Both P and S waves slow down when they reach this layer
Explanation:
The asthenosphere is the uppermost part of the mantel and is also called the magma chamber. This layer s partly molten in the state is tectonically weak and is a ductile region.
It almost solid and seismic waves tend to be relatively slow through the asthenosphere. The upper-most part of the asthenosphere is believed to be of great rigidity and the brittle lithosphere.
