THETA Standard

Product Overview

At the heart of each THETA seismometer are three newly designed seismic sensors with a truly rectilinear suspension of their inertial masses. Unlike pendulous or parallel spring suspension systems our rectilinear system has virtually no observable spurious modes of resonances at higher frequencies. This allows all THETA seismometers to have a flat repsonse to ground motion velocity between 120 sec and 150 Hz with a high cross axis rejection.

The unique design of the connector turret provides not only easy access to the connectors and cabling. It also make the instrument water proof, when a potted connector is mated.

Thumbnail Image

THETA Standard Version

Key Features

Instrument Design

- Classical orthogonal sensor topology with sensor axes pointing in the three cardinal directions.

- Fine pitched adjustable feet manufactured from brass.

- All sensor components are made of non-magnetic materials, minimizing noise induced by outside magntic fields

Instrument Characteristics

- Flat frequency response from 0.008333 Hz (120 seconds) to 150 Hz.

- Other response options: 0.033 Hz (30 sec) to 150 Hz and 0.0166 Hz (60 sec) to 150 Hz.

- Lowest spurious resonance: 340 Hz on both vertical and horizontal sensors.

- Operational range within +/- 10.0 degrees of tilt.

- Offered in a whole range of sensitivities from 2*750 to 2*5000 V/m/s (differential output)

- Cross axis rejection >-70 dB.

- Operating temperature range: -20 to 75 deg C.


- Rugged housing made from hard anodized aluminium.

- Weight 3.1 kg.

- Dimensions: outer diameter 13.8 cm, height 18.5 cm

- Waterproof as per IP68 standard.

 Power and Electronics

- Power consumption 490 Milliwatt at 12 V for 120 sec version, 420 mW for 30 sec version.

- Power operating range from 9 to 36 Volt.

- The sensor's electronic circuitry is galvanically isolated, protected against polarity switch and voltage transients.

To obtain a detailed data sheet for this seismometer, please contact Gaiacode Headquarters

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

Call us

Read our


  • 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]