EARTH'S INTERIOR MEGA PACKET MC

1. Which two Earth layers are separated by the Moho boundary? A) rigid mantle and plastic mantle B) outer core and stiffer mantle C) stiffer mantle and asthenosphere D) crust and rigid mantle 2. A model of Earth's internal structure is shown below. Analysis of which type of data led to the development of this model? A) seismic waves B) depth of Earth's oceans C) electromagnetic radiation D) isobar gradients

3. Base your answer to the following question on the diagram of Earth shown below. Letters B, C, and D represent layers of Earth. Letter Q represents a location on Earth's surface. Which letter best represents Earth's mantle? A) Q B) B C) C D) D 4. Base your answer to the following question on "the cross section below, which shows the paths of seismic waves traveling from an earthquake epicenter through the different layers of Earth's interior. " No P-waves or S-waves are received in the shadow zone because A) P-waves are absorbed and S-waves are refracted by Earth's outer core B) P-waves are refracted and S-waves are absorbed by Earth's outer core C) both the P-waves and S-waves are refracted by Earth's outer core D) both the P-waves and S-waves are absorbed by Earth's outer core

5. Which part of Earth s interior is inferred to have convection currents that cause tectonic plates to move? A) rigid mantle B) asthenosphere C) outer core D) inner core EARTH'S INTERIOR MEGA PACKET MC

6. The graph below shows the different velocities of P-waves and S-waves through Earth's interior. Which cross section best shows the inferred thickness of Earth's interior layers that cause these different velocities? A) B)

C) D) 7. Earth s outer core is best inferred to be A) liquid, with an average density of approximately 4 g/cm 3 B) liquid, with an average density of approximately 11 g/cm 3 C) solid, with an average density of approximately 4 g/cm 3 D) solid, with an average density of approximately 11 g/cm 3 8. Why is Earth s outer core inferred to be a liquid? A) P-waves can pass through the outer core. B) P-waves cannot pass through the outer core. C) S-waves can pass through the outer core. D) S-waves cannot pass through the outer core. 9. From the top of the stiffer mantle to the center of Earth, the rock material is inferred to be A) solid all the way to the center of the inner core B) solid, then liquid to the center of the inner core C) solid, then liquid, then solid again to the center of the inner core D) solid, then liquid, then gaseous to the center of the inner core 10. The fact that S-waves are unable to travel through the Earth's outer core supports the inference that the outer core is A) composed of iron and nickel B) more dense than the inner core C) hotter than the rock's melting point D) in the solid state of matter

11. The rock between 2,900 kilometers and 5,200 kilometers below the Earth's surface is inferred to be A) an iron-rich solid B) an iron-rich liquid C) a silicate-rich solid D) a silicate-rich liquid 12. Which part of the Earth is most likely a liquid zone? A) inner core B) outer core C) mantle D) crust 13. In the Earth's interior, which zone has a temperature higher than its melting point? A) crust B) stiffer mantle C) inner core D) outer core 14. The analysis of seismic data from an earthquake shows that some locations received both P-waves and S-waves, but other locations received only P -waves. What is the best inference that can be made from these observations? A) A zone of liquid rock exists within the Earth. B) Iron in some rocks prevents S-waves from traveling. C) Some seismographs are more sensitive than others. D) S-waves are very weak. 15. Seismic studies of the Moon have helped scientists to make inferences about A) water erosion on the Moon B) weathering on the Moon's surface C) radioactivity of the Moon's surface rocks D) the Moon's interior 16. Compared to the oceanic crust, the continental crust is usually A) thicker, with a less dense granitic composition B) thicker, with a more dense basaltic composition C) thinner, with a less dense granitic composition D) thinner, with a more dense basaltic composition 17. Compared to Earth s continental crust, Earth s oceanic crust is A) thinner and more dense B) thinner and less dense C) thicker and more dense D) thicker and less dense 18. Beneath which surface location is Earth's crust the thinnest? A) East Pacific Ridge B) the center of South America C) Old Forge, New York D) San Andreas Fault

