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Volcanoes
Volcano Study Guide Part 2
Question | Answer |
---|---|
The peak (or highest point) of a mountain is also called the ______? | summit |
Where are most of the world's active volcanoes located? | The Ring of Fire, which encircles the Pacific Ocean |
What are mid-ocean ridges? | Volcanic land forms that form at divergent plate boundaries |
How is a volcanic neck formed? | It is formed when the solidified volcanic pipe remains are the most of the outside of the volcano has been eroded away. |
Lava plateaus form when? | Lava flows out of fissures (or cracks) in the Earth. |
The two most abundant gases released during a volcanic eruption are ______ and _______? | Water vapor and carbon dioxide |
The most explosive volcanoes have magma that has a ____ silica content, a ____ viscosity, and a ____ gas content. | high, high, and high |
Felsic magma contains about _____ silica. | 70% |
Magma rises because it is _____ _____ than surrounding rock. | less dense |
___ _____ are unusually hot regions of the mantle which melts rock and forces it through the crust to form a volcano. | Hot Spots |
Most volcanoes occur at __________ boundaries. | convergent |
When does a pyroclastic flow happen? | A pyroclastic flow occurs when gas, ash, tephra move down the slope of the volcano. |
When the top of a volcano collapses, it creates a larger depression around the vent called a _______. | caldera |
What is a crater? | The bowl shaped depression around the volcano's vent. |
An opening in the Earth's crust where lava escapes is the ____? | vent |
Felsic magma is ____ explosive than mafic magma. | more |
The more ______ the magma contains, the more _______ it is. | silica, viscous |
Viscosity is? | A liquid's resistance to flow. |
Tephra is? | Dust, ash, rock fragments, volcanic blocks, or volcanic bombs thrown into the air during an eruption. |