Earth 107: Volcan and Earthquakes Question Bank PDF

Earth 107: Volcanos and Earthquakes Question Bank The correct answer is in bold. 1. Which of the following is correct? (A) Continental crustal thickness increases with elevation. (B) Continental crust is much thicker than oceanic crus...

Earth 107: Volcanos and Earthquakes Question Bank The correct answer is in bold. 1. Which of the following is correct? (A) Continental crustal thickness increases with elevation. (B) Continental crust is much thicker than oceanic crust. (C) Lithosphere is the same as the crust. (D) All of the above (E) A and B but not C. 2. Which of the following is correct? (A) Crust at Michigan is thinner than that at Tibet (~5 km elevation). (B) Crust at Michigan is thinner than that of the Pacific Ocean. (C) Crust at Tibet is thinner than that of the Indian Ocean. (D) A and C but not B. (E) None of the above. 3. The layers of the Earth from the inside out are: (A) the core, mantle, and crust (B) the mantle, core, and crust (C) the mantle, crust, and core (D) the crust, core, and mantle 4. Among the following, which killed the most people in the last 100 years? (A) Earthquakes (B) Hurricanes (C) Landslides (D) Volcanic eruptions (E) Wars 5. In plate tectonics, a major plate is (A) a continent. (B) a continent-size surface block (oceanic and/or continental) of the Earth. (C) a flat piece of rock that can be used as a weapon. (D) a flat piece of rock that moves up and down. (E) a mountain range. 6. The typical thickness of a plate (in plate tectonics) is: (A) 1 km. (B) 10 km. (C) 100 km. (D) 1000 km. 7. The boundaries between between Earth’s crust, mantle and core are based on: (A) seismic wave velocities. (B) temperature. (C) pressure. (D) all of the above. 8. The differences of Earth's interior layers of crust, mantle, and core include  (A) chemical composition. (B) mineral phases. (C) liquid or solid state. (D) all of the above. 9. The boundary between Earth’s lithosphere and asthenosphere is based on: (A) seismic wave velocities. (B) temperature. (C) pressure. (D) all of the above. 10. The division of Earth's interior into lithosphere and asthenosphere is based on: (A) chemical composition. (B) mineral phases. (C) mechanical properties, especially whether the layer may flow.. (D) all of the above. 11. Which of the following are plate boundaries? (A) Mid-ocean ridges. (B) Collision zones of two continents. (C) Coastlines. (D) All of the above. (E) A and B but not C. 12. Which of the following are plate boundaries? (A) Mid-ocean ridges. (B) Subduction zones. (C) Transform faults. (D) All of the above. (E) A and B but not C. 13. At a mid-ocean ridge, (A) oceanic plates are moving apart. (B) crustal age is young. (C) ocean water depth is shallow compared to ocean basins. (D) all of the above. (E) A and C but not B. 14. There are many earthquakes at (A) mid-ocean ridges. (B) subduction zones. (C) transform faults. (D) all of the above. (E) A and B but not C. 15. There are abundant volcanic activities at: (A) mid-ocean ridges. (B) subduction zones. (C) transform faults. (D) all of the above. (E) A and B but not C. 16. We infer that continents (or more accurately, plates) are moving based on (A) good match of continental coastlines on the two sides of the Atlantic. (B) magnetic anomalies on the ocean floor. (C) age of oceanic crust. (D) direct measurement of distance between continents. (E) all of the above. 17. In plate tectonics, how many major plates are there? (A) Less than 3. (B) 7 to 15. (C) About 100. (D) About 1000. (E) There are many thousands. 18. A mid-ocean ridge is (A) a divergent plate boundary. (B) a convergent plate boundary. (C) a transform fault. (D) all of the above (E) none of the above 19. A convergent plate boundary may include: (A) continental-continental collision. (B) an oceanic plate subducting under another oceanic plate. (C) an oceanic plate subducting under a continental plate. (D) all of the above. (E) none of the above. 20. Which of the following is correct? (A) Earth’s magnetic polarity has changed many times in geologic history. (B) Very hot magma is not magnetic. (C) Oceanic crust show magnetic anomalies. (D) All of the above. (E) A and C but not B. 21. A mid-ocean ridge is (A) where new oceanic crust is generated. (B) always near the center line of an ocean. (C) higher than the surrounding ocean basins. (D) all of the above. (E) A and C but not B. 22. Along mid-ocean ridges, (A) there are earthquakes. (B) there are volcanic eruptions. (C) both of the above. (D) none of the above. 