CMG-3T

The CMG-3T is a compact three-component broadband sensor, suitable for surface vault (observatory), subsurface vault and posthole installations.

Features

Covers the complete seismic spectrum with a single transfer function
120 s – 50 Hz standard response
Truly portable with lifting handle and convenient access to connectors
High linearity: >107 dB horizontal, 111 dB vertical (USGS figures)
Over 140 dB dynamic range over the entire passband (USGS figure)
Cross-axis rejection over 65 dB
Sensor axes orthogonal to within 0.1 °
Remote electronic mass locking, unlocking and centring
Adjustable feet allow for up to 5 ° tilt
Low power consumption (750 mW from 10 . 30 V input power)

Options

The slimline CMG-3T.

Response options from 1 – 360 s to 50 – 200 Hz
Slimline form factor for posthole installations
Waterproof connectors
CMG-3TD digital output instrument
CMG-3TB borehole form factor

Noise performance

The noise equivalent input acceleration and Brownian noise of the CMG-3T is well below the background noise level encountered at the quietest site on earth. The noise level of the sensor transducer is at least 20 dB less than the Brownian noise of the instrument (set to 0.195 dB rel. 1 m²/s⁴/Hz acceleration).

The plots below estimate the system noise power of the vertical component of the 3T conventional-response sensor. The system noise power, corrected for system response and gain, is shown as a continuous thin line; the circled line is the raw non-coherent power spectrum. The thicker line is the Peterson New Low Noise Model (NLNM).

Measured self-noise of the CMG-3T, vertical component.

Hybrid response

Response of a hybrid instrument.

This is an optional response type originally developed for the US National Seismic Network, which fully utilises the capabilities of a force-feedback seismometer to provide the most useful balance of noise performance and dynamic range.

An instrument with hybrid response outputs signals proportional to acceleration at low frequencies, and proportional to velocity at high frequencies.

CMG-3T

Features

Options

Noise performance

Hybrid response

CMG-3 news

Complete CMG-3T vault installation

New borehole instruments for the South Pole

A stable foundation for cutting-edge physics



Home Products CMG-3T CMG-3TD CMG-3ESP Compact CMG-3ESPD Compact CMG-5T CMG-5TD CMG-5T Compact CMG-40T CMG-6TD CMG-CD24 CMG-DM16 CMG-DM24 CMG-DCM CMG EDU All products Software New installations Customer support About us	CMG-3T CMG-3T The CMG-3T is a compact three-component broadband sensor, suitable for surface vault (observatory), subsurface vault and posthole installations. Datasheet Manual (PDF) Manual (HTML) Quick start sheet Features Covers the complete seismic spectrum with a single transfer function 120 s – 50 Hz standard response Truly portable with lifting handle and convenient access to connectors High linearity: >107 dB horizontal, 111 dB vertical (USGS figures) Over 140 dB dynamic range over the entire passband (USGS figure) Cross-axis rejection over 65 dB Sensor axes orthogonal to within 0.1 ° Remote electronic mass locking, unlocking and centring Adjustable feet allow for up to 5 ° tilt Low power consumption (750 mW from 10 . 30 V input power) Options The slimline CMG-3T. Response options from 1 – 360 s to 50 – 200 Hz Slimline form factor for posthole installations Waterproof connectors CMG-3TD digital output instrument CMG-3TB borehole form factor Noise performance The noise equivalent input acceleration and Brownian noise of the CMG-3T is well below the background noise level encountered at the quietest site on earth. The noise level of the sensor transducer is at least 20 dB less than the Brownian noise of the instrument (set to 0.195 dB rel. 1 m²/s⁴/Hz acceleration). The plots below estimate the system noise power of the vertical component of the 3T conventional-response sensor. The system noise power, corrected for system response and gain, is shown as a continuous thin line; the circled line is the raw non-coherent power spectrum. The thicker line is the Peterson New Low Noise Model (NLNM). Measured self-noise of the CMG-3T, vertical component. Hybrid response Response of a hybrid instrument. This is an optional response type originally developed for the US National Seismic Network, which fully utilises the capabilities of a force-feedback seismometer to provide the most useful balance of noise performance and dynamic range. An instrument with hybrid response outputs signals proportional to acceleration at low frequencies, and proportional to velocity at high frequencies. CMG-3 news Complete CMG-3T vault installation Best practices for installing a weak-motion sensor in a vault, and how to connect the instrument to a CMG-DM24 digitizer and (optionally) a CMG-DCM. New borehole instruments for the South Pole December 2006 A new-generation CMG-3TB instrument with adaptations for cold conditions is headed for the South Pole as part of a major upgrade to the world's quietest seismic station. A stable foundation for cutting-edge physics August 2006 An active vibration isolating platform based on an instrument from Güralp Systems is helping to provide new insights into atomic physics. More articles on this topic...