19. Base your answer to the following question on "the map below which shows the locations of deep-sea core drilling sites numbered 1 through 4. The approximate location of the diverging plate at the East Pacific Ridge is shown by a dashed line. Point A is located on the East Pacific Ridge. " Compared to the thickness and density of the continental crust of South America, the oceanic crust of the Pacific floor is A) thinner and less dense B) thinner and more dense C) thicker and less dense D) thicker and more dense 20. Which statement most accurately compares Earth s crust and Earth s mantle? A) The crust is thinner and less dense than the mantle. B) The crust is thinner and more dense than the mantle. C) The crust is thicker and less dense than the mantle. D) The crust is thicker and more dense than the mantle.

21. Base your answer to the following question on " the map below, which shows seismic stations X, Y, and Z that have recorded seismic waves from the same earthquake. The distances from seismic stations X and Y to the earthquake epicenter have been drawn on the map. Locations A, B, C, and D represent possible earthquake epicenters. The distance from seismic station Z to the earthquake epicenter has been deliberately omitted. " If the earthquake's focus was 2 kilometers below Earth's surface, the earthquake occurred in the A) lithosphere B) asthenosphere C) stiffer mantle D) outer core 22. Compared to Earth's oceanic crust, Earth's continental crust is A) thinner and composed of granite B) thinner and composed of basalt C) thicker and composed of granite D) thicker and composed of basalt 23. Where is the thickest part of the Earth's crust? A) at the edge of continental shelves B) at mid-ocean ridges C) under continental mountain ranges D) under volcanic islands

24. Where is the thickest part of the Earth's crust? A) at mid-ocean ridges B) at transform faults C) under continental mountain ranges D) under volcanic islands EARTH'S INTERIOR MEGA PACKET MC 25. On the map below, locations A and B are reference points on the Earth's surface. Crustal thickness was measured beneath a line from A to B. Which graph best represents the thickness of the Earth's crust from location A to location B? A) B) C) D)

26. The diagram below represents a cross section of a portion of the Earth's crust. EARTH'S INTERIOR MEGA PACKET MC Which statement about the Earth's crust is best supported by the diagram? A) The oceanic crust is thicker than the mantle. B) The continental crust is thicker than the oceanic crust. C) The continental crust is composed primarily of sedimentary rock. D) The crust is composed of denser rock than the mantle is. 27. The interface between the crust and mantle of the Earth is generally much deeper under continental surfaces than under ocean surfaces. This information indicates that A) the interface varies in an unpredictable manner B) oceanic crust is thicker than continental crust C) continental crust is thicker than oceanic crust D) both oceanic and continental crusts are approximately the same thickness 28. To get sample material from the mantle, drilling will be done through the oceanic crust rather than through the continental crust because oceanic crust is A) more dense than continental crust B) softer than continental crust C) thinner than continental crust D) younger than continental crust

29. The pie graph below represents the composition, in percent by mass, of the chemical elements found in an Earth layer. The composition of which Earth layer is represented by the pie graph? A) crust B) outer core C) troposphere D) hydrosphere

30. Base your answer to the following question on the cross section below and on your knowledge of Earth science. The cross section represents the distance and age of ocean-floor bedrock found on both sides of the Mid-Atlantic Ridge. Which map best represents the pattern of magnetic polarity in the minerals of ocean-floor bedrock on each side of the Mid-Atlantic Ridge? A) B) C) D) 31. Which minerals contain the two most abundant elements by mass in Earth s crust? A) fluorite and calcite B) magnetite and pyrite C) amphibole and quartz D) galena and sulfur

