Ch 25.3 & 25.4 Flashcards
what is the boundary that marks a density change between layers
discontiuity
how are discontinuities identified?
by using seismic waves
what are shadow zones?
an are
a where no seismic waves are recorded
what is another term for shadow zones
dead zone
between what degrees do shadow zones fall?
105-140
is the outer core a solid or a liquid?
liquid
is the inner core a solid or liquid
solid
what makes up the lithosphere?
the crust and uppermost mantle
what is the asthenosphere?
a plastic like layer which earth’s plates move
what elements make up the mantle?
calcium, aluminum
which elements make up the core?
iron, magnesium
the measure of a fluid’s resistance to flow
viscosity
the chemical compound silicon dioxide, SiO2, which is a common 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
broad,flat structures composed of layer upon layer of lava flows
shield volcanoes
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 rock stored inside earth is called
magma
where is the ring of fire located?
pacific ocean
what are 2 specific locations where volcanic activity occurs due to divergents?
East African Rift and Mid-Atlantic ridge
are hotspots stationary?
yes
if magma has a high viscosity will it contain more or less silica
more
what is pyroclastic material
any solid material that erupts from a volcano
what is the smallest type of pyroclastic matrial
volcanic ash
what is the largest type of pyroclastic material
blocks and bombs
