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Water-borne electromagnetic induction data collected at Hen Cove, Pocasset, Massachusetts, 2022

Published by U.S. Geological Survey | Department of the Interior | Metadata Last Checked: January 27, 2026 | Last Modified: 2025-02-03T00:00:00Z
The bulk electrical conductivity of the subsurface was indirectly measured with electromagnetic imaging (EMI) by using induced secondary electromagnetic signals generated by subsurface electrical conductors in response to transmitted electromagnetic energy (Zohdy and others, 1974). Electromagnetic induction data were collected using a DUALEM-421 (DualEM, Inc.) mounted on an inflatable stand-up paddle board about 15 centimeters above the water surface. The DUALEM-421 uses 3 transmitter-receiver coil spacings (4-, 2-, and 1-meters) and 2 orientations (vertical dipole, and horizontal dipole). Larger coil spacings interrogate a larger/deeper sampling volume than smaller coil separations. REFERENCE: U.S. Geological Survey, Techniques of Water-Resources Investigations, Book 2, Chapter D1, Zhody, A. A. R., Eaton , G. P., and Mabey, D. R. https://doi.org/10.3133/twri02D1

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