Model
Digital Document
Publisher
Florida Atlantic University
Description
An in situ acoustic measurement system was developed to estimate the compressional wave attenuation of marine sediments. The system uses acoustic probes to measure a wideband acoustic pulse traveling horizontally though various sediments. The system transmits a 20 millisecond frequency-modulated (FM) pulse swept from 3 to 50 kHz and match filters the received signals. A special ratio of data collected at two horizontal ranges from the source is used to estimate attenuation as a function of frequency. Data is collected with the in situ system and a chirp subbottom profiling sonar at two offshore sites to compare the attenuation of horizontally and vertically traveling waves in sediment. The collected data is also used to determine the feasibility of remotely estimating in situ attenuation using a chirp sonar. In situ and chirp sonar estimates agree and fall within the range of attenuation measurements made by other investigators in similar sediments.
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