Force Balanced Broadband Seismometer

Model EP-105


The EP-105 broadband seismometer instruments are econmical, designed as a versatile, rugged broadband active seismic sensors. They consume very low power and are packaged in compact, lightweight aluminum cases. Unlike traditional seismometers, they are based on proprietary electrochemical transducer technology .

These transducers have many advantages over conventional electromechanical sensors. The sensor is equipped with a force-balancing feedback and its noise is reduced by an additional 10dB. The sensors are offered in two application-dependent versions: EP105SM with a higher clip level, and EP105LN 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 EP105 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. 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,
  • Low Power
  • No Mass Centering or Mass Locks
  • High Sensitivity
  • 135dB Dynamic Range
  • Rugged
  • Maintenance Free
  • Waterproof
  • Operates over a wide tilt
  • OBS and Borehole Configurations
Operating principle: Electrochemical motion transducer with force-balancing feedback
Output signals: 2 horizontal, 1 vertical; very broad passband, velocity flat response
Output signal swing: 10 V single-ended; (20 V p-p)
Dynamic Range: 135 dB
Bandwidth: 0.033 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
Waterproof: Submersible (1m)
Temperature range: Standard: -12 to + 55 C
Others optional
BasicEP-105 Configuration The standard configuration includes mating connector and calibration sheets
Sensitivity Option option -Sxxxxx
(x specifies sensitivity)
Low Power Option option -LP
Recorder Options DR-4000,
Supplies and Accessories Sensor Cable
General Spares None

S Printer Friendly Format For Specifications

Case diameter 210 mm
Case height: 210 mm
Weight (Al housing) 6.5 kg
Connector 14-pin circular
Power - Standard 9 - 13 Vdc; 12 Vdc nominal
Supply current Standard: 28 mA; LP version: 7.5mA


Seismometer EP105

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