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30-DAY OCEAN-BOTTOM SEISMOGRAPH, ALEUTIANKURILE OPERATIONS
TEXAS INSTRUMENTS INC DALLAS SCIENCE SERVICE DIV
The 30-day ocean-bottom seismograph senses ground motion through 1 vertical and 2 horizontal velocity seismometers and pressure variations through a transducer capable of response to 1.0 cps. Data are recorded continuously on magnetic tape and the unit has a depth capability of 25,000 ft. During the summer and fall of 1964, several drops were made in the area south of the Aleutian chain and northeast of the Island of Hokkaido, Japan. Power density spectra of ambient noise samples over a long time interval were selected from the two areas. Plots of these data vs time are presented and compared with simultaneous meteorological maps covering the respective areas. These results show a direct relationship between ambient noise levels and local meteorological changes. In fact, lowpressure disturbances were observed to cause up to 20 db increase in ambient noise level in the 0-2.0 cps range. Ambient noise levels that previously were observed and reported appear consistent with current findings.
Final rept. for 1 Oct 1964-31 Aug 1965
Approved for public release; distribution is unlimited.