Mapping ice-bonded permafrost with electrical methods in Sisimiut, West Greenland

• Main Author: Ingeman-Nielsen, Thomas
• Format: Article in Journal/Newspaper
• Language: English
• Published: EAGE Publications BV 2006
• Subjects: Arctic; Greenland; Ice; permafrost; Sisimiut
• Online Access: https://orbit.dtu.dk/en/publications/490f94c6-2e6c-4b8e-acce-5780f3613233

Permafrost delineation and thickness determination is of great importance in engineering related projects in arctic areas. In this paper, 2D geoelectrical measurements are applied and evaluated for permafrost mapping in an area in West Greenland. Multi-electrode resistivity profiles (MEP) have been collected and are compared with borehole information. It is shown that the permafrost thickness in this case is grossly overestimated by a factor of two to three. The difference between the inverted 2D resistivity sections and the borehole information is explained by macro-anisotropy due to the presence of horizontal ice-lenses in the frozen clay deposits. It is concluded that where the resistivity method perform well for lateral permafrost mapping, great care should be taken in evaluating permafrost thickness based on 2D resistivity profiles alone. Additional information from boreholes or other geophysical techniques is needed for correct interpretation.