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Woods Hole Science Center

Ocean Bottom Seismometer Specifications

• Width on deployment is 1.02 meters or 40 inches and 0.69 meters or 27 inches on recovery.
  
  
• Height on deployment is 0.97 meters or 38 inches and 0.97 meters or 38 inches on recovery.
  
  
• Weight on deployment is 170 kilograms or 375 pounds and 127 kilograms or 275 pounds on recovery.
  
  
• The anchor configuration is a flat metal plate 1.02 meters (or 40 inches) in diameter with a weight of 45.4kilograms. (or 100 pounds).
  
  
• The deployment depth limit is 5,000 meters.
  
  
• The operational temperature limits - (in degrees Celcius) are 5 to 40.
  
  
• The storage temperature limits - (in degrees Celcius) are -20 to 50.
  
  
• The sensors are three, 4.5 Hz L15B geophones and one OAS E-2S hydrophone.
  
  
• The configuration of the geophones is gimbled on 3 axis.
  
  
• The time of day clock is a Seacan Timing Module with a drift rate of 5 x 10-8 per month.
  
  
• The recording system is digital.
  
  
• The digital sampling sample rates are 5,10, and 20 milliseconds. (200, 100 and 50 samples per second).
  
  
• The number of sensor channels that can be recorded is 4.
  
  
• The total dynamic range of th recorded data is 72 dB (AD converter) plus a 30 dB (1-step gain range) for each data point.
  
  
• The raw data is recorded in binary format with header information for each 1 Mgabyte of information.
  
  
• The data is converted to SEGY format after retrieval.
  
  
• The relocation aides are a flashing strobe, VHF radio beacon, and acoustic transponder.
  
  
• The release method is acoustic, with ranging capabilities.
  
  
• The total battery life is 60 days using Alkaline batteries.
  
  
• The total record time is 45 days of continuous recording.
  
  
• The number of OBS's available is 12.
  
  

Links to pages

OBS Home - What is an OBS? - Specifications - Cruise Reports - Related Web Sites