Asthenosphere. Introduction The asthenosphere is the layer of the Earth that lies below the lithosphere. It is a layer of solid rock that has so much pressure and heat the rocks can flow like a liquid. The rocks are less dense than the rocks in the lithosphere. read more
The asthenosphere is almost solid, although some of its regions could be molten (e.g., below mid-ocean ridges). The lower boundary of the asthenosphere is not well defined. The thickness of the asthenosphere depends mainly on the temperature. read more