Gravity is the force that keeps us on the planet, and interferometric gravity gradiometry (IGG) is a method of measuring the subtle acceleration of gravity on the surface of the Earth in order to better understand its effects around us. This technology has been used in many areas of research, including geophysics, hydrology and geotechnical engineering.
The most common type of IGG is called gravity gradiometry, and it uses two or more gravity meters to measure gravity at a specific location. By comparing these readings with readings taken at other points near the same location, it can measure the subtle changes in gravity caused by variations in the subsurface of the Earth. This allows scientists to better understand how certain physical features, such as underground caves or magma chambers, affect the local gravity field and in turn, our environment.
Applications of IGG technology can be broken down into three main applications: exploration and mapping, environmental monitoring and engineering and geology applications.
Exploration and mapping applications are probably the most familiar to the public and concern the finding of underground resources such as oil salt, geothermal reservoirs and mineral deposits. The technology can be used to detect larger scale features such as mountain ranges, ocean basins, and subsurface impact structures. Scientists can also use gravity gradiometry to try to determine the thickness and nature of sedimentary basins and oceanic crust and the offset of major faults.
Environmental monitoring applications, using IGG, can track changes in the environment both on land and in the oceans. This can include landslides, sinkholes, subsidence of buildings, land subsidence resulting from natural causes or from excessive pumping of the water table and other environmental hazards.
In engineering and geology applications, IGG is used to better understand how natural geological features, such as faults, dykes, salt layers and water-filled cavities, can affect or be affected by human construction. For example, gravity data can be used to help determine the exact location and depth of shallow, low permeability deposits to reduce the risk of sinkholes and gas explosions.
Overall, Interferometric Gravity Gradiometry is a powerful tool for scientists to use in better understanding our environment, both on land and in the oceans. Its applications, from exploration and mapping to engineering and geology, offer a deeper insight into the changing nature of our world.
