Analyses of oceanic P and S data from an earthquake in the Kuril Islands which occurred along the trend of a 1500-km-long ocean bottom hydroplane array deployment near Wake Island have yielded constraints on high-frequency seismic attenuation in the western Pacific. Spatial attenuation and Q were determined for group velocities between 8.2 and 3.0 km/s and for frequencies between 2.5 and 22.5 Hz. There is greater attenuation of oceanic P than oceanic S at all frequencies suggesting either the presence of significant bulk attenuation in the lithosphere or that oceanic P propagates as a leaky mode. The apparent attenuation of oceanic P and S is distance-dependent, with lower attenuation beyond 30¿ Δ. The apparent Q of oceanic P increases with frequency as Q~f0.7, from about 300 at 2.5 Hz to 1500 at 17.5 Hz. The apparent Q of oceanic S increases with frequency as Q~f1.1, from about 400 at 2.5 Hz to 3000 at 22.5 Hz. ¿ American Geophysical Union 1987