The firm layer between the crust and the asthenosphere is called?
The Correct Answer and Explanation is:
The firm layer between the Earth’s crust and the asthenosphere is called the lithosphere.
The lithosphere is the outermost shell of the Earth, and it consists of the crust and the uppermost part of the mantle. It is rigid, solid, and relatively cool compared to the underlying asthenosphere, which is partially molten and behaves in a more plastic manner. The lithosphere is divided into tectonic plates, which float on the more fluid-like asthenosphere beneath them.
The lithosphere and asthenosphere differ in their physical properties. The lithosphere is solid and relatively brittle, which is why tectonic plates fracture and move over time. The asthenosphere, on the other hand, is less rigid and behaves in a semi-fluid manner due to the higher temperatures and pressures found at these depths. This allows the lithosphere to float and shift, which is a fundamental aspect of plate tectonics.
The boundary between the lithosphere and the asthenosphere is called the lithosphere-asthenosphere boundary (LAB). The lithosphere is typically between 70 to 150 km thick, depending on whether it is continental or oceanic crust. The asthenosphere, located below the lithosphere, extends from approximately 100 km to about 700 km deep into the mantle.
Tectonic activity such as earthquakes, volcanic eruptions, and the movement of continents is driven by the interactions between the lithosphere and the underlying asthenosphere. The movement of tectonic plates over the asthenosphere is also responsible for the creation and destruction of ocean basins, mountain ranges, and other geological features.
