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K12 LibreTexts

7.8: Geological Activity and Volcanoes- Challenge 1

  • Page ID
    5432
  • 1. A volcano on the Hawai'i hotspot is ___; a volcano that has just moved off the hotspot is ___; a volcano that is far from the hotspot is ___.
    active; dormant; extinct
    2. Volcanoes are located around ___ and ___ plate boundaries.
    convergent; divergent
    3. Mantle rock melts to form ___ if temperature rises, pressure decreases, or water mixes with the mantle.
    magma
    4. Lava erupts through long cracks in the ground called ___.
    fissures
    5. ___ are a chain of volcanoes in the Pacific Northwest of North America that formed on a convergent plate boundary.
    The Cascades
    6. Which of the following is/are example(s) of volcanic arcs: the Himalayas, Mount Gahinga, or the Cascades?
    The Cascades
    7. Hotspot volcanoes form when ___.
    a plate moves over a mantle plume
    8. A hotspot beneath the Big Island of Hawai'i is currently covered by the ___ volcano.
    Kilauea
    9. Eruptions of hotspots beneath continents are extremely explosive, because ___.
    a mantle plume must be massive to penetrate continental crust
    10. Magma viscosity is related to magma composition: the higher the silica content, the ___ the viscosity.
    higher
    11. ___ is a fluid's resistance to flow.
    viscosity
    12. ___ lava is low in silica, less viscous, and erupts effusively.
    Mafic
    13. A ___ is a volcanic mudflow made of ash and water, while a ___ is made of hot fragments of rock and ash.
    lahar; pyroclastic flow
    14. Before an explosive eruption, ___ pressure builds until it is released violently.
    gas
    15. Mt. Shasta, an active volcano, is located in ___.
    California