Gravity Method – A Last Resort in Critical Situations
Our professionals use the gravity method in difficult settings where faster and more economical methods cannot be used. This method is an unobtrusive tool used in environmentally sensitive areas, such as parking garages and building interiors. Gravity method surveys are most often used as a final resort and involve mapping underground washouts, sinkholes, voids, and other cavities.
Gravity has been used successfully when other strategies fail to find old USTs that were abandoned pre-construction and subsequently covered by building foundations. To measure the small spatial differences in Earth’s gravitational pull, we use an extremely sensitive instrument, the gravimeter, to detect gravitational anomalies less than one ten-millionth of Earth’s total gravitational field.
Gravity has been used successfully when other strategies fail to find old USTs that were abandoned pre-construction and subsequently covered by building foundations. To measure the small spatial differences in Earth’s gravitational pull, we use an extremely sensitive instrument, the gravimeter, to detect gravitational anomalies less than one ten-millionth of Earth’s total gravitational field.
How Does a Gravimeter Work?
Gravimeters do not measure the absolute value of gravity’s pull. Rather, they measure spatial differences in the pull—essentially, relative gravity. If the gravity field over an air-filled void (i.e., UST, tunnel, or cavern) is measured, and the void is close enough to the ground surface, a decrease in the gravitational pull across the void will be measured. Anomalies, including voids, and subsurface material distribution are determined from gravity data using non-linear least-squares inversion of the data. The computed models are then presented as contour maps.
We encourage you to contact us today for more details about the gravity method.
We encourage you to contact us today for more details about the gravity method.
