Synthetic seismograms have been generated in an attempt to measure the attenuation of compressional waves beneath the Atlantic coast of Nova Scotia; the results suggest that the value of Q must be of the order of 300 whatever the mechanism of propagation may be. Comparison with results of experiments in the Gulf of St. Lawrence shows that attenuation of first events in the range of distance up to 60 km is more rapid in the rocks beneath the Gulf than in those beneath the Atlantic coast of Nova Scotia, This may be due either to attenuation in the upper sedimentary layers, present in the one place but not in the other, or to greater attenuation within rocks in which the compressional wave velocity is the same as in those beneath the Atlantic coast.

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