Designed and handmade in Switzerland, arolla broadband seismometer is the culmination of years of experience designing high precision, low noise, and reliable seismic equipment.
arolla’s versatile, compact, lightweight, and rugged design, make it an ideal choice for many applications and use cases.
From the beginning, the design goals for the arolla broadband seismometer were to make the most accurate, most reliable, easy to use/deploy, and consistent quality sensor on the market. Its triaxial design, wide temperature range, low temperature sensitivity, magnetic shielding, precision factory calibration of the sensor response, and robustness help to achieve these goals and beyond.
The introduction of arolla marks the launch of a new series of seismometers by GeoSIG, which will be complemented with further exciting products.
arolla will also be available in a posthole version.
Typical applications include study of local, regional, and teleseismic events; national seismic networks; Earth mode observations; site surveys; and more.
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Technology
- Feedback:
- Electromagnetic force balance with capacitive transducer
- Topology:
- Orthogonal triaxial X, Y, Z
- Mass centering:
- Automatic at power-up
Automatic or manual during operation;
Can be remotely initiated
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Performance
- Sensitivity:
- 1’200 V/m/s ±0.5% factory trimmed
- Self Noise:
- Typically below NLNM from 35 sec to 10 Hz and
within 3 dB of NLNM at 120 sec
See plot
- Bandwidth:
- 120 sec (0.00833 Hz) to 50 Hz
- Cross axis:
- ≤ 1% coupling; Including misalignment from axis to case reference
- Clip level:
- 17 mm/s up to 1 Hz
- Temperature:
- No re-centering required within ±45 °C
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Power Supply
- Type:
- Isolated 9 to 36 VDC
- Consumption:
- <1 W typical at 12 VDC
- Protection:
- Over voltage, reverse voltage, ESD, complies with EMC CE
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Interface
- Connector:
- Single 24 pin Milspec hermetic, isolated
- Output X, Y, Z:
- Velocity; 40 Vpp differential
Mass position; 10 Vpp single ended
- Calibration:
- Single ended with independent calibration coil,
can inject sinus signal, via cal_enable and cal_signal;
Can be remotely initiated
- Serial:
- RS485
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Physical & Environmental
- Material:
- Lightweight aluminium and rigid stainless steel construction
- Diameter:
- 235 mm
- Height:
- 283 mm incl. feet & handle
- Weight:
- < 10 kg (< 9.8 liter)
- Ingress:
- IP68 and NEMA6P;
Survives brief periods of submersion to 1m depth
- Operating temp:
- -20 to 60 °C
- Humidity:
- 0 to 100% non-condensing
- Shock:
- MIL STD 810G - 516.6 - Shock (air transport)
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Installation
- Maximum tilt:
- ± 2°
- Orientation:
- Floor mount with bubble level,
leveling spiked-feet with lock,
N-S indicator with groove
**Specifications subject to change without notice
- Precision calibration of sensor response
- Flat response from 120 seconds to 50 Hz
- Automatic leveling and mass centering; remote mass centering available
- No mass locking needed
- Electromagnetic shielding
- Corrosion resistant and robust housing
- Output sensitivity of 1200 V/m/sec
