Chapter 25.3 Flashcards
What is the boundary that marks a density change?
Discontinuity
How are discontinuities identified?
By using/studying seismic waves.
What are shadow zones?
Areas where no seismic waves are recorded.
What is another name for shadow zones?
Dead Zone
Between what degrees do shadow zones fall?
105-140 degrees
Is the outer core a solid or a liquid?
Liquid
Why is the outer core a liquid?
All the pressure.
What makes up the lithosphere?
Crust and the uppermost mantle.
What is the asthenosphere?
A plastic like-layer, which Earths plates move.
What elements make up the mantle?
Calcium, Aluminum, Iron, and Magnesium
Which elements make up the core?
Iron and Nickel
Is the measure of a fluid resistance to flow.
Viscosity
The chemical compound silica dioxide, sio2, which is a command ingredient in most magma.
Silica
Tend to be small, have heights in the hundreds of meters range , and have short eruption cycles.
Cinder cone volcanoes
Are broad, flat structures composed of layer upon layer of lava flows.
Shield volcanoes
Are large and steep-sided, often thousands of meters high and tens of kilometers across the base, and composed of layers of both lava and ash.
Composite volcanoes
What is molten or liquid, rocks stored inside Earth called?
Magma
Where is the ring of fire located?
Pacific Ocean
What are two specific locations where volcanic activity occur due to divergent valleys?
Mid-Atlantic Ocean ridge, or African Rift
Are hot spots stationary?
Yes
If magma has a high viscosity, will it contain more or less silica?
More
What is pyroclastic material?
Any solid material that comes from a volcano
What is the smallest pyroclastic material?
Volcanic ash
What is the largest pyroclastic material?
Volcanic blocks and bombs
