A new seismic velocity model for the Moon from a Monte Carlo inversion of the Apollo lunar seismic data

A reanalysis of the Apollo lunar seismic data and the subsequent application of an inverse Monte Carlo method to P and S-wave arrival times has resulted in a more detailed lunar velocity structure than previously obtainable. The velocity is seen to increase from the surface down to the base of the crust at 45 +/- 5 km depth. The results furthermore indicate a constant velocity upper mantle extending to 560 +/- 15 km km depth, separated from a more complex high velocity middle mantle by an increase in velocity of 1.0 km/s. In addition, the moonquake locations have been improved. The shallow moonquakes are found to be located in the depth range 50-220 km. The majority of deep moonquakes are concentrated in the depth range 850-1000 km with an apparently rather sharp lower boundary.