32. The most abundant metallic element by mass in Earth's crust makes up 8.23% of the crust. Which group of minerals all normally contain this metallic element in their compositions? A) garnet, calcite, pyrite, and galena B) biotite mica, muscovite mica, fluorite, and halite C) talc, quartz, graphite, and olivine D) plagioclase feldspar, amphibole, pyroxene, and potassium feldspar 33. Which mineral is most frequently found in both granitic continental crust and basaltic oceanic crust? A) olivine B) potassium feldspar C) plagioclase feldspar D) quartz 34. The interior of Earth between a depth of 5200 kilometers and 6300 kilometers is inferred to be composed mostly of A) silicon and iron B) silicon and oxygen C) iron and lead D) iron and nickel 35. Which element is most abundant in Earth's crust? A) nitrogen B) hydrogen C) oxygen D) silicon 36. The basaltic bedrock of the oceanic crust is classified as A) felsic, with a density of 2.7 g/cm 3 B) felsic, with a density of 3.0 g/cm 3 C) mafic, with a density of 2.7 g/cm 3 D) mafic, with a density of 3.0 g/cm 3 37. Which group of elements is listed in increasing order based on the percent by mass in Earth s crust? A) aluminum, iron, calcium B) aluminum, silicon, magnesium C) magnesium, iron, aluminum D) magnesium, silicon, calcium 38. Compared to the continental crust, the oceanic crust is A) less dense and less felsic B) less dense and less mafic C) more dense and more felsic D) more dense and more mafic 39. The two most abundant elements by mass in Earth s crust are oxygen and A) potassium B) hydrogen C) nitrogen D) silicon 40. The observed difference in density between continental crust and oceanic crust is most likely due to differences in their A) composition B) thickness C) porosity D) rate of cooling

41. Base your answer to the following question on "the map below. The map shows the continents of Africa and South America, the ocean between them, and the ocean ridge and transform faults. Locations A and D are on the continents. Locations B and C are on the ocean floor. " Which table best shows the relative densities of the crustal bedrock at locations A, B, C, and D? A) B) C) D) 42. What are the two most abundant elements by mass found in Earth's crust? A) aluminum and iron B) sodium and chlorine C) calcium and carbon D) oxygen and silicon

43. Base your answer to the following question on the cross section below, which shows a portion of Earth s crust and upper mantle near a mid-ocean ridge. If crust 2 represents basalt with normal magnetic polarity, what does crust 3 most likely represent? A) igneous rock with normal magnetic polarity B) igneous rock with reversed magnetic polarity C) sedimentary rock with normal magnetic polarity D) sedimentary rock with reversed magnetic polarity 44. Compared to continental crust, oceanic crust is A) less dense, more mafic, and thinner B) less dense, more felsic, and thicker C) more dense, more mafic, and thinner D) more dense, more felsic, and thicker 45. What is the approximate percentage by volume of oxygen in the crust of the Earth? A) 20% B) 30% C) 70% D) 90% 46. Which two elements make up the greatest volume of the Earth's crust? A) silicon and potassium B) silicon and iron C) iron and nickel D) oxygen and potassium 47. Compared to the continental crust, the oceanic crust is A) thicker B) more dense C) more granitic D) more felsic 48. The most abundant element in the Earth's crust is A) nitrogen B) oxygen C) silicon D) hydrogen 49. In the diagram below, letters A and B represent locations near the edge of a continent. A geologist who compares nonsedimentary rock samples from locations A and B would probably find that the samples from location A contain A) more granite B) more basalt C) more fossils D) the same minerals and fossils 50. Oxygen is the most abundant element by volume in the Earth's A) inner core B) troposphere C) hydrosphere D) crust 51. Most of the oceanic crust is composed of rock material similar to A) basalt B) granite C) sandstone D) limestone

52. Compared to the continental crust of central North America, the oceanic crust of the Mid-Atlantic Ridge is A) younger B) thicker C) less dense D) more felsic 53. Which element in the Earth's crust makes up the largest volume of most minerals? A) oxygen B) nitrogen C) hydrogen D) iron 54. How does the oceanic crust compare to the continental crust? A) The oceanic crust is thinner and contains less basalt. B) The oceanic crust is thinner and contains more basalt. C) The oceanic crust is thicker and contains less basalt. D) The oceanic crust is thicker and contains more basalt. 55. Which element is most abundant by mass in the Earth's crust? A) nitrogen B) oxygen C) silicon D) iron EARTH'S INTERIOR MEGA PACKET MC 56. The pie graph below represents the composition, in percent by mass, of the chemical elements found in an Earth layer. The composition of which Earth layer is represented by the pie graph? A) crust B) outer core C) troposphere D) hydrosphere

