αALPHA-TA120-VEL.

ALPHA-TA120-VEL

Product Overview

Alpha is a three component low noise feedback, velocity output broadband seismometer designed by Dr. C.M. Güralp. In the 1970's and 1980's Dr. Güralp, set out the standards for miniature surface and borehole broadband seismometers. The seismometer is based on orthogonal three axis low noise sensor modules with double nested feedback loop topology.

The mechanical suspension system is based on the principles of “elastica” and the leaf spring is deployed in a “Zero” Length spring topology.

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GaiaCode Broadband Seismometer - ALPHA-TA120-VEL

The ALPHA family sensors are a three components low noise feedback velocity output broadband seismometer suitable for local, regional and teleseismic recording.

ALPHA-TA120-VEL

Instrument Specifications

Suitability

  • Single or large scale seismic networks
  • Micro-seismic monitoring
  • After-shock monitoring
  • Volcanology
  • Hydrocarbon exploration
  • Permanent reservoir monitoring
  • Induced seismicity detection
  • Explosion monitoring
  • Post hole seismology
  • Micro-seismic monitoring

Benefits

  • High data quality broadband data
  • Suspension system with high cross axis rejection
  • Broadband data with high frequency response extending to 150 Hz
  • Automatic self-installation and zeroing for quick installation
  • Tilt tolerance of ±5 degrees
  • Portable and easy to deploy
  • Waterproof with connectors mated

ALPHA-TA120-VEL

Key Features

The mechanical sensor orientation is Non-Galperin with >-75 dB cross axis rejection on all axis.

The sensor Alpha-T120-Vel frequency response covers the complete seismic spectrum with a flat and repeatable frequency response (No peaks) from 0.008333 Hz (120 seconds) to 150 Hz.

Optional Frequency Response VBB sensor, Alpha-T360-Vel. Response 0.00277 Hz (360 seconds) to 150 Hz.

The sensor noise level crosses (below) the New Low Noise Model (NLNM) from 18-20 Hz to 180- 220 Seconds period.

Truly portable rugged seismometer with fine pitched adjustable feet manufactured from phosphor bronze.

Remote electronic control of mass lock and unlocking facility, both with serial interface and logic levels.

Two stage galvanically isolated electronics circuitry.

The sensor mechanical section and the feedback electronics sections have their own isolated and hermetically sealed enclosures.

The electronic and the mechanical sections of the sensor can be physically separated for observatory applications. This is an optional feature and the only VBB broadband sensor that can be configured to have separate mechanical and electronics sections.

Power consumption, less than 1 Watt. Operates from 9 to 36 Volt range, with input power polarity protection.

All analogue outputs and digital inputs are transient protected.

The mechanical sensor section can be installed in a specially carved granite housing for observatory applications.

Disclaimer: The product specifications and the stated data are subject to change without prior notice.

REFERENCES

Ref 1: GURALP C.M. Patent Application, No: 7909579 Filed: 19th March 1979 (declaration priority from Appln No: 10279/78 Filed: 15th March 1978) “Vertical Seismometer”.
Ref 2: GURALP, C.M., “The Design of a Three-component Borehole Seismometer”, 1980. Ph.D. Thesis, Univ of Reading
Ref 3: USHER, M.J., BURCH, R.F. and GURALP, C.M., “Wide-band Feedback Seismometers”, 1979. Physics of the Earth and Planetary Interiors, 18: 38-50.
Ref 4; M,J, USHER and C.M. Guralp, “The design of miniature wideband seismometer” Geophys. J.R. ast. Soc. (1978)-55 (605-613)

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References

  • Ref 1 USHER, M.J., BURCH, R.F. and GURALP, C.M., “Wide-band Feedback Seismometers”, 1979. Physics of the Earth and Planetary Interiors, 18: 38-50.
  • Ref 2 M,J, USHER and C.M. Guralp, “The design of miniature wideband seismometer” Geophys. J.R. ast. Soc. (1978)-55 (605-613) ,
  • Ref 3 GURALP, C.M., “The Design of a Three-component Borehole Seismometer”, 1980. Ph.D. Thesis, Univ of Reading.
  • Ref 4 GURALP C.M. Patent Application, No: 7909579 Filed: 19th March 1979 (declaration priority from Appln No: 10279/78 Filed: 15th March 1978) “Vertical Seismometer”.
  • Ref 5 GURALP C.M. United States Patent Application Number: 4,280.206 March 1979. SEISMOMETERS.
  • Ref 6 GURALP C.M. UK Patent Application GB 2-144-287-A. July 1983 Analog-to-digital converters for Seismometers. The National Research Development Corporation (UK)
  • Ref 7 GURALP C.M. UK Patent Application No. 1900719.4; Title: Infrasound Detector [M&S-IRN.FID4315516]