Force Balanced Ocean Bottom Broadband Seismometer
Model EP-105OBS

The EP-105OBS Series Ocean Bottom Seismometer instruments are designed as, versatile, rugged broadband active seismic sensors. They consume very low power and are packaged in compact, lightweight PVC cases. Unlike traditional seismometers, they are based on proprietary electrochemical transducer technology .

These transducers have many advantages over conventional electromechanical sensors. All senor components are equipped with a force-balancing feedback. The sensors are offered in two application-dependent versions: EP105OBS-SM with a higher clip level, and EP105OBS-LN with reduced noise. Both models have the same dynamic range, which is shifted up by approximately 10db in the 'SM' relatively to the 'LN' version.

The EP105OBS has an exceptionally rugged design and DOES NOT require mass lock or mass centering, or special installation equipment or procedures. The units are operational in a wide range of installation tilts. They are suitable for both Bentho's and Titanium cylinder installation. Optional inclinometers may be installed.

These seismometers provide a low cost of ownership, REQUIRING no maintenance over the life of the instrument. Three and five-year extended warranties are available.

  • Passband 0.033 Hz to 50 Hz, Optional 0.0167 Hz
  • Low Power
  • No Mass Centering or Mass Locks
  • High Sensitivity
  • 135dB Dynamic Range
  • Rugged
  • Maintenance Free
  • Operates over a wide tilt
  • Flat Frequency Response
Operating principle: Electrochemical motion transducer with force-balancing feedback
Output signals: 2 horizontal, 1 vertical; very broad passband, velocity flat response
Output signal swing: (Vcc-1) single-ended; 2(Vcc - 1) differential
Dynamic Range: 135 dB
Bandwidth: 0.033 Hz - 50 Hz;
Optional.: 0.0167 Hz - 50 Hz
Self-noise: LN -160dB; SM -148dB on the USGS NLNM
Generator constant: Standard: 2000 V/m/s; Opt.: 350 - 20,000 V/m/s
Mass Centering: NONE REQUIRED
Maximum installation tilt 15
Mechanical resonance >150 Hz
Case Vacuum tight to 0.5 atm
Temperature range: Standard: -12 to + 55 C
Others optional
Basic EP-105OBS Configuration The standard configuration includes mating connector and calibration sheets
Extended Period

option -0167Hz

Sensitivity Option option -Sxxxxx
(x specifies sensitivity)
Recorder Options DAS-6502
Supplies and Accessories Sensor Cable
General Spares None

S Printer Friendly Format For Specifications

Case diameter Custom
Case height: Custom
Weight (Al housing) Custom
Connector Threaded hole M12 on the top
Power - Standard 6 - 16 Vdc; Optional: (6 - 16) Vdc;
Supply current 7.5mA



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