57. What are the four most abundant elements, by volume, in the Earth's crust? A) oxygen, potassium, sodium, and calcium B) hydrogen, oxygen, nitrogen, and potassium C) aluminum, iron, silicon, and magnesium D) aluminum, calcium, hydrogen, and iron 58. Which two elements listed below are most abundant by weight in the Earth's crust? A) silicon and oxygen B) hydrogen and iron C) oxygen and magnesium D) hydrogen and calcium 59. The pressure at the interface between Earth's outer core and inner core is inferred to be A) 0.2 million atmosphere B) 1.5 million atmospheres C) 3.1 million atmospheres D) 3.6 million atmospheres 60. What are the inferred pressure and temperature at the boundary of Earth's stiffer mantle and outer core? A) 1.5 million atmospheres pressure and an interior temperature of 4950 C B) 1.5 million atmospheres pressure and an interior temperature of 6200 C C) 3.1 million atmospheres pressure and an interior temperature of 4950 C D) 3.1 million atmospheres pressure and an interior temperature of 6200 C 61. What caused the interior of Earth to separate into layers? A) a decrease in the rate of rotation of Earth B) the gravitational pull on materials of varying densities C) variations in heating by the Sun due to Earth's tilt D) collisions with meteors and comets 62. The inferred temperature and pressure of Earth's interior at a depth of 3,000 kilometers are approximately A) 1000 C and 0.5 million atmospheres B) 1000 C and 1.0 million atmospheres C) 5000 C and 1.5 million atmospheres D) 5000 C and 3.0 million atmospheres

A) B) EARTH'S INTERIOR MEGA PACKET MC 63. Which graph best shows the range of density in each of Earth's layers? C) D) Base your answers to questions 64 through 67 on the diagram below, which represents zones of Earth's interior, identified by letters A through E. The scale shows depths below Earth's surface, measured in kilometers. 64. The Moho is a boundary located in zone A) A B) B C) E D) D 65. What is the approximate thickness of zone C? A) 650 km B) 1600 km C) 2250 km D) 2900 km 66. Which zone of Earth's interior has a density closest to the densities of the other terrestrial planets? A) zone A B) zone E C) zone C D) zone D

67. Which zone is characterized by partially melted rock and large-scale convection currents? A) zone A B) zone B C) zone C D) zone E 68. The inferred temperature at the interface between the stiffer mantle and the asthenosphere is closest to A) 1000 C B) 2500 C C) 4500 C D) 5000 C Base your answers to questions 69 through 71 on the cross section below, which shows the boundary between two lithospheric plates. Point X is a location in the continental lithosphere. The depth below Earth's surface is labeled in kilometers. 69. Compared to the continental crust, the oceanic crust is A) less dense and thinner B) less dense and thicker C) more dense and thinner D) more dense and thicker 70. Point X is located in which Earth layer? A) rigid mantle B) stiffer mantle C) asthenosphere D) outer core 71. The temperature of the asthenosphere at the depth where melting first occurs is inferred to be approximately A) 100 C B) 1300 C C) 4200 C D) 5000 C

72. The diagram below shows the cutaway views of the inferred interior layers of the planets Mercury and Venus. What is the reason for the development of the interior layers of these two planets? A) Impact events added the mantle rock above the cores. B) Heat from the Sun melted the surface rocks to form the mantles above the cores. C) Gravity separated the cores and mantles due to their density differences. D) Rapid heat loss caused the cores to solidify before the mantles. 73. Which combination of temperature and pressure is inferred to occur within Earth s stiffer mantle? A) 3500 C and 0.4 million atmospheres B) 3500 C and 2.0 million atmospheres C) 5500 C and 0.4 million atmospheres D) 5500 C and 2.0 million atmospheres 74. What happens to the density and temperature of rock within Earth s interior as depth increases? A) density decreases and temperature decreases B) density decreases and temperature increases C) density increases and temperature increases D) density increases and temperature decreases 75. Which temperature is inferred to exist in Earth s plastic mantle? A) 2000 C B) 3000 C C) 5000 C D) 6000 C 76. What is Earth s inferred interior pressure, in millions of atmospheres, at a depth of 3500 kilometers? A) 1.9 B) 2.8 C) 5500 D) 6500 77. Why does the oceanic crust sink beneath the continental crust at a subduction boundary? A) The oceanic crust has a greater density. B) The oceanic crust is pulled downward by Earth s magnetic field. C) The continental crust has a more mafic composition. D) The continental crust is pulled upward by the Moon s gravity.

