Analogue Earthquake & Vibration Sensors

We have been using different types of sensors in our Gecko recorders to make all-in-one seismographs and accelerographs, but sometimes it is more convenient to have a sensor located in a different location to your recorder.

We are now offering split systems with a range of seismometers and accelerometers for connection to a Gecko recorder.

Seismometers

Our portable triaxial velocity range takes the sensors from inside the Gecko Blast, Gecko Tremor, and Gecko Prism models and places them in a range of external casings for remote sensing applications.

GEO-2F: a surface-mounted compact 2Hz triaxial geophone for low frequency blast monitoring and high frequency survey applications.	[bg_collapse view=”button-green” color=”#4a4949″ icon=”arrow” expand_text=”GEO-2F Details” collapse_text=”Hide Details” ]GEO-2F is our newest compact 2Hz geophone as used in the Gecko Force. It comes with a 2m cable as standard, but special orders can be manufactured with up to 200m of cable fitted. It includes a mounting plate with removable spikes for soil installation.[/bg_collapse]
GEO-5F: a surface-mounted 4.5Hz triaxial geophone for urban vibration monitoring and high frequency survey applications.	[bg_collapse view=”button-green” color=”#4a4949″ icon=”arrow” expand_text=”GEO-5F Details” collapse_text=”Hide Details” ]GEO-5F uses lower cost 4.5Hz geophones as in the Gecko Blast. 2m cable and mounting plate with spikes included.[/bg_collapse]
GEO-XF: an omnidirectional 14Hz triaxial geophone for close range high frequency surveys.	[bg_collapse view=”button-green” color=”#4a4949″ icon=”arrow” expand_text=”GEO-XF Details” collapse_text=”Hide Details” ]GEO-XF uses omnidirectional geophones which can be installed at any angle. 2m cable and mounting plate with spikes included.[/bg_collapse]
GEO-xB: a 56mm diameter borehole triaxial version of the above geophones, when you need to bury your sensor to minimise environmental noise.	[bg_collapse view=”button-green” color=”#4a4949″ icon=”arrow” expand_text=”GEO-xB Details” collapse_text=”Hide Details” ]GEO-2B, GEO-5B, or GEO-XB is a Ø56mm borehole cased version of the geophones from the GEO-xF cases. It comes fitted with a custom length of load-bearing kevlar-reinforced cable, up to 200m. GEO-2B and GEO-5B must be installed vertically, but GEO-XB can be installed at any angle.[/bg_collapse]
SPS-HS: high sensitivity passive geophones for local (500km range) earthquake monitoring or low frequency (2Hz) blast monitoring.	[bg_collapse view=”button-green” color=”#4a4949″ icon=”arrow” expand_text=”SPS-HS Details” collapse_text=”Hide Details” ]SPS-HS takes the Ø136mm base from the Gecko Tremor and adds a Gecko-style lid to seal in the unpowered passive sensors. This Short Period Seismometer comes with connector on the lid and a matching cable plug, optionally fitted with up to 50m of 3-pair cable. Use the sensor with a 40Vpp sensor for a range of ±254mm/s (10 in/sec) for monitoring vibrations in urban environments, or set the gain to x16 for local earthquake monitoring where greater sensitivity is required.[/bg_collapse]
SPS-HR: a short period seismometer (10s) with high range output to view low frequency signals from more distant earthquakes.	[bg_collapse view=”button-green” color=”#4a4949″ icon=”arrow” expand_text=”SPS-HR Details” collapse_text=”Hide Details” ]SPS-HR uses the same Ø136mm casing, but this time uses a version of the optical sensor technology from the Prism-SP to create a Short Period Seismometer with 10-second (0.1Hz) to 150Hz flat frequency response and 595V/m/s sensitivity over a High Range differential output of ±30V. [/bg_collapse]
MPS-HR: a middle period seismometer (40s) with high range output with a frequency range suited to regional-scale earthquake monitoring networks.	[bg_collapse view=”button-green” color=”#4a4949″ icon=”arrow” expand_text=”MPS-HR Details” collapse_text=”Hide Details” ]MPS-HR is the analogue sensor equivalent of the Prism-MP which uses a 40-second to 90Hz Middle Period Seismometer. Sensitivity is 750V/m/s, with a maximum output of ±30V (differential). From 2021 any matching Gecko recorder can be specified with ±20V (40Vpp) or ±30V (60Vpp) input range.[/bg_collapse]
LPS-HR: a long period seismometer (120s) with high range output and a frequency range is suited to global-scale earthquake monitoring networks.	[bg_collapse view=”button-green” color=”#4a4949″ icon=”arrow” expand_text=”LPS-HR Details” collapse_text=”Hide Details” ]LPS-HR is the analogue sensor equivalent of the Prism-LP which uses a 120-second to 60Hz Long Period Seismometer with the same 750V/m/s ±30V output as the MPS-HR.[/bg_collapse]

Accelerometers

Our triaxial acceleration range takes the sensors from inside the Gecko SMA variants and places them in a range of external casings. The best part is that all of our accelerometers are omnidirectional, meaning that they can be mounted at any angle without levelling. The choice between low cost accelerometers (LCA) and low frequency accelerometers (LFA) has never been easier.

