Normal-Incidence, High-Frequency Bottom Penetration in the Soft Gassy Sediment of Eckernforde Bay, Germany
NAVAL RESEARCH LAB STENNIS SPACE CENTER MS HIGH FREQUENCY ACOUSTICS SECTION
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Normal incidence, high frequency acoustic bottom penetration measurements were made in the gassy sediment of Eckernfoerde Bay, Germany. Measurements were made of water sediment insertion loss and signal level as a function of frequency and hydrophone depth. Results showed that hydrophones located in a gassy sublayer had signal levels that were higher than the signal level at a hydrophone located just below the sediment water interface. This increase in amplitude is attributed to reverberation from free methane bubbles excited near and above their resonant frequency.