Accession Number : ADA187404

Title :   A Deep-Water OBS (Ocean Bottom Seismometer) Array with Real-Time Telemetry.

Descriptive Note : Interim rept.,

Corporate Author : ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE MIAMI FL GEO-ACOUSTIC LAB

Personal Author(s) : Abbott, Charles E ; Yamamoto, Tokuo ; Badiey, Mohsen ; Turgut, Altan

PDF Url : ADA187404

Report Date : Oct 1987

Pagination or Media Count : 34

Abstract : A two-element, ocean bottom seismometer (OBS) array, operating in the ULV/VLF range, has been developed for use at depths at 2000 meters and inter-element spacing to 600 meters Seismic periods between 1 and 200 seconds, accelerations of 10 to the minus 7th meters/sec sq, and pressure fluctuations of 1 pascal are within the system sensing limits. As such, investigations related to ambient ocean noise and low frequency ARI are possible. The array incorporates real-time radio telemetry to provide a user with on-site, quick-look capability while eliminating ship tending and/or anchoring constraints. The array features rapid deployment and retrieval and observational periods of 5 days before recharging the buoy batteries. Total length of array cable is 3020 m. Each element of the array is composed of: a three axis set of medium-period seismometers, a differential pressure gauge and, to determine package orientation, two inclinometers and a north-seeker. All sensor signals are digitized within the underwater package and a single, coaxial mooring cable couples the seismic data from each element to a surface telemetry buoy where it is relayed, via radiofrequency, to a shipboard receiver for immediate storage and real-time analysis. This report describes the system components, characteristics, and specifications.

Descriptors :   *SEISMOMETERS, *RADIO TELEMETRY, *BUOYS, *TELEMETER SYSTEMS, *SEISMIC DATA, DETECTORS, ANCHORS, SIGNALS, ARRAYS, CABLES, LENGTH, OCEAN BOTTOM, QUICK REACTION, REAL TIME, AMBIENT NOISE, OCEANS, PRESSURE GAGES, PRESSURE GRADIENTS, LOW FREQUENCY, VARIABLE PRESSURE, RAPID DEPLOYMENT, RECEIVERS, SHIPBOARD, SURFACES, STORAGE, DETECTION, LIMITATIONS, VERY LOW FREQUENCY

Subject Categories : Seismology
      Marine Engineering
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE