## Abstract

Direct path measurements of a single-bottom interacting path on a vertical array are used to probe the seabed structure. The phase of the cross-spectrum, commonly used in engineering acoustics, permits examination of the importance of subbottom paths. When the cross-spectral phase is linear with frequency it implies that source to receiver propagation is dominated by a single path. A linear cross-spectral phase would also satisfy the linear seabed reflection coefficient phase approximation sometimes employed in forward modeling and geoacoustic inversion approaches. Shallow water measurements of the cross-spectrum, however, evidence a strongly nonlinear phase, below about 1500 Hz at one site, and 600 Hz at another site, implying that: 1) the subbottom structure plays an important role (i.e., a seabed half-space approximation would be inappropriate); and 2) the linear reflection phase approximation would be violated at those frequencies.

Original language | English (US) |
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Article number | 5766773 |

Pages (from-to) | 248-258 |

Number of pages | 11 |

Journal | IEEE Journal of Oceanic Engineering |

Volume | 36 |

Issue number | 2 |

DOIs | |

State | Published - Apr 2011 |

## All Science Journal Classification (ASJC) codes

- Ocean Engineering
- Mechanical Engineering
- Electrical and Electronic Engineering