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 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. ¿ 2000 American Geophysical Union