Abstract
Data from a 1500-km linear ocean bottom hydrophone array deployment near Wake Island by the Hawaii Institute of Geophysics are used to examine seismic coda and scattering in the northwest Pacific. Two earthquakes in the Kuril Islands that occurred along the trend of the hydrophone array are analyzed in the distance range 2700 to 3700 km. The coda of the oceanic S waves (1.5 to 20 Hz) display: (1) a constant decay rate independent of distance, and (2) an increasing coda energy falloff rate with increasing frequency. Both of these observations suggest that substantial scattering is not occurring in the propagation along the array. The properties of the oceanic S coda are relatively stable when the propagation paths are nearly the same. The observations are consistent with coda generation dominated by back-scattering in the source region rather than from forward-scattering along the propagation path.
