Geoacoustic Models of the Sea Floor

Experimental Applications of the Modular Acoustic System for the Submersible ALVIN

“…Yet it is this viscoelastic model for ocean sediments that Hamilton (1974) dismisses when he reviews actual measurements of v 2 and a2 ApSparently, the fluid does not move relative to the frame, and thus losses from this source do not occur.…”

“…Although attenuation in sediments expressed in dB/m increases in direct proportion to the frequency (Hamilton, 1974), the beamwidth of the Modular Acoustic System's transducer has decreased from 600 at 3.5 kHz to about 400 at 6.0 kHz. This decreased beamwidth may be an advantage in some situations where increased spatial resolution is necessary, provided the investigator is willing to accept decreased depth of penetration.…”

“…When att~enua-tion values from Fig. 1 of Hamilton (1974) are used, (a 2 /w)v 2 is less than 0,003, and c 2 simplif.…”

“…Extensive measurements of phase velocity and attenuation have been reported in the literature and summarized by Hamilton (1974).…”

“…I' a is determined from Hamilton (1974), who shows a value of 0.15 dB/m at 3.5 kHz for clayey silt and silty clay, increasing I to 2 dB/m for sands.…”