How many layers of material form the interior of the Moon?

The seismic data obtained during the Apollo 11- 17 missions has painted a very interesting picture of the lunar interior. Measurements obtained from bouncing radar pulses off the lunar surface, and by calculating the dynamics of man-made satellites orbiting the Moon, also paint their own picture of the lunar interior.

The Moon's interior seems to be less stratified than the Earth's, and because seismic shocks reverberate for up to an hour or more, the interior cannot be very viscous...molten. The surface is covered by a REGOLITH of shattered rock from innumerable meteor impacts. The depth of this layer is up to 100 meters or so. This is situated on top of the lunar crust or LITHOSPHERE which extends 60 kilometers on the side facing the Earth, and at least 150 kilometers on the back side of the Moon. This crust seems to me richer in titanium and aluminum than Earth crustal rocks. The crust, or at least its outer layer, seems to be poc marked by 'mascons' or 'mass concentrations' which are probably ancient meteors/asteroids that impacted the Moon but were never completely absorbed. These can be identified by the dips in the orbits of spacecraft and other satellites as they pass over them. Below the lunar lithosphere is a region extending 1000 kilometers called the lunar ASTHENOSPHERE. Lunar seismic studies show this region has been at least partially molten in the distant past, suggesting that the lunar core may have been far hotter than it is now. The heat eventually made its way to the surface and cooled of the lunar interior. Below the asthenosphere, seismic shock waves do not seem to travel freely which some astronomers believe means that the Moon has a core region that may still be partially molten.

Including the regolith, this means that the Moon is divided into 3-4 regions. For a lunar radius of 1700 kilometers:

regolith ...... 100 meters
lithosphere.... 60 - 150 kilometers
asthenosphere.. 1000 kilometers
core?.......... 600 kilometers