First seismic receiver functions on the Moon

We applied the S receiver function technique [Farra and Vinnik, 2000] to the recordings of deep moon‐quakes at seismograph station Apollo 12 in order to detect phases converted (Sp) and reflected beneath the station. We detected Sp phases from the base of the surficial low‐velocity zone and from the mantle‐crust boundary. The average P velocity in the surficial layer 1 km thick should be a few times higher than in reference model [Toksoz et al., 1974]. The observed time, amplitude and waveform of Sp phase from the mantle‐crust boundary are close to those predicted by the reference model but with a modified surficial layer. The S wavetrains within the first 10 s may contain waves scattered in the mantle. This scattering is stronger than in the Earth at comparable depths. The polarized component in the coda waves that we observe is another previously unknown phenomenon.