Question

What is the asthenosphere made of?

Answer 1

There is no liquefied part in the asthenosphere that is in-between lithosphere above and upper mantle below. It is a low-viscosity shell. It is softer than lithosphere in reacting to stress.

Explanation:

Asthenosphere extends from about 60 miles down to about 450 miles.

Both primary and secondary seismic waves are propagated through asthenosphere.