Final answer:
The asthenosphere is a soft and plastic-like layer in the upper mantle that allows the movement of Earth's tectonic plates. It is crucial for geological events such as earthquakes and volcanic activity due to its involvement in the subduction process.
Step-by-step explanation:
The asthenosphere is a soft, low-velocity layer in the upper mantle, beneath the lithosphere. It is characterized by its semi-fluid, plastic-like behavior, which allows it to flow and move. Unlike the rigid lithosphere that includes both the crust and the uppermost part of the mantle, the asthenosphere is pliable. This plasticity is crucial for the movement of tectonic plates on the Earth's surface.
The Earth's interior layers can be described either by their chemical composition or by their mechanical properties. The lithosphere and asthenosphere are distinguished by their mechanical properties. The ability of the asthenosphere to flow is due to convection currents caused by the heat escaping from the Earth's interior, which facilitates the slow movement of the overlying tectonic plates.
The movement of these plates can result in geological events such as earthquakes, volcanic activity, and the creation of mountain ranges. The asthenosphere plays a fundamental role in these processes, as it is the layer that allows the lithosphere to move and is involved in the process of subduction, where one plate moves under another into the mantle.