Quiz 2 Flashcards
• Earth is divided into three
distinct layers.
• These layers are composed of
the thin outside crust, a fluid
region in the middle wherein
Earth’s mass is concentrated,
and a solid inner core.
Earth’s interior
• Outermost layer of the
Earth.
• Made up of oceanic and
continental crust.
•Oceanic crust is a dense and
thin layer that lies under the
ocean basins. (basalt)
• Continental crust is thicker
and lighter than the oceani
crust. (granite and andesite)
Crust
• A layer beneath the crust.
• Made up of solid rock and
lies between the core and
the crust.
• 2,900 km thick and has a
mass of 4.01 x 10 kg.
• Contributes 67% of the total
mass of Earth.
•Hot and dense due to the
temperature and pressure
increases with depth.
• Peridotite made up of iron
and magnesium.
• Heat flows outward trough the
processes of conduction and
convection.
• Heat coming from the core
travels through the atoms by
rapid collision with one
another.
• Convection cells responsible
for the movement of the crust.
• As the materials move above
the mantle, they cool down and
start to sink back, replacing
the hot materials that were
heated by the core.
Mantle
• Inner part of the Earth.
• The first one to formed during
the early years of the Earth.
• Made up of iron and nickel
alloy, which is the reason for
Earth’s magnetic field.
• Makes up 31% of Earth’s
composition.
• Source of Earth’s internal heat.
• The heat released by the core is
due to radioactive decay inside.
• Divided into inner and outer
core
Core
Lithosphere
Asthenosphere
Mesosphere
Outer core
Inner core
Mechanical layers of the Earth
Named after Croatian seismologist Andrija Mohorovicic who discovered its existence in 1909.
• Is one of the boundaries that exhibit the
sudden change in seismic velocity.
• Can be found in the boundary between the mantle and the crust.
• Seismic waves abruptly change from a constant difference at a distance greater
than 200km from the epicenter.
Mohorovic discontinuity
Named after Beno Gutenberg in 1913.
• P-wave slows down and hinders the
movement of the S-wave.
• This discovery proves that S-waves
cannot travel in liquid regions.
• The core is made up of molten materials
because it does not allow S-waves to
penetrate it.
• The boundary at which the mantle meets
the core has been called Gutenberg
discontinuity.
Gutenberg discontinuity
Named after Danish seismologist and
geophysicist Inge Lehmann.
• The core is made up of a molten region
and a solid region.
• A sudden increase in the P-wave and S-wave velocities at a depth of 220km.
• In the region betwee inner and outer
core exists a boundary
Lehmann discontinuity
