sub-bottomn.adj.

1871 Photogr. Mosaics 94 I forgot to say that I have a perforated sub-bottom to the case, through which I force steam from below.

1894 Official Gaz. (U.S. Patent Office) 4 Dec. 1233/1 In a flower-box... a bottom having perforations, flanges supporting said bottom, a concave sub bottom having a central opening [etc.].

1975 Background Papers on Seafloor Engin. (National Res. Council (U.S.). Committee on Seafloor Engin.) I. 355 The physical parameters that affect these characteristics, such as..seafloor roughness, sub-bottom stratification..temperature gradients in the sub-bottom.

2009 K. G. Foot in R. J. Beamish & B. J. Rothschild Future Fisheries Sci. in N. Amer. xviii. 313 [Acoustic methods]..can sense both organisms and their habitat, including water column, bottom, and sub-bottom.

1902 C. A. Bates Art & Lit. Business 370 I have seen an ad of an advertising agent who claimed to have ‘sub-bottom rates’.

1949 Trans. Amer. Geophysical Union 30 7 The most clear-cut sub-bottom echoes are found in the region which shows least topographic relief.

1968 R. W. Fairbridge Encycl. Geomorphol. 1227/2 Sub-bottom acoustic profiling..has demonstrated many wave-cut terraces partly hidden beneath a thin veneer of late Holocene sediments.

1975 Petroleum Rev. 29 103/1 Sub-bottom profiler.

2002 Colgate Scene (Colgate Univ., Hamilton, N.Y.) Jan. 2/4 The new view of the sedimentary structures and channel dynamics was made possible by bringing the latest technology in sub-bottom sonar profiling from the United States.