23. Along subduction zones, (A) there are earthquakes. (B) there are volcanic eruptions. (C) both of the above.  (D) none of the above. 24. Along transform faults, (A) there are earthquakes. (B) there are volcanic eruptions. (C) both of the above. (D) none of the above. 25. The thickness of a typical continental crust is (A) 1 to 2 km. (B) 6 to 7 km. (C) 10-15 km. (D) 35-45 km. (E) 60 to 70 km. 26. The thickness of a typical oceanic crust (not including water) is (A) 1 to 2 km. (B) 6 to 7 km. (C) 10-15 km. (D) 35-45 km. (E) 60 to 70 km. 27. The lithosphere is (A) the crust. (B) the mantle. (C) the core. (D) the asthenosphere. (E) none of the above. 28. A subduction zone is (A) a convergent plate boundary. (B) accompanied by volcanos. (C) a zone with many earthquakes. (D) all of the above. (E) B and C but not A. 29. An example of product of continent-continent collision is: (A) Tibetan Plateau in China. (B) The Andes in South America. (C) The Cascades of North America. (D) Mauna Loa of Hawaii, USA. (E) East African Rift Valley. 30. In earthquake hazard maps, mid-ocean ridges do not show up as a prominent feature because: (A) there are no earthquakes along mid-ocean ridges. (B) earthquakes along mid-ocean ridges are small. (C) almost no people live on mid-ocean ridges. (D) all of the above. (E) B and C but not A. 31. Historically, most earthquake deaths occurred in:  (A) China. (B) India. (C) Indonesia. (D) Japan. (E) the United States. 32. Most earthquakes occur: (A) along plate boundaries. (B) in the interior of plates. (C) in the lower mantle. (D) in oceanic basins. 33. Historically, most earthquake deaths occur during: (A) mid-ocean ridge earthquakes. (B) intraplate earthquakes. (C) subduction zone earthquakes. (D) transform fault earthquakes. 34. China claims the unenviable title of most earthquake deaths in the 20th century. Most of these deadly earthquakes occur (A) along mid-ocean ridges. (B) along transform faults. (C) along subduction zones. (D) in the interior of a plate. 35. One explanation for numerous deadly intraplate earthquakes in China and India is: (A) that India and China are along plate boundaries. (B) pushing of Indian subcontinent into mainland Asia. (C) subduction of Indian ocean under India and China. (D) a transform fault between India and China. 36. Which of the following is a subduction zone earthquake? (A) 2004 Sumatra earthquake (and Indian Ocean tsunami). (B) 1976 Tangshan earthquake. (C) 1906 San Francisco earthquake. (D) All of the above. (E) A and C but not B. 37. Which of the following is a transform fault earthquake? (A) 1923 Tokyo earthquake. (B) 1976 Tangshan earthquake. (C) 1906 San Francisco earthquake. (D) All of the above. (E) A and C but not B. 38. Which of the following is an intraplate earthquake? (A) 1923 Tokyo earthquake. (B) 1976 Tangshan earthquake. (C) 1906 San Francisco earthquake. (D) All of the above. (E) A and C but not B. 39. In the United States, devastating earthquakes may occur in  (A) Alaska. (B) Hawaii. (C) Western US. (D) New Madrid zone. (E) all of the above. 40. In the 48 contiguous states of USA, devastating earthquakes occur (A) only at the plate boundaries. (B) only in the western United States. (C) in a couple of linear belts and a few circular regions. (D) everywhere in the US. 41. In the United States, there are earthquakes in (A) California. (B) Alaska. (C) Hawaii. (D) all of the above. (E) A and C but not B. 42. In the United States, there is significant earthquake hazard in: (A) the west coast. (B) Michigan. (C) New Madrid zone. (D) all of the above. (E) A and C but not B. 43. There are earthquakes along the west coast of the US because (A) there is a transform fault. (B) there is a subduction zone. (C) both of the above. (D) none of the above. 