Imaging of Ground Ice with Surface-Based Geophysics
ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
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Electrical properties of earth materials have profound differences due to the phase change of water to ice. This contrast is useful when using electro-magnetic methods to study permafrost terrains where frozen and thawed materials are intermixed. Engineering and science are in need of efficient, non-invasive tools for imaging ice and sediment composition. Borehole information is often used to map ice in permafrost terrains but it is time consuming, expensive, and can lead to over- or underquantification of ground ice. Advances in computing power have led to refined surface-based geophysical methods, and the goal of this study was to determine if the latest commercial technologies or system were promising for imaging ground ice and associated features and to compare the results across a variety of permafrost terrains. Electrical Resistivity Tomography ERT, in particular, has been effective for imaging ground ice. ERT measures the ability of materials to conduct or resist an electric current. A variation of this method, capacitive coupled resistivity CCR offers the ability for continuous data collection while moving across the landscape at scales of meters to kilometers. This greatly enhances the cost efficiency, applicability, and overall usefulness of the techniques and provides the ability to view variations in permafrost ice content on these larger scales.
- Geology, Geochemistry and Mineralogy
- Snow, Ice and Permafrost
- Electricity and Magnetism