A reflected energy prediction model for long-range hydroacoustic reflection in the oceans^a)

Acoustic energy from underwater earthquakes and explosions can propagate over long distances with very little attenuation in the deep ocean. When this sound encounters a seamount, island, or continental margin, it can scatter and again propagate over long distances. Hydrophones in the deep sound channel can detect these reflections tens of minutes or hours after arrivals from the direct source-to-receiver path. This paper presents the Reflected Energy Prediction (REP) model, a model for predicting these reflected arrivals. For a given source and receiver, the REP model uses a detailed knowledge of the underwater environment and components of the Hydroacoustic Coverage Assessment Model, HydroCAM, to predict the impulse response of the ocean. When this impulse response is convolved with a source function, a waveform envelope prediction is made that can be compared with recorded data. In this paper we present the model and a few applications of the model using data recorded from earthquakes and explosions in the Atlantic and Indian Oceans. These examples illustrate the use of the model and initial steps toward model calibration.