Skip to main content
U.S. flag

An official website of the United States government

September 22, 2022

Editor: In the public interest and in accordance with the Federal Aviation Administration regulations, the USGS is announcing this low-level airborne project. Your assistance in informing the local communities is appreciated. 

Northeastern Wash. — Scientists with the U.S. Geological Survey and the Washington Geological Survey are partnering to image geology using airborne geophysical technology as part of the USGS Earth Mapping Resource Initiative (Earth MRI) project.

Flights will begin on/around Sept. 23, 2022, and continue through November until winter weather impacts safe aircraft operation and data quality. If needed, the data collection will resume in June or July of 2023 when weather is again favorable for surveying. Flights will be based out of assorted regional airports.   

The USGS is contracting with Precision GeoSurveys and EDCON-PRJ to collect the data in 11 northeast Washington counties, including Pend Oreille, Stevens, Ferry, Okanogan, Spokane, Lincoln, Grant, Douglas, Chelan, Skagit and Whatcom.  

Data collected as part of the survey is part of a national-scale effort to acquire modern high-resolution airborne magnetic and radiometric data. The survey will replace existing low-quality geophysical data, collected mostly in the 1980s, that is of limited use for geologic mapping. 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 several miles below the surface. The 3D models and maps produced from the survey will help understand the distribution of groundwater, 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 Washington Geological Survey scientists to guide more detailed geologic mapping at local scales.  

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.  

Image: Low-Flying Helicopter
Helicopter with magnetometer mounted in stinger.    

One AS350 helicopter will be actively collecting data in different parts of the survey area. The helicopter will be mounted with passive sensors that measure variations in the Earth’s natural magnetic field created by different rock types up to several miles beneath the surface. The magnetic sensor will be inside a skid-mounted stinger off the front of the aircraft. The helicopter will also include sensors inside the aircraft that measure soil and rock chemistry at the surface. 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 northeastern Wash. survey will be flown at elevations approximately 80 to 300 meters, or about 260 to 1000 feet, above ground in a grid pattern along east-west flight lines spaced approximately 200 meters, or approximately 650 feet, apart. North-south flight lines will be spaced 2000 meters, or 6500 feet, apart. All survey flights will occur during daylight hours. 

Image shows a map of Washington State with the area of survey marked
The area surveyed by Earth MRI in Washington State. The blue polygon is the base survey interest area. The yellow lines (transects A and B) are transects focused in deep river channels not part of the regular traverse and tie line grid. Transect A is roughly 95 km in length and Transect B roughly 105 km. The white transparent polygons are the Confederated Tribes of the Colville, Kalispel, and Spokane Indian Reservations. Areas in light purple are Fish and Wildlife Service special interest areas, such as wildlife refuges. Note the small cutout in the base polygon located to the southwest of the FWS special interest area and Kalispel reservation.