Earth Sci_L7.1 Earth's Interior and Seismic Waves

What are the three main layers of Earth's interior identified by geologists?

• Crust, Lithosphere, Asthenosphere

• Crust, Mantle, Core

• Outer Core, Inner Core, Mantle

• Lithosphere, Mantle, Core

Which of the following provides direct or indirect evidence about the composition of Earth's interior?

• Ancient volcanic eruptions bringing up xenoliths

• Ophiolites, which are pieces of oceanic crust and upper mantle

• C1 chondrites, meteorites made of Earth's parent material

• All of the above

What is the precise location within Earth's crust where an earthquake's energy burst occurs?

• Epicenter

• Fault line

• Focus

• Blind Zone

Which type of seismic wave is compressional, moves parallel to its propagation, and is the fastest to arrive at a seismic station?

• Love Waves

• Rayleigh Waves

• S-Waves

• P-Waves

What factors influence how seismic waves interact with Earth's interior as they travel through different layers?

• Density, temperature, and state of rock

• The presence of surface waves only

• The type of fault causing the earthquake

• The magnitude of the earthquake

What characteristic of Earth's outer core is inferred from the S-wave shadow zone?

• It is solid.

• It is gaseous.

• It is liquid.

• It is composed of light elements.

The Mohorovičić discontinuity marks the boundary between which two layers of Earth?

• The outer core and the inner core.

• The crust and the mantle.

• The lithosphere and the asthenosphere.

• The mantle and the outer core.

What is the primary characteristic of the low-velocity zone (LVZ) in Earth's mantle?

• A sudden increase in seismic wave velocities.

• A transition from weak, ductile rocks to strong, brittle rocks.

• A decrease in body wave velocity due to partial melting of mantle rock.

• The boundary between the outer core and the inner core.

What is the significance of the asthenosphere in relation to tectonic plates?

• It is a rigid layer that prevents plate movement.

• Tectonic plates move along its top, as it is the most ductile area of the mantle.

• It is where S-waves dissipate, indicating a liquid state.

• It is the layer where olivine changes its crystal structure to become more dense.

What is a proposed explanation for the ultra-low velocity zones (ULVZ) found at the base of the D'' layer?

• They are areas where subducted slabs accumulate, increasing seismic velocities.

• They represent regions of partial melting caused by increased heat flux from the core.

• They are composed entirely of solid, dense rock, leading to high seismic velocities.

• They mark the boundary between the liquid outer core and the solid inner core.