Publication 155
The inability of magnetotelluric off-diagonal impedance tensor elements to sense oblique conductors in 3-D inversion
Kiyan, D., A.G. Jones, and J. Vozar
Abstract
The advantages of modelling single profile magnetotelluric (MT) data with three-
dimensional (3-D) inversion have previously been shown, both with a synthetic data
set and field data set. In this paper, we use synthetic data sets from a North-South
oriented prfile to demonstrate the importance of aligning the 3-D mesh and data
coordinate system with the dominant geo-electrical strike direction in 3-D inverse
modelling. The resistivity model investigated consists of a regional, 45 degrees east of
north elongated 2-D conductive structure. We compare the results of full impedance
tensor inversion with the results from inversion of only off-diagonal components of
the MT impedance tensor. The 3-D inversion result obtained with the complete
tensor elements yields the subsurface model closest to the original model, whereas
the result of inverting only off-diagonal components is the poor imaging of the
continuity of the conductive 2-D body. However, the conductor can be correctly
recovered using only the off-diagonal components if the model mesh and the data
are aligned with quasi-2-D geo-electrical strike.
Source
Geophysical Journal International, 196, 1351–1364, doi:10.1093/gji/ggt470.
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Alan G Jones / 14 February 2014 /
alan-at-cp.dias.ie