A) B) EARTH'S INTERIOR MEGA PACKET MC 78. Which graph best shows the inferred density of Earth's interior as depth increases from the upper mantle to the lower mantle? C) D) 79. Which statement correctly describes the density of Earth s mantle compared to the density of Earth s core and crust? A) The mantle is less dense than the core but more dense than the crust. B) The mantle is less dense than both the core and the crust. C) The mantle is more dense than the core but less dense than the crust. D) The mantle is more dense than both the core and the crust. 80. Which conditions normally can be found in Earths asthenosphere, producing a partial melting of ultramafic rock? A) temperature = l,000 C; pressure = 10 million atmospheres B) temperature = 2,000 C; pressure = 0.1 million atmospheres C) temperature = 3,500 C; pressure = 0.5 million atmospheres D) temperature = 6,000 C; pressure = 4 million atmospheres 81. What is the inferred temperature at the boundary between Earth s stiffer mantle and outer core? A) 2,500 C B) 4,500 C C) 5,000 C D) 6,200 C

82. When a continental crustal plate collides with an oceanic crustal plate, the continental crust is forced to move over the oceanic crust. What is the primary reason that the continental crust stays on top of the oceanic crust? A) Continental crust is less dense. B) Continental crust deforms less easily. C) Continental crust melts at higher temperatures. D) Continental crust contains more mafic minerals. 83. The density of Earth s crust is A) less than the density of the outer core but greater than the density of the mantle B) greater than the density of the outer core but less than the density of the mantle C) less than the density of both the outer core and the mantle D) greater than the density of both the outer core and the mantle 84. In which layer of Earth s interior is the pressure inferred to be 1.0 million atmospheres? A) outer core B) inner core C) rigid mantle D) stiffer mantle 85. Compared to Earth s crust, Earth s core is believed to be A) less dense, cooler, and composed of more iron B) less dense, hotter, and composed of less iron C) more dense, hotter, and composed of more iron D) more dense, cooler, and composed of less iron 86. Base your answer to the following question on " the diagram below, which shows a portion of Earth's interior. Point A is a location on the interface between layers. The temperature of rock at location A is approximately A) 600 C B) 1,000 C C) 2,600 C D) 3,000 C "

Base your answers to questions 87 and 88 on the diagram below, which shows a cutaway view of Earth in which the interior layers are visible. The paths of earthquake waves generated at point X are shown. A, B, C, and D are locations of seismic stations on Earth's surface, and point E is located in Earth's interior. EARTH'S INTERIOR MEGA PACKET MC 87. Both P-waves and S-waves were received at seismic stations A and B, but only P-waves were received at seismic stations C and D. Which statement best explains why this occurred? A) S-waves are much weaker than P-waves. B) S-waves travel faster than P-waves. C) The liquid outer core prevents S-waves from traveling to seismic stations C and D. D) The solid outer core prevents S-waves from traveling to seismic stations C and D. 88. The actual rock temperature at point E is inferred to be approximately A) 1,500ºC B) 2,900ºC C) 5,000ºC D) 6,200ºC 89. The pressure at the interface between the mantle and the outer core of Earth is inferred to be approximately A) 1.0 million atomspheres B) 1.4 million atmospheres C) 3.0 million atmospheres D) 3.4 million atmospheres

Base your answers to questions 90 through 94 on the diagram below which represents three cross sections of the Earth at different locations to a depth of 50 kilometers below sea level. The measurements given with each cross section indicate the thickness and the density of the layers. 90. The division of the Earth's interior into crust and mantle, as shown in the diagram, is based primarily on the study of A) radioactive dating B) seismic waves C) volcanic eruptions D) gravity measurements 91. Which statement about the Earth's mantle is confirmed by the diagram? A) The mantle is liquid. B) The mantle has the same composition as the crust. C) The mantle is located at different depths below the Earth's surface. D) The mantle does not exist under continental mountains. 92. Compared with the oceanic crust, the continental crust is A) thinner and less dense B) thinner and more dense C) thicker and less dense D) thicker and more dense 93. Which material is most likely to be found 20 kilometers below sea level at the continental mountain location? A) basalt B) granite C) shale D) limestone 94. In which group are the layers of the Earth arranged in order of increasing average density? A) mantle, crust, ocean water B) crust, mantle, ocean water C) ocean water, mantle, crust D) ocean water, crust, mantle

95. What is the approximate temperature at the mantle-outer core boundary? A) 1,500 C B) 4,500 C C) 5,000ºC D) 7,000ºC 96. An earthquake shear wave generally travels faster as the wave moves deeper into Earth's interior because greater depths have A) less confining pressure B) lower melting points C) greater rock density D) greater rock temperatures 97. In which area of Earth's interior is the pressure most likely to be 2.5 million atmospheres? A) asthenosphere B) stiffer mantle C) inner core D) outer core 98. Base your answer to the following question on the information and the cross section below. The cross section represents a possible model of the Moon's interior. Seismographs left on the Moon by astronauts have provided enough data to develop a model of the Moon's interior. Scientists believe that the Moon has a layered interior and that its crustal thickness varies greatly from one side of the Moon to the other. If the pressure, temperature, and density patterns of the Moon's interior are similar to those of the Earth's interior, which statement best describes the Moon's characteristics? A) Pressure, temperature, and density all increase with depth. B) Pressure increases with depth, but temperature and density remain the same. C) Pressure and temperature increase with depth, but density remains the same. D) Pressure, temperature, and density remain the same at all depths. 99. At a depth of 2,000 kilometers, the temperature of the stiffer mantle is inferred to be A) 6,500ºC B) 4,200ºC C) 3,500ºC D) 1,800ºC

100. As depth within the Earth's interior increases, the A) density, temperature, and pressure decrease B) density, temperature, and pressure increase C) density and temperature decrease, but pressure increases D) density decreases, but temperature and pressure increase 101. In which part of the Earth is a rock temperature of 2,000ºC most likely to occur? A) continental crust B) asthenosphere (plastic mantle) C) stiffer mantle D) outer core 102. Which statement best explains why the direction of some seismic waves changes sharply as the waves travel through the Earth? A) The Earth is spherical. B) Seismic waves tend to travel in curved paths. C) The temperature of the Earth's interior decreases with depth. D) Different parts of the Earth's interior have different densities. 103. The temperature at the center of the Earth is estimated to be A) 1,000 K B) 2,800 K C) 5,000 K D) 6,800 K 104. Approximately how far below the Earth's surface is the interface between the mantle and the outer core? A) 5 to 30 km B) 700 to 900 km C) 2,900 to 3,000 km D) 5,000 to 5,200 km 105. The source of energy for the high temperatures found deep within the Earth is A) tidal friction B) incoming solar radiation C) decay of radioactive materials D) meteorite bombardment of the Earth 106. What is the range of pressure in Earth's interior where rock with a density range of 9.9 to 12.2 g/cm 3 is found? A) 0.2 to 1.4 million atmospheres B) 0.8 to 2.3 million atmospheres C) 1.4 to 3.1 million atmospheres D) 2.3 to 3.5 million atmospheres 107. At 4,500 kilometers below the surface of the Earth, the pressure is estimated to be A) 1.4 million atmospheres B) 2.0 million atmospheres C) 2.8 million atmospheres D) 3.1 million atmospheres 108. Which statement about the Earth's mantle is correct? A) The density of the mantle is greatest 300 km below the Earth's surface. B) The highest temperatures within the Earth occur in the mantle. C) The greatest pressures within the Earth exist in the mantle. D) The temperature of the mantle 300 km below the Earth's surface is very near its melting point. 109. A part of which zone of the Earth's interior is inferred to have a density of 10.0 grams per cubic centimeter? A) crust B) mantle C) outer core D) inner core 110. What is the relationship between density, temperature, and pressure inside the Earth? A) As depth increases, density, temperature, and pressure decrease. B) As depth increases, density and temperature increase, but pressure decreases. C) As depth increases, density increases, but temperature and pressure decrease. D) As depth increases, density, temperature, and pressure increase.