44. Along the west coast of North America, there are the following type(s) of plate boundaries: (A) Divergent plate boundary. (B) Convergent plate boundary. (C) Transform fault. (D) All of the above. (E) A and C but not B. 45. Name an intraplate earthquake zone in the US: (A) California earthquake zone. (B) New Madrid earthquake zone. (C) Aleutian earthquake zone. 46. Which of the following is incorrect: (A) San Andreas Fault is a transform fault. (B) Mid-Atlantic Ridge is a mid-ocean ridge. (C) All of California belongs to the North American Plate. (D) New Madrid earthquake zone in an intraplate earthquake zone. 47. Which of the following is incorrect? (A) P wave is a body wave. (B) S wave is a body wave. (C) Love wave is a surface wave. (D) Rayleigh wave is a surface wave. (E) Body waves travel slower than surface waves. 48. In an earthquake, which of the following waves arrives first? (A) P wave. (B) S wave. (C) Love wave. (D) Rayleigh wave. 49. Which of the following waves cannot travel in liquid? (A) P and S waves. (B) S and Love waves. (C) S and Rayleigh waves. (D) Love and Rayleigh waves. 50. In which of the following waves is the direction of particle motion perpendicular to the direction of wave propagation? (A) P and S waves. (B) S and Love waves. (C) S and Rayleigh waves. (D) Love and Rayleigh waves. 51. In an earthquake, which of the following waves typically causes the least ground shaking? (A) P wave. (B) S wave. (C) Love wave. (D) Rayleigh wave. 52. To find the epicenter of an earthquake from seismic stations, you need at least (A) one seismic station. (B) two seismic stations. (C) three seismic stations. (D) four seismic stations. 53. On the Richter scale, when the magnitude differs by one, what is the difference in terms of energy? (A) The energy differs by roughly a factor of 3. (B) The energy differs by roughly a factor of 30. (C) The energy differs by roughly a factor of 300. (D) The energy differs by roughly a factor of 3,000. 54. Differences between earthquake magnitude and intensity include: (A) magnitude is a measure of the whole earthquake, and intensity is a measure of local destruction. (B) there is only one magnitude for an earthquake, whereas the intensity varies from place to place. (C) magnitude can be predicted but intensity cannot be predicted. (D) all of the above. (E) A and B but not C. 55. Which of the following is incorrect? (A) There are many more smaller earthquakes than larger ones. (B) A larger earthquake releases more energy than a smaller earthquake.  (C) Larger earthquakes (magnitude 7 or large) kill more people than smaller earthquakes. (D) Total energy released by a smaller number of larger earthquakes is smaller than that by a larger number of smaller earthquakes. 56. Which of the following is correct? (A) Earthquakes can be forecasted at present. (B) Earthquakes cannot be forecasted at present. 57. A seismograph that can measure ground motion contains (A) A pen that is fixed to a drum and a drum that is partially immersed in liquid. (B) A pen that is attached to a pendulum and a drum that is fixed to the ground. (C) A pendulum that is fixed to a drum. (D) A drum that carries both a pen and recording paper. 58. In earthquake risk assessment, which of the following is (are) assessed? (A) Past earthquake activities. (B) Types of ground. (C) Known active faults. (D) All of the above. (E) A and C but not B. 59. What kind of ground can amplify shaking amplitude during an earthquake? (A) Bed rock. (B) Loose soil. (C) None of the above. All grounds experience similar amount of shaking. 60. Which of the following help(s) to sustain an earthquake? (A) A building on solid bedrock. (B) A building on a high mountain. (C) A building near the beach. (D) All of the above. (E) A and B but not C. 61. Which of the following is correct? (A) For a normal fault, the lower block moves down. (B) For a reverse fault, the upper block moves down. (C) For a right-lateral strike-slip fault, when you stand on one side and look at the other side, the other side moves to the right. (D) All of the above. (E) None of the above. 62. If the upper block moves down, the fault is (A) a normal fault. (B) a reverse fault. (C) a left-lateral strike-slip fault. (D) a right-lateral strike-slip fault. (E) none of the above. 63. If you stand on one block, the opposite block moves to the left. The fault is (A) a normal fault. (B) a reverse fault. (C) a left-lateral strike-slip fault. (D) a right-lateral strike-slip fault.  (E) none of the above. 