Chapter 9: Earth's Interior

T or F: All mountains have roots when they have reached isostatic equilibrium.

True

T or F: Seismic waves travel faster in oceanic crust than in continental crust.

True

T or F: The Earth's magnetic field has flipped its polarity many times in Earth's history.

True

T or F: The asthenosphere may be partially melted.

True

T or F: The presence of an S-wave shadow zone implies that the earth's outer core is liquid

True

T or F: The rise of the surface of the crust after removal of glacial ice is known as crustal rebound.

True

T or F: The two main heat sources of the Earth are the primordial heat and the radiogenic heat.

True

T or F: The ultra-low-velocity zone (ULVZ) may be caused by the core partially melting overlying mantle rock.

True

T or F: Within the lithosphere the temperature gradient is lower in the continents and higher at the oceanic ridges.

True

T or F: The earth's core is made up of silicates.

False

The P-wave shadow zone can be explained by the refraction of P-waves at the ____ boundary. A) core-mantle B) asthenosphere-lithosphere C) Moho D) inner core-outer core

A

The ____ is a low velocity seismic zone. A) asthenosphere B) lower crust C) core D) outer core

A

The _____ powers most geological processes and drives plate tectonics. A) Earth's internal heat B) sun C) rock cycle D) earthquake

A

The bending of seismic waves as they pass from one material to another is called seismic _____. A) refraction B) reflection C) deflection D) attenuation

A

The crust and uppermost mantle form the _____. A) lithosphere B) asthenosphere C) continent D) D" layer

A

The rise of the crust after removal of erosion is called _____. A) crustal rebound B) tectonic uplift C) subduction D) dynamic adjustment

A

The rock record for tens of millions of years indicates that the earth's magnetic field _____. A) reverses polarity B) is constant in strength and polarity C) did not come into existence until about 1 million years ago D) has steadily weakened and will be gone in another 10 million years

A

_____ predicts that the higher a mountain range extends above sea level the deeper it extends into the mantle. A) Isostatic adjustment B) Mantle convection C) Mohorovicic discontinuity D) Subducting oceanic lithosphere

A

Seismic body waves _____ through continental crust relative to oceanic crust. A) travel faster B) travel slower C) travel at same velocity

B

The boundary that separates the crust from the mantle is the _____ discontinuity. A) mantle B) Moho C) athenospheric D) shadow

B

15. The Earth's heat from depth is being brought up by both _____ and conduction. A) thermal decay B) global warming C) convection D) seismic waves

C

The upper mantle consists of ________. A) granite B) basalt C) ultramafic rocks D) sedimentary rocks

C

As lava cools, a record of the earth's _____ field is permanently trapped in the rock. A) gravity B) seismic C) isotatic D) magnetic

D

What is the asthenosphere? A) It is the surface that separates the crust from the mantle. B) It is the zone that separates the continental crust from the oceanic crust. C) It is in the surface that separates the inner and outer core. D) It is the zone of weakness in the mantle on which the lithosphere mov

D

___ indicates that the outer core of the earth is a liquid. A) Density calculations B) Studies of meteorites C) The P-wave shadow zone D) The S-wave shadow zone

D

T or F: Lithosphere is another name for the crust of the earth.

False

T or F: S-waves are compressional waves in which the rock vibrates back and forth in the direction of wave propagation.

False

T or F: Seismic reflection is the bending of seismic waves as they pass from one material to another having different density

False

T or F: The Moho separates the lithosphere from the asthenosphere

False

T or F: The composition of the upper mantle is felsic.

False