Gaiacode - Model THETA Standard -Seismometer
Gaiacode's THETA Seismometer series integrates three innovative seismic sensors with a rectilinear suspension system for inertial masses, eliminating common issues found in pendulous designs and ensuring minimal spurious modes at higher frequencies. This configuration allows these seismometers to maintain a flat response to ground motion velocity from 120 seconds up to 150 Hz, with high cross-axis rejection capabilities. The system's connector turret is designed for accessibility and water resistance, following the IP68 standard. The THETA Standard model features classical orthogonal sensor topology, adjustable brass feet, and all non-magnetic components to reduce noise from external magnetic fields. The unit covers an operational tilt range of ±10 degrees and offers sensitivities between 2*750 to 2*5000 V/m/s. The device is powered within 9 to 36 Volt, consuming 490 mW at 12 V. The rugged enclosure, made from hard anodized aluminium, is engineered for durability, weighing 3.1 kg and dimensions of 13.8 cm by 18.5 cm.
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.
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.
Enclosure
- 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.