Astronomy and Astrophysics – Astronomy
Scientific paper
May 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000geoji.141..321w&link_type=abstract
Geophysical Journal International, Volume 141, Issue 2, pp. 321-336.
Astronomy and Astrophysics
Astronomy
20
Electromagnetic Induction, Impedance Tensor, Invariants, Magnetotellurics, Skew
Scientific paper
The magnetotelluric impedance tensor is defined in terms of seven independent parameters that are invariant under a rotation of the horizontal axes on the surface of the Earth, plus an angle that defines the orientation of the axes of reference. The invariants are algebraically related to but nevertheless different from those recently proposed by Szarka & Menvielle (1997). They have been chosen in such a way as to have clear representations on a Mohr circle diagram and also to reveal geoelectric properties of the Earth near the site where the impedance data are measured. The first two invariants define the properties of a 1-D earth when the next four invariants are negligibly small. If the next two are also non-negligible, the earth is 2-D with a strike direction that can be recovered. The last three invariants indicate different degrees of three-dimensionality and the discussion of them with reference to small-scale galvanic distortion in an otherwise 1- or 2-D structure largely retraces the insightful pioneering work of Bahr (1988). The properties of the invariants are illustrated with numerical calculations for a synthetic model consisting of a small conductive anomaly in the form of a cube at the surface of an otherwise 2-D earth that is divided by a vertical fault into regions with a strong resistivity contrast. Results are presented for synthetic data that contain only numerical noise, and for data to which 2 per cent random Gaussian noise has been added. The theoretical properties of the invariants are verified by the pure numerical data, and are confirmed statistically by the noisy data.
Agarwal A. K.
Lilley E. M. F.
Weaver J. T.
No associations
LandOfFree
Characterization of the magnetotelluric tensor in terms of its invariants does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Characterization of the magnetotelluric tensor in terms of its invariants, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Characterization of the magnetotelluric tensor in terms of its invariants will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1129293