Force Balanced Very Broadband Ocean Bottom Seismometer
Model EP-300 OBS

The EP300-OBS represents the new generation of low noise very broadband ocean bottom seismometers for OBS applications.

The sensor's advanced force-balancing feedback provides for an extended dynamic range, excellent stability and linearity across the entire passband. This instrument uses three proprietary electrochemical transducers with identical responses mounted orthogonally along the N, E, and Z-axes. These transducers have many advantages over traditional electromechanical sensors. In particular, they have much larger ground motion-to-voltage conversion ratio that results in a uniquely shaped noise curve that is essentially flat from several Hertz to the longest periods.

Like our other seismometers, the EP300-OBS is extremely rugged which makes it ideal for OBS use. This seismometer does not require a mass lock, mass centering, or special installation equipment or procedures. It has very low power consumption, operates over a wide temperature range; and stays operational within a wide range of installation tilts (optional inclinometer to measure installation tilt). It provides low cost of ownership, requiring no maintenance over the life of the instrument. Options include internal inclinometers. Three and five-year extended warranties are available.

  • Passband 0.0167 Hz to 50 Hz, Optional 0.01 Hz and 0.008 Hz
  • Low Power
  • No Mass Centering or Mass Locks
  • High Sensitivity
  • 150dB Dynamic Range
  • Rugged
  • Maintenance Free
  • Operates over a wide tilt
  • Flat Frequency Response
  • Force Balanced
  • Calibration Inputs
Operating principle: Electrochemical motion transducer with force-balancing feedback
Output signals: 2 horizontal, 1 vertical; very broad passband, velocity flat response
Output signal swing: 7.5 V (15 V p-p)
Dynamic Range: 150 dB @ 1Hz
Bandwidth: Standard: 0.0167 - 50 Hz; Optional.: 0.01 - 50 Hz
Self-noise: Below USGS NLNM in 0.05 - 5Hz range; -170dB @ 0.033Hz.
Generator constant: Standard: 2000 V/m/s; Opt.: 350 - 20,000 V/m/s
Calibration input 1kohm; 1V in - 1V out; individual for each channel
Mass Centering: NONE REQUIRED
Maximum installation tilt 10
Mechanical resonance >150 Hz
Case Customized to application
Temperature range: Standard: -12 to + 55 C
Others optional
Basic EP-300-OBS Configuration The standard configuration includes mating connector and calibration sheets
Extended Period

option -01Hz or -008Hz

Sensitivity Option option -Sxxxxx
(x specifies sensitivity)
Full Scale Output (+/-15V) Option option -FS15
Recorder Options DAS-6502
Supplies and Accessories Sensor Cable
General Spares None

S Printer Friendly Format For Specifications

Case diameter Customized to application
Case height: Customized to application
Weight Customized to application
Connector Customized to application
Power - Standard 10 - 15 Vdc; 12 Vdc nominal
Supply current 10mA


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