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Woods Hole Staff Deploys Ocean Bottom Seismometers (OBS) off Los Angeles
The longest deployment to date (a month) of ocean bottom seismometers (OBS) was successfully completed on July 7 offshore Los Angeles by Greg Miller, Jeff Nealon, Joe Newell, Rick Rendigs, Nancy Soderberg, and Uri ten Brink (WHFC). Six OBS were deployed at 100-m intervals on June 10 in 130 m of water north of Redondo submarine canyon. The Southern California Marine Institute boats, the R/V Sea Watch and the R/V Yellowfin were used for deployment and recovery of the instruments. The purpose of the experiment was to test various designs of external geophone packages for the OBS for the purpose of recording earthquakes with fidelity. The mechanical design of the external packages was carried out by Ray Davis (WHFC) and the electronic modifications by Greg Miller (WHFC). The test constitutes comparisons of the recorded amplitude spectrum and the consistency of signals generated by local and tele-seismic earthquakes. During the first test cruise, last October, the WHFC established the superiority of external packages over packages enclosed within the OBS sphere. Following analysis of the results, all 15 OBS will be equipped with external geophone packages. The external geophone packages and other planned modifications are necessary to address a variety of needs required from the OBS in the coming year: two cruises to study seismic properties of gas hydrate sediments, two cruises to monitor local earthquake activity, and one cruise to image the Seattle Basin under downtown Seattle.
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in this issue:
Los Angeles
Association for Women Geoscientists
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U. S. Department of the Interior | U.S. Geological Survey
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