111. In which zone of the Earth's interior is the melting point of the rock inferred to be lower than the actual temperature of the rock? A) outer core B) inner core C) crust D) mantle 112. In which group are the zones of the Earth's interior correctly arranged in order of increasing average density? A) crust, mantle, outer core, inner core B) crust, mantle, inner core, outer core C) inner core, outer core, mantle, crust D) outer core, inner core, mantle, crust 113. The rate of temperature increase below the Earth's surface is greatest between depths of A) 250 and 500 km B) 1500 and 2500 km C) 2500 and 3500 km D) 3500 and 4000 km 114. The temperature of rock located 1,000 kilometers below the Earth's surface is about A) 200 K B) 2,100 K C) 2,800 K D) 3,200 K 115. Which graph best represents the relationship between depth and density for the Earth's interior? A) B) C) D)

116. Base your answer to the following question on the passage below and on your knowledge of Earth science. Island Arcs Island arcs are long, curved chains of oceanic islands associated with seismic activity and mountain-building processes at certain plate boundaries. They occur where oceanic tectonic plates collide. Along one side of these island arcs, there is usually a long, narrow deep-sea trench. At island arcs, the denser plate is subducted and is forced into the partially molten mantle under the less dense plate. The islands are composed of the extrusive igneous rocks basalt and andesite. The basalt originates most likely from the plastic mantle. The andesite originates most likely from the melting of parts of the descending plate and sediments that had accumulated on its surface. Most of the basalt that forms island arcs comes from the A) crust B) rigid mantle C) asthenosphere D) stiffer mantle

Base your answers to questions 117 through 119 on the passage and cross section below and on your knowledge of Earth science. The cross section represents one theory of the movement of rock materials in Earth's dynamic interior. Some mantle plumes that are slowly rising from the boundary between Earth's outer core and stiffer mantle are indicated. Hot Spots and Mantle Plumes Research of mantle hot spots indicates that mantle plumes form in a variety of sizes and shapes. These mantle plumes range in diameter from several hundred kilometers to 1000 kilometers. Some plumes rise as blobs rather than in a continuous streak; however, most plumes are long, slender columns of hot rock slowly rising in Earth's stiffer mantle. One theory is that most plumes form at the boundary between the outer core and the stiffer mantle. They may reach Earth's surface in the center of plates or at plate boundaries, producing volcanoes or large domes. 117. The basaltic rock that forms volcanic mountains where mantle plumes reach Earth's surface is usually composed of A) fine-grained, dark-colored felsic minerals B) fine-grained, dark-colored mafic minerals C) coarse-grained, light-colored felsic minerals D) coarse-grained, light-colored mafic minerals 118. At which depth below Earth's surface is the boundary between Earth's outer core and stiffer mantle located? A) 700 km B) 2000 km C) 2900 km D) 5100 km 119. Compared to the surrounding material, mantle plumes rise toward Earth's surface from the core-mantle boundary because they are A) cooler and less dense B) cooler and more dense C) hotter and less dense D) hotter and more dense

120. Earth s inner core is inferred to be solid based on the analysis of A) seismic waves B) crustal rocks C) radioactive decay rates D) magnetic pole reversals EARTH'S INTERIOR MEGA PACKET MC

121. Base your answer to the following question on "cross section below, which shows an underwater mountain range in the Atlantic Ocean. The oceanic bedrock is composed mainly of basalt. Points X and Y are locations in the bedrock that have been diverging at the same rate. The movement of the North American Plate and Eurasian Plate is shown by the two arrows. "

