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Date
1996
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Show full item recordAbstract
Acoustic ranging on the sea floor is one of hopeful methods by which the detection of crustal deformations could be realized in the deep sea. We have been developing a Sea Floor Acoustic Ranging system (SeaFAR) which will detect the strain for a baseline 1 km long with accuracy of 1 cm. SeaFAR repeats the measurement of propagation time of acoustic signal in two way as well as sound velocity in a period longer than a year. Sound velocity is not directly measured but derived from water temperature, salinity and water pressure observed. We have developed one pair of prototypes which measure precise propagation time of acoustic signals, and carried out an experimental measurement on the sea floor 1250 m deep in the Sagami Bay. The result shows that propagation time of acoustic signals can be measured with accuracy of 2x10-6 second and that propagation time varies more than 200x 10-6 second because of the temperature variation in the order of 0 .1℃. It is a next important theme to eliminate of influence of the temperature variation by means of precise measurement of temperature.Journal
Report of Hydrographic and Oceanographic ResearchesIssue/Article Nr
32Page Range
pp.89-99Resource/Dataset Location
https://www1.kaiho.mlit.go.jp/GIJUTSUKOKUSAI/KENKYU/report/rhr32/rhr32-09.pdf