Electromagnetic induction by a finite electric dipole source over a 2-D earth

Journal Article · Mon Feb 01 00:00:00 EST 1993 · Geophysics; (United States)

DOI:https://doi.org/10.1190/1.1443406· OSTI ID:5999808

Unsworth, M J ^[1]; Travis, B J ^[2]; Chave, A D ^[3]

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1. Univ. of British Columbia, Vancouver, BC (Canada)
2. Los Alamos National Lab., NM (United States)
3. Woods Hole Oceanographic Institution, MA (United States)

A numerical solution for the frequency domain electromagnetic response of a two-dimensional (2-D) conductivity structure to excitation by a three-dimensional (3-D) current source has been developed. The fields are Fourier transformed in the invariant conductivity direction and then expressed in a variational form. At each of a set of discrete spatial wavenumbers a finite-element method is used to obtain a solution for the secondary electromagnetic fields. The finite element uses exponential elements to efficiently model the fields in the far-field. In combination with an iterative solution for the along-strike electromagnetic fields, this produces a considerable reduction in computation costs. The numerical solutions for a horizontal electric dipole are computed and shown to agree with closed form expressions and to converge with respect to the parameterization. Finally some simple examples of the electromagnetic fields produced by horizontal electric dipole sources at both the sea floor and air-earth interface are presented to illustrate the usefulness of the code.

• OSTI ID: 5999808
• Journal Information: Geophysics; (United States), Vol. 58:2; ISSN 0016-8033
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CONTINENTAL MARGIN
ELECTROMAGNETIC SURVEYS
DATA ANALYSIS
ELECTRIC DIPOLES
ELECTROMAGNETIC FIELDS
ELECTROMAGNETIC RADIATION
FOURIER TRANSFORMATION
NUMERICAL SOLUTION
RESPONSE FUNCTIONS
SEA BED
TWO-DIMENSIONAL CALCULATIONS
DIPOLES
ELECTRICAL SURVEYS
FUNCTIONS
GEOPHYSICAL SURVEYS
INTEGRAL TRANSFORMATIONS
MULTIPOLES
RADIATIONS
SURVEYS
TRANSFORMATIONS
580000* - Geosciences