A) EARTH'S INTERIOR MEGA PACKET MC Which cross section best represents the relative locations of Earth's asthenosphere, rigid mantle, and stiffer mantle? (The cross sections are not drawn to scale.) B) C) D) 122. Scientists have inferred the structure of Earth s interior mainly by analyzing A) the Moon s interior B) the Moon s composition C) Earth s surface features D) Earth s seismic data 123. Earth s outer core and inner core are both inferred to be A) liquid B) solid C) composed of a high percentage of iron D) under the same pressure

124. Andrija Mohorovicic discovered the interface between the crust and the mantle that is now named for him. His discovery of the Moho was based on analysis of A) landscape boundaries B) continental coastlines C) erosional surfaces D) seismic waves 125. Most inferences about the characteristics of Earth s mantle and core are based on EARTH'S INTERIOR MEGA PACKET MC A) the behavior of seismic waves in Earth s interior B) well drillings from Earth s mantle and core C) chemical changes in exposed and weathered metamorphic rocks D) comparisons between Moon rocks and Earth rocks 126. Geologists have used information about the composition of meteorites to make inferences about Earth s A) core properties B) atmospheric structure C) asthenosphere location D) continental-crust thickness

Base your answers to questions 127 through 131 on the diagram below which represents Earth's interior zones. 129. Which graph best represents the relationship between depth below Earth's surface and density? A) B) 127. Scientists have classified Earth's interior into the zones shown based primarily on evidence gained by studying A) deep drill cores B) volcanic eruptions C) gravity measurements D) earthquake seismic waves 128. The thinnest section of Earth's crust is found beneath A) oceans B) desert regions C) coastal plains D) mountain regions C) D) 130. In which layer of Earth's interior is the inferred temperature 6,000 C? A) crust B) mantle C) outer core D) inner core 131. The composition of Earth's core is thought to be the same as the composition of many A) meteorites B) volcanic ashes C) granites D) basalts

132. The photograph below shows a large crater located in the southwestern United States. Some fragments taken from the site have a nickel-iron composition. This evidence indicates that the crater probably was formed by A) the impact of a meteorite from space B) the collapse of a cavern roof C) an eruption of a volcano D) an underwater explosion of steam 133. The Earth's core is believed to be composed primarily of A) oxygen and silicon B) aluminum and silicon C) iron and nickel D) carbon and iron 134. Many scientists infer the composition of the Earth's core to be similar to the composition of A) metallic meteorites B) Moon rocks C) the mantle D) the oceanic crust 135. Theories about the composition of the Earth's core are supported by meteorites that are composed primarily of A) oxygen and silicon B) aluminum and iron C) aluminum and oxygen D) iron and nickel

Answer Key EARTHS INTERIOR MEGA PACKET MC 1. D 37. C 73. A 109. C 2. A 38. D 74. C 110. D 3. B 39. D 75. A 111. A 4. B 40. A 76. A 112. A 5. B 41. B 77. A 113. A 6. B 42. D 78. B 114. D 7. B 43. B 79. A 115. A 8. D 44. C 80. B 116. C 9. C 45. D 81. C 117. B 10. C 46. D 82. A 118. C 11. B 47. B 83. C 119. C 12. B 48. B 84. D 120. A 13. D 49. A 85. C 121. A 14. A 50. D 86. C 122. D 15. D 51. A 87. C 123. C 16. A 52. A 88. C 124. D 17. A 53. A 89. B 125. A 18. A 54. B 90. B 126. A 19. B 55. B 91. C 127. D 20. A 56. A 92. C 128. A 21. A 57. A 93. B 129. D 22. C 58. A 94. D 130. C 23. C 59. C 95. C 131. A 24. C 60. A 96. C 132. A 25. D 61. B 97. D 133. C 26. B 62. C 98. A 134. A 27. C 63. A 99. B 135. D 28. C 64. A 100. B 29. A 65. C 101. B 30. B 66. C 102. D 31. C 67. B 103. D 32. D 68. B 104. C 33. C 69. C 105. C 34. D 70. A 106. C 35. C 71. B 107. C 36. D 72. C 108. D