| 摘要 |
A marine seismic source comprises at least one acoustic source 22 and an acoustic ceiling 20 positioned above the source so that a reflection of said acoustic wave from said ceiling is reduced in amplitude compared to reflection of said acoustic wave from a boundary between said water and air. The ceiling may be the underside of a vessel, and the sources may be rigidly attached underneath the ceiling, or suspended by flexible cables. An array of sources may be used, at least one of which is not located under the ceiling so that it does produce a source ghost. The sources in the array may produce acoustic waves having different frequencies, such as 1 Hz to Hz and 10 Hz to 120 Hz. The source may be an air gun or a water gun. The acoustic ceiling may have a high impedance, a high attenuation, or both. |