64. The causes of earthquakes include: (A) meteorite impact. (B) sudden earth movement along a fault. (C) volcanic activities. (D) all of the above, (E) B and C but not A. 65. Liquefaction of soil can be induced by: (A) earthquakes. (B) repeatedly stepping onto beach sand. (C) lowering the temperature. (D) all of the above. (E) A and B but not C. 66. Resonance is achieved when (A) the vibrational frequency of an earthquake matches the characteristic vibrational frequency of a building. (B) a building is near the epicenter of the earthquake. (C) S wave and P wave frequencies are the same. (D) all of the above. (E) A and B but not C. 67. Which of the following is correct? (A) There is a P-wave shadow for an earthquake. (B) There is an S-wave shadow for an earthquake. (C) Both of the above. (D) There are no shadows. 68. What is a P-wave shadow for an earthquake? (A) A region of the Earth where direct P-wave signal from the earthquake cannot reach. (B) When there is sunshine, P wave casts a shadow the same way as a person does. (C) The opposite side of the Earth of the earthquake. (D) All of the above. (E) None of the above. 69. The global distribution of earthquakes and the global earthquake hazard map are not identical because: (A) earthquake hazard map also considers whether there are people. (B) earthquake hazard map also considers the local ground condition. (C) earthquake hazard map also includes earthquakes related to magma motion. (D) all of the above. (E) A and B but not C. 70. Which of the following is incorrect? (A) There is no S wave in the outer core. (B) P wave can pass through both outer and inner core. (C) In general, P wave velocity increases with depth in Earth’s mantle. (D) In general, P wave velocity increases from the surface to the center of the Earth. (E) We roughly know the S wave velocity in the inner core. 71. What is the difference between the epicenter and hypocenter (also called focus) of an earthquake? (A) The hypocenter is the actual location of an earthquake inside the Earth, and the epicenter is the projection of the hypocenter to Earth’s surface.  (B) The epicenter is the actual location of an earthquake inside the Earth, and the hypocenter is the projection of the hypocenter to Earth’s surface. (C) The epicenter is deeper than the hypocenter. 72. Richter magnitude is a measure of (A) the size of an earthquake. (B) local ground motion of an earthquake. (C) the depth of an earthquake. (D) all of the above. (E) A and B but not C. 73. Mercalli intensity scale measures (A) the total energy released by an earthquake. (B) local destruction and how it is felt by people. (C) the depth of an earthquake. (D) all of the above. (E) A and B but not C. 74. During an earthquake, (A) All types of ground experience similar shaking. (B) There is more shaking near the epicenter, regardless of the type of ground. (C) There is usually more shaking near the epicenter but the type of ground also plays a role. (D) The amount of shaking is completely controlled by the types of ground, regardless of the distance from the epicenter. 75. The surface temperature of the Earth is roughly (A) 0 K. (B) 30 K (C) 300 K. (D) 3000 K. (E) 5000 K. 76. The core temperature of the Earth is roughly (A) 0 K. (B) 30 K (C) 300 K. (D) 3000 K. (E) 5000 K. 77. The depth to the core-mantle boundary is about: (A) 35 km. (B) 400 km. (C) 660 km. (D) 2890 km. (E) 5200 km. 78. The Earth’s core is mostly made of (A) hot water. (B) silicate rocks. (C) Fe metal. (D) Diamond. 79. You are on an ocean beach. Which of the following indicate the possibility that a tsunami is coming your way: (A) A 20-m high water wave is coming toward the beach.  (B) Ocean water suddenly and rapidly recedes from the beach, exposing marine lives. (C) Ocean water suddenly becomes frothy. (D) All of the above. (E) A and C but not B. 80. Tsunami is due to: (A) differential attraction of water by Moon. (B) a sudden displacement of a large body of water. (C) tide. (D) all of the above. (E) none of the above. 