TriAxial Forced-Balanced Borehole Accelerometer
( Low Noise Model )

Model 131A-02/BH




  • State-of-the-Art MEMS Force-Balance Accelerometer
  • Low Noise
  • Sensitivity and Offset Stable Over Wide Temperature Range
  • Available in Triaxial, Uniaxial, and
    Borehole Models


  • Free Field Reference
  • Building Arrays
  • Structural Monitoring
  • Site Response
  • Aftershock Studies
Download Brochure


TriAxial Forced-Balanced Accelerometer ( Low Noise Model )

The REF TEK 131A-02/BH is a triaxial Borehole Accelerometer that offers a powerful combination of low noise and excellent stability for subsurface monitoring of ground motion. The 131A-02/BH Accelerometer is housed in a 3-inch diameter stainless steel cylindrical case with a sealed connector, which can be deployed at depths up to 2300 feet (700 meters). The case design allows for a wedging system to be attached for installation instead of using conventional back-filling methods for securing orientation of the accelerometer. The orientation can be monitored by an optional internal digital compass. Also, by using the wedge system, the sensor is retrievable for your reinstallation needs.

The 131A-02/BH Accelerometer provides the industry standard analog output of -10V to 10V full scale. The performance of the accelerometer includes exceptional linearity over a broad dynamic range, excellent bias stability, and little hysteresis errors or offset drift problems that are usually associated with other accelerometer designs.

The 131A-02/BH electronics employ three sensors mounted orthogonally in a rigid internal frame and anchored to the case. Provisions are built-in for mounting the internal digital compass. The modular electronics design consumes low power, only 60mA @ 12 VDC.



REF TEK equipment consists of four major product lines: