Earth's Interior #1

Which one of the foll owing best characterizes the asthenosphere?

A zone of softened peridotite in the upper mantle

Who discovered the crust-mantle seismic discontinuity? In what year?

Andrija Mohorovičić, 1909

Which of the following rocks are closest to the average chemical composition of the oceanic crust?

Basalt and gabbro

What is the upper layer of the lithosphere called?

Crust

Which layer of Earth has the smallest volume?

Crust

Which of the following are probably major components of Earth's inner core?

Crystalline iron and nickel

Which layer of Earth is very dense and solid and consists most likely of an iron-rich alloy?

Inner core

Which of Earth's layers is marked at its top by the Mohorovičić discontinuity?

Mantle

Where does Earth's magnetic field originate?

Outer core

Which layer of Earth does not transmit S waves?

Outer core

Which layer of Earth transmits P earthquake waves but not S earthquake waves?

Outer core

What is the best evidence of Earth having a solidified inner core?

P waves travel faster in the inner core than in the outer core.

Which rock type listed below is probably closest in chemical composition to the upper mantle?

Peridotite

Which of the following includes the zone called the "asthenosphere" (the "weak sphere")?

Upper mantle

What causes Earth's magnetic field?

Weak electrical currents associated with fluid motions of molten iron in the outer core causes Earth's magnetic field.