Earth MRI is a cooperative effort between the USGS, the Association of American State Geologists and other Federal, State and private sector organizations to improve our knowledge of the geologic framework in the United States.

The survey data will be collected using a helicopter and will fly over parts of Autauga, Bibb, Blount, Bullock, Calhoun, Chambers, Cherokee, Chilton, Clay, Cleburne, Coosa, Elmore, Etowah, Jefferson, Lee, Macon, Marshall, Randolph, Russell, St. Clair, Shelby, Talladega, Tallapoosa and Tuscaloosa Counties. Weather permitting, the survey will begin in mid-March 2023.

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Data collected as part of this Alabama survey is part of a national-scale effort to acquire modern high-resolution airborne electromagnetic data. The new geophysical survey will use the latest technological developments that will allow scientists to develop high-resolution three-dimensional representations of geology to depths over 1,000 feet below the surface. The 3D models and maps produced from the survey will help understand the distribution of ground-water, mineral and energy resources as well as the potential for natural hazards. Data collected as part of this effort will be made public and used by USGS in collaboration with scientists at the Geological Survey of Alabama to guide more detailed geologic mapping at local scales. 

The helicopter and towed equipment will fly along pre-planned flight paths relatively low to the ground at 100-200 feet above the surface. A sensor that resembles a large hula-hoop will be towed beneath the helicopter to measure small electromagnetic signals that can be used to map geologic features below Earth’s surface. Flight line separation will vary depending on location, typically separated by about 1,600 to 3,300 feet in detail survey areas or 3 miles in more regional survey areas. The USGS is contracting with Skytem under NV5 Geospatial to collect data.

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None of the instruments carried on the aircraft pose a health risk to people or animals. The aircraft will be flown by experienced pilots that are specially trained and approved for low-level flying. The company works with the FAA to ensure flights are safe and in accordance with U.S. law. The surveys will be conducted during daylight hours only. Surveys do not occur over- populated areas and the helicopter will not directly overfly buildings at low altitude.