tTEM processed survey data, Shellmound, Mississippi, March 2018

Publication Date

2020

Start Date

2018-03-27

End Date

2018-03-28

Eric A. White, Carole D. Johnson, Wade H. Kress, James R. RIgby, Jim H. Alvis, and John W. Lane, Jr, 2020, tTEM processed survey data, Shellmound, Mississippi, March 2018: U.S. Geological Survey.

Type: catalogItemUrl

Surface geophysical methods can provide information for the characterization of the subsurface structure of the earth for aquifer investigations. Towed- transient electromagnetic (tTEM) surveys provide resistivity soundings of the subsurface, which can be related to lithology and hydrogeology. In the towed-TEM method, electrical current is cycled through a wire in a transmitter loop (Tx), which in turn produces a static magnetic field. When the current is abruptly terminated, an instantaneous current is induced in the earth, and it moves downward and outward as the induced current decays with time. The decay is controlled by the resistivity of the earth. A receiver (Rx) towed behind the Tx loop in an offset configuration, measures the secondary magnetic field as a function of time (dB/dt). Decaying voltage measurements at the receiver are converted to apparent resistivity, which can be inverted to recover the depth-dependent resistivity structure of the earth.

• USGS Lower Mississippi-Gulf Water Science Center

Data source

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