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  • Article
  • Open Access

Regional geoelectrical complexity of the Western Canada Basin from magnetotelluric tensor invariants

  • 1Email author,
  • 1, 3,
  • 2,
  • 2,
  • 2 and
  • 1
Earth, Planets and Space201454:BF03352437

  • Received: 6 July 2001
  • Accepted: 29 July 2002
  • Published:


Magnetotelluric data from 323 sites in the Western Canada Basin have provided impedance tensors from which invariants based on Mohr circle analysis are calculated. From thresholds determined from an initial examination of the data, the invariant responses are used to explore the dimensionalities of subsurface structures. This leads to a classification of the electrical structure of the region with respect to dimensionality wherein zones with sites of similar nature are delineated, and demonstrates that the invariants can be used as a dimensionality indicator to infer regional geoelectrical complexity. It is observed that the dimensionality appears to increase with period and this result is consistent with the response from sounding a zone of increasing areal extent and may indicate more laterally complex structure at depth, but may also be due to fundamental limitations of galvanic distortion analysis.


  • Canada Basin
  • Tensor Element
  • Invariant Response
  • Magnetotelluric Data
  • Mohr Circle