Geophysical studies for geological mapping related to water resources typically use seismic refraction, seismic reflection, electromagnetic induction (EM), or electrical resistivity methods. The main goal of the program is to assist with geologic mapping of potential aquifers by providing information between and beyond existing well data. Geophysical studies are also used to locate buried artifacts and/or waste material. For example, they can be used to find buried drums or other metal at hazardous waste sites. They can also help in archeological studies. Typically, EM and magnetic methods are used for these applications.
Geophysical mapping is done in conjunction with geological mapping and test drilling. Program staff members work cooperatively with the Ground Water Technical Analysis Program, the Observation Well Program, and the Ground Water Mapping Program to support DNR mapping efforts. Program staff also conduct geophysical field studies for cooperative projects with other government agencies, most typically with the Minnesota Geological Survey (MGS) and the U.S. Geological Survey-Water Resources Division (USGS-WRD).
Geophysics data is available on request.
The map shows a plot of seismic refraction and resistivity imaging data collected by the County Geologic Atlas program.
- The seismic refraction lines usually show the ground surface, the interpreted top of the water table and first bedrock unit.
- The resistivity imaging lines show interpreted resistivity values along each line versus depth.
Groundwater Exploration Using Geophysical Methods
- Hydrogeology of the Rock River Watershed, Minnesota and Associated Off-Channel Habitats of the Topeka Shiner, April 2004
- Yellow Medicine County, January 2000 (816KB)
- Worthingon Area, January 2000 (1.67MB)
- Resistivity imaging of gravel deposits at Bicentennial Prairie, Clay County, Minnesota (635k)
- Seismic Refraction Velocities in Minnesota (42KB)
- Resistivity imaging of karst geology at Mystery Cave State Park, Fillmore County, Minnesota (1.2MB)
- Todd Petersen, Program Manager, 651-259-5698