what is the asthenosphere?
The asthenosphere is the highly viscous, mechanically weak and ductilely deforming region of the upper mantle of the Earth.The asthenosphere is generally solid although some of its regions could be melted (e.g. below mid-ocean ridge). The lower boundary of the asthenosphere is not well defined. The thickness of the asthenosphere depends mainly on the temperature is involved in plate tectonic movement and isostatic adjustments. For lecture on Asthenosphere visit