GL-BH2
Short Period Borehole Seismometer
Main application fields:
Short Period Seismic Observation in Underground
OVERVIEW
Description
The GL-BH2 seismometer, the downhole version of the GL-CS2 short-period seismometer, shares identical core technical specifications with its parent model, designed for underground seismic monitoring. The device comprises a positioning base, orientation unit, alignment mechanism, cable stress reliever, and triaxial mechanical pendulum with feedback circuitry—all housed within a sealed casing. The casing’s base connects to the orientation unit, while its uppersection links to both the alignment mechanism and cable stress reliever. During installation, operatorsf irst install the base in the wellbore using a gyroscope to determine its azimuth. Subsequently, the orientation unit rotates the sealed casing until it aligns with the geodetic coordinate system when seated on the base. Featuring rational structural design, simple configuration, stable performance, tight cement seal, and strong resistance to tilting,the GL-BH2 seismometeris specifically engineered for observation wells within clinationsunder 5°.
GL-BH2 equipment installation diagram

GL-BH2 Wide frequency characteristic dia-gram

Landslide vibration data recorded by GL-BH2

Technical Parameter
▶Mechanical structure: UVW, three-way integrated installation
▶Mode of transduction: displacement transduction
▶Output signal directions: vertical (UD), east-west (EW), north-south (NS)
▶Output physical quantity: ground motion speed
▶Bandwidth: 0.5Hz~80Hz
▶Maximum output signal: ±10V (single end), ±20V(double end)
▶Sensitivity: 2000V/ (m/s)
▶Dynamic range:>140dB
▶Limiting level: 10mm/s@10Hz
▶Horizontal inhibition ratio:> 1%
▶Parasitic resonance:>150Hz
▶Self-noise level: 0.5Hz~10Hz is lower than NLNM
▶Anti-tilt capacity: ≤5°
▶Output resistance: <100
▶Output current:>5mA
▶Load capacitance:>0.01uF
▶Power supply voltage: 9~18V
▶Sensitivity: 9~12 m/ (s^2)/ A
▶Power consumption: 0.8W
▶Zero adjustment and monitoring: built-in zero adjustment motor, support for command zero adjustment and remote monitoring
▶Sealed chamber size: 114mm in diameter and 245mm in height
▶Applicable well inner diameter: 120mm~136mm, standard well inner diameter is 136mm
▶Working temperature: -25℃~60℃
▶Sealing material: 304 stainless steel
▶Sealing method: end face and side surface sealing
▶Sealed plug: waterproof stainless steel connector, support 1000m water depth
▶The depth of the whole machine into the well is 0~1000m
▶Weight: 12kg (seismometer), the whole machine is 25kg (including base, gravity stabilizer and stress reliever)