81. Tsunami travels at a speed of (gh)1/2 where g is acceleration due to Earth’s gravity and h is ocean water depth. If ocean water depth is 5500 m, what is the traveling speed of tsunami? (A) 55 m/s. (B) 132 m/s. (C) 232 m/s. (D) 323 m/s. (E) 800 m/s. 82. Suppose average velocity of tsunami is 200 m/s. A large earthquake occurred in Japan, 8000 km away from San Francisco. How long would it take for the tsunami to arrive at San Francisco? (A) about 10 s. (B) about 40 s. (C) about 4 hr. (D) about 11 hrs. (E) about 100 hrs. 83. Tsunamis can be induced by: (A) earthquakes. (B) volcanic eruptions. (C) submarine landslides. (D) all of the above. (E) A and B but not C. 84. In addition to understanding earthquakes, seismology has also contributed to: (A) understanding the structure of the Earth. (B) national defense in terms of detecting nuclear explosions and verification of nuclear test treaties. (C) the forecast of volcanic eruptions. (D) all of the above. (E) A and B but not C. 85. Seismologists can distinguish nuclear explosions and earthquakes from (A) the arrival times of various waves. (B) the ratio of P wave amplitude to S wave amplitude. (C) the amplitude of surface waves. (D) all of the above. (E) A and B but not C. 86. Subduction slab can be imaged by seismologists because (A) it has a greater seismic velocity compared to the ambient rocks. (B) it is hotter than the ambient rocks. (C) it is more fluid than the ambient rocks.  (D) all of the above. (E) A and B but not C. 87. Historically, most volcanic eruption deaths occurred in: (A) China. (B) India. (C) Indonesia. (D) Japan. (E) the United States. 88. Historically, the most devastating volcanic eruptions occurred: (A) along mid-ocean ridge eruption. (B) along subduction zones. (C) in the interior of plates. (D) all of the above. (E) A and B but not C. 89. Indonesia claims the unenviable title of most volcanic eruption deaths. Most of these volcanos are (A) along mid-ocean ridges. (B) along subduction zones. (C) along transform faults. (D) in the interior of a plate. 90. Volcanic activities at mid-ocean ridges are usually (A) basaltic. (B) non-explosive. (C) small in volume. (D) all of the above. (E) A and B but not C. 91. Volcanic activities at mid-ocean ridges are not discussed much as hazard because: (A) there is no volcanism along mid-ocean ridges. (B) they are small in volume. (C) they are usually underwater and non-explosive. (D) all of the above. (E) B and C but not A. 92. Which of the following volcanic features is the largest? (A) Stratovolcanos. (B) Shield volcanos. (C) Flood basalt provinces. (D) Cinder cones. (E) Tuff rings. 93. Which of the following volcanic features is the largest? (A) Stratovolcanos. (B) Shield volcanos. (C) Lava domes. (D) Cinder cones. (E) Lava flows. 94. Which of the following volcanic features is the largest? (A) Stratovolcanos. (B) Lava domes.  (C) Cinder cones. (D) Tuff rings. (E) Volcanic crater 95. What are the differences between a volcanic crater and a caldera? (A) They are different in size. (B) They are different in mechanisms of formation. (C) They are different in terms of magma composition. (D) All of the above. (E) A and B but not C. 96. Which of the following volcanic features is usually the largest? (A) A volcanic crater. (B) A caldera. (C) A lava dome. (D) A cinder cone. 97. Which of the following volcanic features is associated with the most explosive eruptions? (A) Stratovolcanos. (B) Shield volcanos. (C) Flood basalt provinces. (D) Cinder cones. (E) Tuff rings. 98. Which of the following volcanic features is more likely associated with explosive eruptions? (A) A lava flow. (B) A caldera. (C) A lava dome. (D) A cinder cone. (E) A shield volcano. 99. A shield volcano may include the following features: (A) Cinder cones. (B) Lava flows. (C) Stratovolcanos. (D) All of the above. (E) A and B but not C. 100. A shield volcano may include the following features: (A) Cinder cones. (B) Lava flows. (C) Lava lakes. (D) All of the above. (E) A and B but not C. 101. It is possible to investigate Hawaiian-type eruption at a short distance because: (A) Hawaii is near the equator and the weather is good. (B) Hawaiian type magma is not hot. (C) Hawaiian volcanos are small. (D) all of the above. (E) none of the above. 