Direct determinationsof the P-waveattenuation parameter, Q,, in the Earth's mantle are made using changes in the form of P-wave amplitude spectra as a function of distance. Two independent sets of experimental data from axisymmetrical surface sources are used: (1) 288 records of narrow-band SVKM seismometers from 19 events, and (2) 75 records of wide-band SVK seismometers from seven larger events.The average Q , value in the depth interval between 100 and 760 km is found to be 710 and in the interval 760-2900 km to be between 1200 and 1330. The estimate of the accuracy of these results is given and the comparison with other authors' results of direct and indirect Q, determination is made.

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One of the possible reasons of the long duration of lunar seismograms are multiple reflec tions in the upper part of lunar cross-section, similar to those generating under Earth conditions. While registration of seismic oscillations in a region with stratified low-velocity sediment rocks of 6-7 km thickness the authors observed long seismic low-decaying oscillations. The observed decay was about 40 db during 30 min.The long duration records are obtained only on the distances where the intense overcritical reflec tions exist from the M-boundary situated at a depth of 50 km.These waves generated numerous multiple reflections, longitudinal, shear and converted waves in the upper part of the cross-section. These body waves are responsible for the generation of the surface waves, recorded in the subsequent parts of the seismograms. Periods of body waves are about 1-1.5 s., those of surface waves -about 1.5-3 s.Extrapolating similar mechanism of the wave generation to lunar media, one should assume the presence of a layered upper part of the cross-section and the possibility of the sufficiently intense wave incidence on its lower bqundary.It is possible if either reflecting boundaries or a vertical velocity gradient are present in the under lying media. The first variant is accompanied with overcritical reflections, the second one -with intense refracted waves.