1. Earth’s layered structure 8.4

2. Crust The thin, rocky outer layer of Earth.

3. Mantle The 2890-Kilometer-thick layer of Earth located below the crust.

4. Lithosphere The rigid outer layer of Earth, including the crust and upper mantle.

5. Asthenosphere A weak plastic layer of the mantle situated below the lithosphere; the rock within this zone is easily deformed.

6. Outer Core A layer beneath the mantle about 2260 kilometers thick; the outer core contains liquid iron and generates Earth’s magnetic field.

7. Inner Core The solid innermost layer of Earth, about 1120 kilometer in radius.

8. Moho The mohorovicic discontinuity, which is shortened to moho; it is the boundary separating the crust from the mantle, discernible by an increase in the velocity of seismic waves.

9. Key Concept What is Earth’s internal structure? Earth’s interior consists of three major zones defined by its chemical composition--the crust, mantle, and core.

10. Key Concept What is the composition of Earth’s interior? Earth can be divided into layers based on physical properties—the lithosphere, asthenosphere, outer core, and inner core.