __________ km. It jumps up in the ______________ between ____________ km (between upper and lower mantle). It then slowly increases until it reaches the boundary between the _____________ and ____________ at which it disappears due to the ___________'s _________ state. Finally the waves reappear at their lowest velocity in the __________. This is possible because the energy is ______________ in passing through the ____________, allowing it to reappear as waves.

5, low velocity zone, LVZ, 100-200, transition zone, 400-600, lower mantle, outer core, outer core, liquid, inner core, transformed, liquid

In the velocity vs. depth profile, P wave velocity starts around ______ km/second and increase rapidly till 8 until decreasing slightly in the _________ between __________ km. It then jumps up in the ______________ between ____________ km (between upper and lower mantle). It then slowly increases until it reaches the boundary between the _____________ and ____________ at which it point it drops from 14 to 7, it slowly increases in the ___________ and jumps again in the ___________.

5.5, LVZ, 100-200, transition zone, 400-660, lower mantle, outer core, outer core, inner core

The radius of the Earth is ________________, out of which we can only drill down _________

6371 km, 12km

velocity vs. depth profile

Shows the depths at which seismic velocity suddenly changes and thus helped establish the principal layers and sublayers in the Earth.

geotherm

The change in temperature with increasing depth in the Earth.

As you go deeper into the interior of the Earth, _______________ increases, as silicate rocks < liquid iron < solid iron

density

If you know the velocity of an S or P wave, then with two distinct equations, you can calculate the ____________

density

When S waves traveling out from the ___________ of an earthquake reach the boundary between the ___________ and _________, they are ___________. This leads to the creation of _______ S-wave _____________________ which spans from ____________ degrees. This let us discover that the mantle is made of ___________ material, since S-waves cannot travel through _________.

focus, mantle, outer core, reflected, 1, shadow-zone, 103-103, liquid, liquids

When P waves traveling out from the ___________ of an earthquake reach the boundary between the ___________ and _________, they are ___________. This leads to the creation of ________ p-wave _____________________ which span from ____________ degrees. This let us discover that the mantle is made of ___________ material than the outer core.

focus, mantle, outer core, refracted, 2, shadow-zones, 103-143, different

Seismic waves traveling for most of their path in the ________ reach a _______ seismograph first, since they travel faster than those in the _______.

mantle, distant, crust

An earthquake generates all seismic wave types, including ________ and __________ __________ waves, and ____________ and __________ ___________ waves

primary, secondary, body, love, rayleigh, surface