Types of Volcanoes
Which volcano type has gentle slopes, is made by thin, flowing lava, and includes Mauna Loa?
Shield volcano
What property describes how easily a liquid flows (important for magma and lava)?
Viscosity
What are the small pieces of pulverized rock and glass ejected during eruption called (they can form clouds)?
Ash (ash cloud)
What term describes a volcano that is not currently erupting but might again?
Dormant
What is the circular basin or depression at the summit of a volcano called?
Crater
What kind of volcano is small, steep-sided, and built from cinders and ash in a short time?
Cinder cone volcano
How does silica content affect magma viscosity — more silica makes magma _____ ?
Higher silica → higher viscosity (thicker)
What are volcanic bombs?
Large projectiles of molten rock ejected during eruptions
What term describes a volcano that is unlikely to erupt again?
Extinct
Name the molten rock while it is still beneath Earth's surface.
Magma
Which volcano type is built by alternating layers of lava, ash, and cinders and can be highly explosive?
Composite volcano (stratovolcano)
Which type of lava is very hot and flows smoothly, often forming ropy surfaces (term from Hawaii)?
Pahoehoe
Describe what a pyroclastic flow does and why it is dangerous (one or two sentences).
It moves rapidly down slopes carrying hot gas and rock fragments; it is deadly because of its speed and temperature
What term describes a volcano that has recently erupted or shows signs it might erupt soon?
Active
What is a pyroclastic flow?
A fast-moving current of hot gas and rock that moves away from a volcano
Name a volcano type formed when lava is too thick to flow far and piles up around the vent.
Lava dome (or lava plateau/dome)
Explain how temperature affects the viscosity of magma (one or two sentences).
Higher temperature → lower viscosity (flows more easily); cooler → higher viscosity
Name two hazards besides lava flows that can result from explosive volcanic eruptions.
Ash fall, pyroclastic flows, volcanic bombs, lahars (mudflows), volcanic gas emissions, tsunamis (from volcanic island collapse)
Give one example from the lesson for each activity level: active, dormant, extinct.
Active — Mount St. Helens; Dormant — Mount Fuji; Extinct — Kohala (Hawaii)
What large basin-like depression forms when the center of a volcano explodes or collapses?
Caldera
Give one real-world example (mountain or island) for each of these three types: shield, composite (stratovolcano), and cinder cone.
Shield — Mauna Loa; Composite — Mount St. Helens or Mount Fuji; Cinder cone — Paricutin
Describe how magma composition and viscosity help determine whether an eruption will be quiet or explosive.
Low-silica, low-viscosity magma → quiet, flowing eruptions; high-silica, high-viscosity magma → traps gases, builds pressure → explosive eruptions
Explain how a volcano can create secondary vents and secondary cones
Magma can find weaknesses in surrounding rock and break through in another spot (secondary vent); repeated eruptions at that spot build a secondary cone from deposited lava and cinders.
Explain how scientists might use past eruptions and geologic evidence to forecast volcanic hazards in a region
Scientists map previous eruptions, study rock layers and deposits, and monitor seismic activity and gas emissions to assess likely eruption locations and timing; this historical and geologic evidence helps forecast hazards.
List three features you might find on or near a volcano (choose any three from the lesson).
Any three: main vent, crater, secondary vent, secondary cone, volcanic bombs, ash cloud, pyroclastic flow, lava flow, magma chamber