Geology Quiz Answers Chapter 6

Chapter 6: ● Which of the following are typically erupted from a volcano? ○ Scalding hot ash, lava, and gases ● Which of the following is not a characteristic of an actively erupting volcano? ○ Totally covered in a fresh blanket of clean, white snow ● Which of the following is not a major controlling factor on volcanic eruption style? ○ Age of the volcano ● Which of the following materials is not produced by erupting volcanoes? ○ Sandstone ● Decreasing the pressure on a liquid that contains dissolved gases will result in ______. ○ the formation of gas bubbles ● Which of the following best describes the temperature of materials typically erupted from volcanoes? ○ Extremely hot ● Which of the following are true of felsic magmas? ○ They tend to have high viscosities. ● ● ● ● ○ High gas pressures commonly lead to highly explosive eruptions. ○ They do not allow gas bubbles to escape easily. Which of the following are characteristics of actively erupting volcanoes? ○ Billowing clouds of ash rising into the air ○ Fragments of molten rock blasting into the air ○ Glowing orange lava flowing downhill Which factor below largely controls what rock types and landforms develop from basaltic magma? ○ The characteristics and behavior of the gas in the magma Which of the following are the two main factors controlling volcanic eruption style? ○ Magma composition ○ Volatile content of the magma Which of the following accurately describe most shield volcanoes? ○ Composed of a succession of lava flows ○ Broad and gently sloping form ● Which of the following are erupted by volcanoes? ○ Lava ○ Ash ○ Pumice ● Gases more easily remain dissolved in liquids at ______ pressures. ○ High ■ High pressure outside of the liquid must be overcome by the outward pressure of the gases trying to escape the liquid. The higher the surrounding pressure, the higher the internal pressure must be in the liquids for the gas to escape. ● Match the magma type with its gas bubble behavior. ○ Felsic magma ■ Gas bubbles cannot escape easily; high pressure builds in the magma; typically, explosive eruptions; magma is high viscosity ○ Basaltic magma ■ Gas bubbles escape easily; little pressure builds in the magma; typically, nonexplosive eruptions; magma is low viscosity ● Match the volcanic feature with the hazard ○ Scoria cone ■ Falling volcanic cinders, bombs, ash, and gases ○ Lava flow ■ Burial of roads; bulldozing and crushing of houses and other structures ● Gas in basaltic magma is the major controlling factor that determines ______. ○ what landforms it will create ○ what rock types it will form ● Shield volcanoes typically have ______ slopes than composite or scoria cone volcanoes. ○ Gentler ● A volcanic eruption occurring beneath an ice sheet is likely to cause ______. ○ A hazardous flood ● Which of the following is not a hazard typically associated with scoria cones? ○ Bulldozing of houses from their foundations ● Select from below the typical components of a composite volcano. ○ Pyroclastic flows ○ Mudflow deposits ○ Lava flows ● Volcanic eruptions can produce huge floods by ______. ○ melting ice sheets ● Earthquakes at Mount St. Helens prior to the major eruption in 1980 were caused by ___. ○ magma rising in the volcano ● The typical form for a composite volcano is a ______. ○ steep-sided cone ● Steep-sided hills of viscous lava that pile up over volcanic vents are known as ______. ○ Volcanic domes ● ______ forming eruptions are the largest and most violent volcanic phenomena. ○ Caldera ● Which of the following contribute to the growth of composite volcanoes? ○ Pyroclastic flows ○ Ash column eruptions ○ Eruption of lava flows ● Which of the following represent deadly historical caldera-forming eruptions? ○ Santorini ○ Krakatau ● Which of the following were warning signs prior to the catastrophic eruption of Mount St. Helens in May 1980? ○ Formation of a bulge on its flanks ○ Earthquakes ● Volcanic domes form from the accumulation of ______ lava over a volcanic vent. ○ Viscous ● The downfall of which ancient civilization in the Mediterranean closely followed the caldera-forming eruption at Santorini? ○ Minoan ● ______ eruptions can emit more than 1,000 cubic kilometers of magma, resulting in the collapse of the overlying ground into a large crater. ○ Caldera-forming ● True or false: The volcanic hazards associated with a volcano are dependent upon the type of volcano. ○ True ■ Different types of magmas produce different types of hazards. ● Krakatau (1883) and Thera (3,500 years ago) were both disastrous _______ eruptions that blew apart islands. ○ Caldera ● Which of the following events accompanied the caldera-forming eruption at Santorini, Greece, about 3,500 years ago? ○ Huge ash column forms. ○ Pyroclastic flows occur. ○ Caldera collapse drops island beneath the sea surface. ○ Tsunami travels south and hits Crete. ● True or false: Proximity to certain types of plate boundaries is the major factor making some places more prone to volcanic hazards than others. ○ True ■ Proximity to convergent and divergent plate boundaries vastly increases the likelihood of volcanic activity in an area. ● Changes in topography, water chemistry, heat flow, and gas output all are used to help predict ______. ○ Volcanic eruptions ● Rhythmic seismic activity tends to ______ volcanic eruptions. ○ Precede and accompany ● What type of volcano is Mount Rainier? ○ Composite ● Proximity to certain types of ______ boundaries is the major factor making some places more prone to volcanic hazards than others. ○ Plate ● Mt. Rainer is located adjacent to a ______ plate boundary. ○ Convergent ● Which of the following phenomena are monitored to predict volcanic eruptions? ○ Changes in topography ○ Ground shaking ○ Heat flow changes ○ Changes in gas output ● Which of the following volcanic hazards are posed to the surrounding areas by Mount Rainier? ○ Pyroclastic flows ○ Mudflows ○ Lava flows ● Magma rising through the crust fractures rocks, producing rhythmic, repeating ______. ○ Seismic shaking ● The steep symmetrical shape of andesitic Mount Rainier indicates that it is a ______ volcano. ○ Composite ● The magma feeding Mount Rainier and the other Cascade volcanoes results from melting associated within the Cascadia _______ zone, which is an ocean-continent _____ boundary. ○ Subduction ○ Convergent