102. The following types of eruptions are explosive:  (A) Plinian eruptions. (B) pyroclastic flows. (C) lava flows. (D) all of the above. (E) A and B but not C. 103. The following types of eruptions are non-explosive eruptions: (A) Lava dome eruptions. (B) Lava flows. (C) A 40-km high eruption column. (D) All of the above. (E) A and B but not C. 104. Compared to a shield volcano, a stratovolcano is (A) smaller. (B) steeper. (C) more explosive. (D) all of the above. (E) A and B but not C. 105. Which of the following statements is correct: (A) The biggest volcano in the solar system is on the Earth. (B) The Earth is volcanically more active than all other planets and satellites. (C) The Earth has the highest mountains of the solar system. (D) All of the above. (E) None of the above. 106. The following features indicate an oceanic hotspot: (A) A roughly linear string of ocean islands. (B) One end of the linear array of islands is volcanically active. (C) The age of the islands increases as distance from the volcanically active island increases. (D) All of the above. (E). A and B but not C. 107. A caldera is (A) roughly circular. (B) always associated with a caldera lake. (C) usually larger than 100 km across. (D) all of the above. (E) A and B but not C. 108. The typical volume of a flood basalt province is: (A) 100 km3. (B) 104 km3. (C) 106 km3. (D) 108 km3. (E) 1010 km3. 109. The critical difference(s) leading to plinean eruption vs. pyroclastic flow includes: (A) eruption temperature. (B) density. (C) viscosity. (D) all of the above.  (E) none of the above. 110. The following factors tend to make an explosive eruption: (A) high concentration of gas. (B) high viscosity. (C) high temperature of magma. (D) all of the above. (E) A and B but not C. 111. What is a typical temperature range of terrestrial silicate magma? (A) 100°C. (B) 400°C. (C) 1000°C. (D) 2000°C. (E) 5000°C. 112. The oceanic crust composition is: (A) peridotitic. (B) basaltic. (C) andesitic. (D) dacitic. (E) rhyolitic. 113. Among the eruptions with the following VEI, which is the largest? (A) VEI = 1. (B) VEI = 3. (C) VEI = 5. (D) VEI = 7. (E) VEI = 8. 114. When VEI increases by 1, the eruption volume: (A) doubles. (B) quadruples. (C) increases by a factor of 10. (D) increases by a factor of 30. (E) increases by a factor of 100. 115. VEI = log(V)+5. The 1991 eruption of Pinatubo erupted 5 km3 of tephra. What is its VEI? (A) 3.7. (B) 4.7. (C) 5.7. (D) 6.7. (E) 7.7. 116. A shield volcano is produced by: (A) plinean eruptions. (B) pyroclastic flows. (C) explosive eruptions. (D) nonexplosive eruptions. (E) none of the above. 117. For explosive eruptions, which of the following statements is correct: (A) Large eruptions are rare, but they contribute more to the erupted mass.  (B) Larger eruptions are rare. Hence smaller eruptions contribute more to the erupted mass. (C) Large eruptions are more often than smaller eruptions. (D) Large eruptions are concentrated in the western US. 118. Rocks can be melted by: (A) reducing the pressure of mantle rocks (decompressional melting). (B) adding water to hot mantle rocks. (C) adding heat to (increasing the temperature of) mantle or crustal rocks. (D) all of the above. (E) B and C but not A. 119. Magmas can be produced by: (A) reducing the pressure of mantle rocks (decompressional melting). (B) adding water to hot mantle rocks. (C) adding heat to (increasing the temperature of) mantle or crustal rocks. (D) all of the above. (E) none of the above is needed. There is always a layer of magma inside the earth. 120. Snow can be melted by: (A) reducing the pressure of snow. (B) adding salt to snow. (C) adding heat to (increasing the temperature of) snow. (D) all of the above. (E) B and C but not A. 121. The most common (voluminous) magma production is by: (A) reducing the pressure of mantle rocks (decompressional melting). (B) adding water to hot mantle rocks. (C) adding heat to (increasing the temperature of) mantle or crustal rocks. (D) none of the above. 122. Magma generation at subduction zones is mostly due to: (A) reducing the pressure of mantle rocks (decompressional melting). (B) adding water to hot mantle rocks. (C) adding heat to (increasing the temperature of) mantle or crustal rocks. (D) all of the above. (E) B and C but not A. 123. Which of the following systems may produce eruptions: (A) Water and magma. (B) Carbon dioxide and water. (C) Metamorphic rock. (D) All of the above. (E) A and B but not C. 124. An explosive volcanic eruption begins when: (A) magma temperature is greater than 1000°C. (B) pressure is greater than 1000 atmospheres. (C) temperature is low enough. (D) pressure is low enough so that gas is oversaturated and bubbles form. 125. An explosive volcanic eruption requires: (A) at least two components, one gas and one liquid.  (B) formation of the gas phase. (C) fragmentation of magma (D) all of the above. (E) A and C but not B. 126. For a large explosive eruption, the exit eruption velocity is close to: (A) sound speed of the gas-magma two-phase mixture. (B) sound speed of air. (C) speed of light. (D) speed of a car. (E) speed of an airplane. 127. The formula for exit velocity of a large explosive eruption is u = (FRT)1/2. Using SI units, the gas constant is 461.5 J·K-1·kg-1, the mass fraction of the gas phase is 0.03, and the temperature is 1100 K. The exit velocity is: (A) 12 m/s. (B) 123 m/s. (C) 1234 m/s. (D) 12345 m/s. 128. According to one theory of magma fragmentation, a slowly growing dome may suddenly collapse into a killing pyroclastic flow if (A) initial total water concentration in magma is > 1.0 wt%. (B) initial total water concentration in magma is < 0.5 wt%. (C) initial temperature is greater than 1000°C. (D) magma composition is basaltic. 129. The effect of volcanic eruption on climate include: (A) cooling. (B) warming. (C) both short-term cooling and long-term warming. (D) no cooling nor warming. 130. Volcanos and volcanic eruptions have contributed the following: (A) Atmosphere. (B) Oceans. (C) Land. (D) All of the above. (E) A and C but not B. 131. The eruption volume of the largest known explosive eruptions is of the order: (A) 3 km3. (B) 30 km3. (C) 300 km3. (D) 3000 km3. (E) 30000 km3. 132. In recorded human history, gigantic explosive eruptions with eruption volume of over 1000 km3 have been known to have occurred: (A) 0 times. (B) 1 time.  (C) 3 times. (D) 7 times. (E) 20 times. 133. The following volcanic field(s) in the US has (have) produced explosive eruptions of ≥ 1000 km3: (A) Long Valley Caldera. (B) Yellowstone. (C) Mount Rainier. (D) All of the above. (E) A and B but not C. 134. Observation(s) used to forecast a major volcanic eruptions includes (include): (A) degassing and small eruptions. (B) seismic activities. (C) ground swelling. (D) all of the above. (E) A and B but not C. 135. For lake eruptions to occur, (A) the lake should have a gas source. (B) the lake should be deep. (C) the lake should be in equatorial region. (D) all of the above. (E) A and B but not C. 136. Lake eruptions are powered by: (A) dissolved air in water. (B) dissolved CO2 in water. (C) fish in water. (D) a turbo pump in the lake. 137. Scientists and engineers are working to prevent future lake eruptions by: (A) drying the lake. (B) adding water to the lake to make it deeper. (C) pumping deep water to the surface of the same lake to degas it. (D) building a big wall around the lake. 138. Which of the following lake(s) may erupt (similar to Lake Nyos)? (A) Lake Michigan, USA. (B) Crater Lake, Oregon, USA. (C) Lake Tahoe, California, USA. (D) All of the above. (E) None of the above. 139. Which of the following melts has the highest viscosity? (A) Basaltic melt. (B) Andesitic melt. (C) Dacitic melt. (D) Rhyolitic melt. 140. Which of the following melts has the highest melting temperature? (A) Basaltic melt. (B) Andesitic melt.  (C) Dacitic melt. (D) Rhyolitic melt. 141. “The Pacific Ring of Fire” means: (A) Most wild fires occur along the Pacific coast. (B) The Olympic torch is passed circling the Pacific. (C) There are many volcanos along the Pacific coast. (D) All of the above. (E) None of the above. 142. Volcanic activities can induce (A) earthquakes. (B) tsunami. (C) mudslides. (D) all of the above. (E) B and C but not A. 143. Earthquakes can induce: (A) volcanic eruptions. (B) tsunami. (C) landslides. (D) all of the above. (E) B and C but not A. 144. Which of the following is correct? (A) Large earthquakes are more energetic than large volcanic eruptions and kill more people. (B) Large earthquakes are less energetic than large volcanic eruptions but kill more people. (C) Large earthquakes are more energetic than large volcanic eruptions but kill less people. (D) Large earthquakes are less energetic than large volcanic eruptions and kill less people. 