Product Category
Gravimeters
Relative and absolute gravimeters from Scintrex, Micro-g LaCoste, and ZLS Corporation, for gravity surveys, microgravity monitoring, geodesy, and mineral and hydrocarbon exploration. Available New, Refurbished, Absolute Certified, or Surplus.
What is a Gravimeter?
A gravimeter measures the local strength of Earth's gravitational field, typically expressed in milligal (mGal) or microgal (µGal). Because gravity varies with subsurface density — denser rock (such as ore bodies or basement highs) produces a slightly stronger local field, while low-density material (such as salt domes, voids, or sediment basins) produces a slightly weaker one — a gravity survey maps these tiny variations to infer subsurface structure and density distribution.
A note on terminology: "absolute gravimeter" below refers to an instrument type — one that measures the true, absolute value of gravitational acceleration directly, as opposed to a "relative gravimeter" which measures differences in gravity between stations. This is unrelated to our Absolute Certified condition tier (described further down this page), which refers to the inspection and calibration standard we apply to used equipment, regardless of instrument type.
Relative vs. Absolute Gravimeters
- Relative gravimeters: Use a precision spring or fused-quartz elastic system suspending a test mass; the deflection of the mass under gravity is measured and referenced back to a known base station to derive gravity differences between survey points. Fast to operate (readings in under a minute), portable, and the standard tool for exploration and land-survey gravimetry. Typical field repeatability is in the low single-digit microgal to low milligal range depending on instrument grade.
- Absolute gravimeters: Measure gravitational acceleration directly by timing the free-fall of a test mass (a retroreflector) in a vacuum chamber using laser interferometry, with no reference to any other station. Absolute gravimeters achieve microgal-level accuracy and are used to establish gravity reference networks, calibrate relative instruments, and monitor long-term geodynamic changes (volcanic inflation, groundwater storage, post-glacial rebound, subsidence).
Applications & Considerations
Relative gravimeters are used extensively in mineral and hydrocarbon exploration (identifying density contrasts associated with ore bodies, salt structures, and basement topography), microgravity surveys (void and cavity detection, archaeology, dam and levee integrity), and geodesy. Absolute gravimeters are primarily used by national geodetic agencies, volcano observatories, and research institutions for high-precision reference measurements and time-lapse monitoring. Key specifications include reading precision and repeatability, drift rate, tare (shock) sensitivity, and — for field relative meters — the automated tilt and temperature compensation that keeps repeat readings consistent across a long survey day.
Gravimeter Brands We Supply
| Brand | Origin / Parent | Known For | Typical Application |
|---|---|---|---|
| Scintrex | Independent (Canada) | Relative gravimeters (autograv-type) with automated tilt/temperature compensation | Exploration, microgravity, land survey |
| Micro-g LaCoste | Independent (USA) | Absolute gravimeters using free-fall laser interferometry; also relative land & borehole meters | Geodesy, reference networks, monitoring |
| ZLS Corporation | Independent (USA) | Relative and marine/dynamic gravimeters for shipborne and airborne gravity surveys | Marine & airborne exploration |
Condition Tiers for Gravimeters
Factory New
Direct from the manufacturer, factory-calibrated, with full OEM warranty and original repeatability/drift specification sheet.
Refurbished
Sensor housing, electronics, and case inspected; battery and seals replaced; repeat-reading drift test performed before dispatch.
Absolute Certified
Full bench inspection with multi-day repeatability and drift verification against a reference station, calibration certificate issued at handover.
Surplus
Decommissioned survey-company inventory, sold functional and as-is — commonly sourced for spare sensors and accessories.
Frequently Asked Questions
What's the difference between an "absolute gravimeter" and your "Absolute Certified" tier?
They're unrelated terms that happen to share a word. An absolute gravimeter is an instrument type that measures true gravitational acceleration via free-fall interferometry, as opposed to a relative gravimeter which measures differences between stations. Our Absolute Certified tier is a condition/quality grade we apply to used equipment of any type — it means the unit has been fully bench-inspected and recalibrated against a traceable reference before sale. A relative gravimeter can be sold as Absolute Certified; an absolute (free-fall) gravimeter can also be sold New, Refurbished, or Surplus.
How accurate is a refurbished relative gravimeter compared to new?
Well-maintained relative gravimeters hold their factory precision for many years, since the core sensing element (a fused-quartz or metal spring system) sees very little wear under normal field use. Our Refurbished units are drift-tested over a repeat-reading cycle, and Absolute Certified units are additionally verified against a known reference station, so buyers can expect performance close to original specification in both tiers.
Can you supply gravimeters for marine or airborne survey work?
Yes — ZLS Corporation and similar dynamic/marine gravimeter systems designed for gyro-stabilized shipborne and airborne platforms are available across our condition tiers. Land-survey relative gravimeters (Scintrex-type) are not directly interchangeable with marine systems, so let us know your platform when requesting a quote.