SOLVED

1) In 1980, ________ was the first Cascade Range volcano to erupt since Mt. Lassen, California, in 1915-16. A) Mt. Rainier B) Mt. Shasta C) Kilauea D) Mt. St. Helens 2) Which type of basaltic lava flow has a fairly smooth, unfragmented, ropy surface? A) aa B) pegmatitic C) pahoehoe D) scoria 3) ________ is a major dissolved volatile constituent in both magmas and volcanic gases? A) Water B) Carbon monoxide C) Hydrogen chloride D) Methane 4) Volcanic bombs originate ________. A) as laser-guided, granite blocks launched from a supersonic jet B) as blocks of volcanic rock ejected from an erupting volcanic crater C) as erupted magma blobs that partly congeal before falling to the ground D) as ash particles that join together in the eruptive plume and fall as cobble-sized objects 5) ________ magma is the most abundant type of erupted at oceanic spreading centers. A) Basaltic B) Granitic C) Andesitic D) Pegmatitic 6) The 1991 Pinatubo eruption in the Philippines caused brilliantly colored sunrises and sunsets to be seen for the next few years. What caused this phenomenon? A) The eruption added large amounts of carbon dioxide to the atmosphere. B) The eruptive cloud destroyed parts of the Earth’s protective ozone layer. C) Radioactive atoms blown into the atmosphere glowed red as they decayed. D) Sulfur dioxide and other erupted gases formed aerosols in the stratosphere. 7) The ________ ocean basin is rimmed by the most subduction zones. A) Atlantic B) Indian C) Pacific D) Arctic 8) Which was the most powerful, explosive volcanic eruption of historic time? A) Mt. Pele, Martinique, 1902 B) Vesuvius, Italy, 79 A. D. C) Tambora, Indonesia, 1815 D) Nevado del Ruiz, Colombia, 1985 9) Which of the following is associated with deep mantle hot spots? A) Vesuvius and the other volcanoes of Italy B) the volcanoes of Hawaii and Quaternary activity in Yellowstone National Park C) the very young cinder cones scattered across the southwestern United States D) Mount St. Helens and other volcanoes of the Cascade Mountains 10) Why would a plume of solid silicate rock rising slowly from deep in the mantle begin melting as it neared the base of the lithosphere? A) The rock heats up and expands at lower pressures, causing it to liquefy. B) Temperatures remain high as lowered pressures decrease melting temperatures. C) The lowered pressures cause rapid heat loss accompanied by melting. D) none of the above 1