145. Which of the following is correct? (A) Explosive volcanic eruptions require sufficient water content in the magma. (B) High viscosity leads to explosive eruptions. (C) Large magma volume leads to explosive eruptions. (D) All of the above. (E) A and B but not C. 146. For a known major fault, (A) If there are frequent small earthquakes along the fault, it is relatively safe to live nearby. (B) If there have been no earthquakes along the fault for many years, it is relatively safe to live nearby. 147. For a known major volcano, (A) If it has been erupting for some time recently, it is relatively safe to live nearby. (B) If it has not been eruption for a long time (such as 10,000 years), it is relatively safe to live nearby. 148. There are the following natural hazard(s) in California: (A) Earthquakes. (B) Volcanic eruptions. (C) Lake eruptions. (D) All of the above. (E) A and B but not C. 149. There are the following natural hazard(s) in Michigan: (A) Earthquakes. (B) Volcanic eruptions. (C) Lake eruptions. (D) A and B but not C. (E) None of the above. 150. There are the following natural hazard(s) in Yellowstone National Park: (A) Hot spring eruptions. (B) Volcanic eruptions. (C) Lake eruptions. (D) All of the above. (E) A and B but not C. 151. Which one of the following volcanic fields has erupted more than 1000 km3 in geologic history? (A) Yellowstone. (B) Mount St. Helens, Washington. (C) Mount Shasta, California. (D) Mount Rainier, Washington. 152. What is the minimum requirement for gas-driven eruptions? (A) There must be a lake. (B) There must be hot magma. (C) There must be a gas component initially dissolved in a liquid. (D) There must be a mountain. 153. Which of the following is correct? (A) It is possible to forecast volcanic eruptions and earthquakes. (B) It is possible to forecast volcanic eruptions, but not earthquakes. (C) It is possible to forecast earthquakes, but not volcanic eruptions. (D) It is not possible to forecast volcanic eruptions, nor earthquakes. 154. Earthquakes can destroy through the following means: (A) Ground shaking causing structure collapse. (B) Tsunami. (C) Landslide and liquefaction. (D) All of the above. (E) A and C but not B. 155. Volcanic eruptions can destroy through the following means: (A) Pyroclastic flow. (B) Tsunami. (C) Lahar. (D) All of the above. (E) A and C but not B. 156. Most land volcanos occur at: (A) mid-ocean ridges. (B) subduction zones. (C) transform faults.  (D) all of the above. (E) A and B but not C. 157. Which of the following is incorrect? (A) The Earth is a big magnet. (B) A significant part of the interior of the Earth is liquid. (C) The center of the Earth is solid. (D) Subducted slab goes to the inner core. 158. Which of the following is correct? (A) Continental crust is thicker underneath a high mountain. (B) Oceanic crust is much thinner than continental crust. (C) Ocean islands are usually volcanic. (D) All of the above. (E) A and B but not C. 159. The 26 December 2004 Sumatra earthquake occurred (A) at a subduction zone. (B) at a mid-ocean ridge. (C) at a transform fault. (D) in the interior of a plate. 160. Almost 300,000 people died of the 26 December 2004 Sumatra earthquake. Most of the deaths are caused by (A) collapse of buildings due to ground shaking. (B) tsunami. (C) landslide. (D) fires. (E) liquefaction. 161. It is possible to forecast the following natural disaster(s) to provide warning to residents: (A) Earthquakes. (B) Volcanic eruptions. (C) Tsunami. (D) All of the above. (E) B and C but not A. 162. Predictions of plate motions include: (A) Los Angeles will move northward. (B) Mediterranean Sea will disappear. (C) New York and London will move apart. (D) all of the above. (E) A and B but not C. 163. The following observation shows that the outer core is liquid: (A) Scientist drilled to the outer core and found that it is liquid. (B) The observed distribution pattern of the S-wave shadow for earthquakes. (C) The observed distribution pattern of the P-wave shadow for earthquakes. (D) All of the above. 164. The chart for obtaining Richter magnitude is reproduced below. If the time interval between S and P arrivals is 40 s, and the amplitude of the vibration on the seismogram is 50 mm, the Richter magnitude of the earthquake is about: (A) 7. (B) 6. (C) 5. (D) 4. (E) 3.