Question 24 Which layer of Earth exhibits plastic (ductile) behavior? A) Lithosphere B) Asthenosphere C) Inner core D) Outer core
Answer (1)
The layer of Earth that exhibits plastic (ductile) behavior is the Asthenosphere, which corresponds to option B.
The Earth's structure is divided into several layers based on chemical and physical properties. These layers are:
Lithosphere: This is the outermost layer of the Earth, consisting of the crust and the uppermost part of the mantle. It is rigid and behaves in a brittle manner. The lithosphere includes both continental and oceanic plates.
Asthenosphere: Located beneath the lithosphere, the asthenosphere is part of the upper mantle and exhibits plastic (ductile) behavior. This means it can flow slowly over time, which allows the tectonic plates in the lithosphere to move. The ability to flow is due to high temperatures and pressures, which cause the rocks here to be partially molten or close to their melting point.
Outer Core: The outer core is a liquid layer composed mainly of iron and nickel. Although it is liquid, it does not exhibit plastic behavior like the asthenosphere because it is entirely fluid.
Inner Core: The inner core is solid, primarily composed of iron and nickel, and does not exhibit plastic behavior as it is rigid due to the immense pressures.
Understanding the behavior of these layers is crucial for the study of plate tectonics and volcanic activity, as the movement of tectonic plates is facilitated by the ductile properties of the asthenosphere.