LCA-2G: a low voltage output accelerometer with ±2g range	[bg_collapse view=”button-red” color=”#fffff” icon=”arrow” expand_text=”LCA-2G Details” collapse_text=”Hide Details” ]LCA-2G moves our low noise MEMS accelerometer block from inside the Gecko SMA-2G and places it in a small case that can be mounted to the floor, wall or ceiling. Gravity will offset the vertical component by 1g. This Low Cost Accelerometer comes with 1m of cable fitted, but can be specified with up to 50m of cable. Ideal for basic structural monitoring in low seismicity areas.[/bg_collapse]
LCA-5G: a low voltage output accelerometer with ±5g range	[bg_collapse view=”button-red” color=”#fffff” icon=”arrow” expand_text=”LCA-5G Details” collapse_text=”Hide Details” ]LCA-5G is just like the LCA-2G but uses the ±5g range sensors from the Gecko SMA-5G, meaning the vertical channel can record from -4g to +6g. Suited to structural monitoring in areas with strong earthquake activity. All LCA models have ±4V differential output, so we recommend setting your Gecko recorder to a gain of x4 to maximise data resolution.[/bg_collapse]
LCA-XG: a low voltage output accelerometer with ±10g range	[bg_collapse view=”button-red” color=”#fffff” icon=”arrow” expand_text=”LCA-XG Details” collapse_text=”Hide Details” ]LCA-XG is, as you may have guessed, a ±10g range MEMS accelerometer, suited to very near field strong ground motion monitoring (e.g. blasts measured within a mine). Higher range versions are available by special order, with maximum acceleration levels of ±25g, ±50g, ±100g, ±200g and ±400g.[/bg_collapse]
LFA-HR: a super-quiet, ±2g accelerometer with high voltage output	[bg_collapse view=”button-red” color=”#fffff” icon=”arrow” expand_text=”LFA-HR Details” collapse_text=”Hide Details” ]LFA-HR allows separation of the Gecko SMA-HR into sensor and recorder. With the high range ±30V output, the Low Frequency Accelerometer can show data from well below 1µg (1 millionth of the force of gravity) and is the most sensitive accelerometer in our range. It is able reveal the modal response of a structure even from small local earthquakes while recording motion up to twice the force of gravity. The central bolt hole in our Ø136mm casing allows you to bolt it down with a minimum of fuss to ensure your sensor stays attached to your structure when a strong earthquake strikes.[/bg_collapse]
LFA-XR: a very low noise, ±10g accelerometer, IEPE powered sensors	[bg_collapse view=”button-red” color=”#fffff” icon=”arrow” expand_text=”LFA-XR Details” collapse_text=”Hide Details” ]LFA-XR uses IEPE technology sensors from the CSIRO-developed Geosystems mine accelerometer that our company has been producing for over 20 years. It provides a wider ±10g range while maintaining good low noise, low frequency performance for advanced structural behaviour analysis. It also uses the Gecko’s Ø136mm base and new lid design.[/bg_collapse]
LFA-XB: a borehole version of the ±10g range LFA-XR accelerometer	[bg_collapse view=”button-red” color=”#fffff” icon=”arrow” expand_text=”LFA-XB Details” collapse_text=”Hide Details” ]LFA-XB is the original CSIRO-developed Geosystems mine accelerometer, a borehole version of the ±10g range LFA-XR. It uses the same Ø56mm casing as the GEO-HB and can be specified with hundreds of metres of load-bearing kevlar-reinforced cable. Being omnidirectional, tilt angle during installation does not affect range or response. Best suited for underground mines and foundation monitoring in dams, buildings, and other structures. [/bg_collapse]

-HR: What is High Range Output?

Our Gecko recorders have always had a standard input range of ±20V (40Vpp differential) for use with sensors from seismic sensor manufacturers. From 2021, Gecko can be internally switched to a ±30V (60Vpp) input range for use with our High Range (-HR) output sensors. All -HR sensors have a maximum output of ±30V (differential) and the included cable plug can be optionally fitted with up to 50m of 6-pair cable.

What are IEPE sensors?

The LFA-XR (and SMA-XR) use IEPE (Integrated Electronics Piezo-Electric) sensors, which require +25VDC and a constant 4mA current be fed across each channel wire pair, and a high pass filter to remove the offset bias voltage. This power supply is included as standard on the Gecko, but most other seismic recorders will require a signal conditioner to inject the required power. The sensors have a ±5V range output, so run your Gecko at a gain of x4 to maximise data resolution. If you only need a ±5g or ±2.5 range, use gains of x8 or x16 respectively.