Three-dimensional broadband modeling of megameter sound propagation from an underwater explosion

A three-dimensional broadband parabolic equation model is utilized to study the 8000-km-long propagation of an underwater explosion sound from the edge of the New Jersey Shelf to Ascension Island in the South Atlantic Ocean. Both the hydrophone data and the model result show evidence of out-of-plane horizontal reflection and diffraction from a seamount along the propagation path. Two distinct acoustic arrival groups are identified with back-azimuth variations pointing toward the explosion location and the seamount. The three-dimensional sound propagation model reproduces complex signal characteristics observed in the hydrophone data with accurate arrival times and azimuths.