What does the asthenosphere consist of?

The asthenosphere is primarily characterized as a semi-fluid layer located beneath the lithosphere. This layer is crucial for the movement of tectonic plates, as its semi-plasticity allows the lithosphere, which is the rigid outer layer of the Earth, to glide over it. This movement occurs due to convection currents within the mantle, which create forces that drive the tectonic plates. Understanding the nature of the asthenosphere is key to comprehending plate tectonics and how geological phenomena such as earthquakes and volcanic activity occur, since the interactions of the plates are directly influenced by the conditions present in the asthenosphere.