Volcanoes

Volcanoes form near thin parts of which layer of Earth?

• Crust

• Lithosphere

• Asthenosphere

• Outer Core

Answer explanation

The crust and solid upper mantle make up the Lithosphere. Molten rock (magma) from the Asthenosphere needs to make its way up through cracks or weak points to Earth's surface to become exposed as lava.

Repeated eruptions of lava build a volcanic structure over time depending on the type of lava, eruption frequency, etc.

Draw a shield volcano

Answer explanation

A shield volcano has a broad broad base & gently-sloping sides made of basaltic lava. Eruptions are less explosive and more frequent.

Low viscosity, low pressure, and high temperature allows for a wide base & gentle slope.

More common at hot spots, like Hawaii. The biggest volcano in the Solar System is the shield volcano Olympus Mons, on Mars.e

Which would be a synonym for VISCOSITY?

• pressure

• thickness

• villainy

• temperature

Answer explanation

Viscosity is a measurement of flow - how much will the substance move over time? High viscosity is thick, such as honey. Low viscosity is thin and runny, like your post-Taco Bell experience.

Think about how thick or thin a batter needs to be to make the best pancakes? It depends on the ratio of ingredients. Silica is an active ingredient for the viscosity of molten rock.

Lava and magma are the same material found at different places.

• True

• False

Answer explanation

Magma has a long way to travel before reaching the Earth's surface.

Materials can be added or taken away by various layers of Earth, water, organic material, gases in the atmosphere, etc.

Which type of lava has the highest temperature?

• Pillow Lava

• Aa

• Pahoehoe

Answer explanation

Pillow lava emerges underwater, mixing with water and quickly cooling.

Aa moves more slowly and starts to solidify much quicker, indicating a lower temperature and higher viscosity.

Pahoehoe flows smoothly and quickly, suggesting lower pressure, higher temperatures, and a lower viscosity.

Draw a cinder cone volcano

Answer explanation

Cinder Cone volcanoes are... you guessed it- cone-shaped.

Pyroclastic material forms a oval-shaped base around a vent, building up over time.

There are often multiple cinder cones on a larger volcanic structure. Multiple weak points can lead to numerous side vents.

Pyroclastic debris and ___ can combine to create a LAHAR

• Earth

• Fire

• Wind

• Water

• Heart

Answer explanation

With your powers combined, you too can create the deadly volcanic mudslide known as a LAHAR.

Hot pyroclastic material mixes with a water source such as an alpine lake, glacier, or snow- common at the top of many large volcanoes. It then races down the side of the volcano.

Tags

NGSS.MS-ESS2-4

Is an explosive volcano more likely to form at what tectonic boundary? 

• Subduction

• Divergent

• Hotspot

Answer explanation

The inconsistent changes underneath from subduction tectonic movement leads to inconsistent eruptions and volcanic conditions. There is more mixing from magma to lava.