CH 25.3 & 25.4 Flashcards
What is the boundary that marks density change between layers?
discontinuity
How are discontinuities identified?
seismic waves
What are shadow zones?
areas where seismic waves aren’t recorded
What’s another name for a shadow zone?
dead zone
Between which degree ranges to shadow zones fall?
105-140 degrees from the epicenter
Is the outer core a liquid or a solid?
liquid
Is the inner core a liquid or a solid?
solid - due to pressure
What makes up the lithosphere?
crust & upper mantle
What is the asthenosphere?
weaker, plastic-like layer on which Earth’s plates move
Which elements make up the mantle?
calcium, aluminum, iron, & magnesium
Which elements make up the core?
iron & nickle
The measure of a fluid’s resistance to flow.
viscosity
The chemical compound silicon dioxide which is a common ingredient in most magma.
silica
When an eruption of high-temperature, gas-rich, mafic lava takes place, eruptive products often are ejected into the air explosively as a porous, dark colored rock called cinder.
cinder cone volcano
Broad, flat structures composed of layer upon layer of lava flows.
shield volcano
Large and steep-sided, often thousand meters high and tens of kilometres across the base, and composed of layers of both lava and ash.
composite volcano
What is molten, or liquid, rock stored inside Earth called?
magma
Where is the Ring of Fire located?
along the Pacific Ocean shoreline
Which two specific locations have volcanic activity due to divergent plate boundaries.
Mid Atlantic Rift & East African Rift
Are hot spots stationary?
yes
What can hot spots create?
islands - the Hawaiian Islands
If the viscosity is higher, will the fluid move more swiftly, or more gradually?
more slowly
If magma has a high viscosity, will it contain more or less silica?
more silica
What is pyroclastic material?
any solid material that erupts from a volcano
