Electromagnetic Induction Studies

Wannamaker, Philip E.; Hohmann, Gerald W.

doi:10.1002/rog.1991.29.s1.405

Cited by 16 publications

(14 citation statements)

References 352 publications

(196 reference statements)

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“…Low resistivity of broad regional extent (10's of ohm-m over 100's of km) due to released fluids in the deep crust is common in extending regimes (Wannamaker and Hohmann, 1991). In contrast, the low resistivity zone below the Byrd Basin is very weak and restricted laterally, so that quiescent conditions are implied (Bailey, 1990).…”

Section: Discussionmentioning

confidence: 97%

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Dormant state of rifting below the Byrd Subglacial Basin, West Antarctica, implied by magnetotelluric (MT) profiling

Wannamaker¹,

Stodt²,

Olsen³

1996

Geophysical Research Letters

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During the 1994–1995 austral summer field season, we collected twelve, high‐quality MT soundings over the Byrd Subglacial Basin of central West Antarctica (82°36′S lat., 118°14′W long, approx.) in the period range 0.01 s to 400 s. Ten equispaced sites in a 54 km profile cross regional aeromagnetic trends and complement seismic reflection and refraction results collected by others. Our purposes were to prove such measurements were feasible over the 2 km thick interior ice sheet, and to show from deep electrical resistivity whether the Byrd Basin comprises an active rift environment. The difficult acquisition of electric field data on ice was overcome using a custom electrometer system, with preamplifiers located at the electrode sites to buffer the high contact impedances of the ice as close to the source as possible. Two‐dimensional modeling of the profile shows that resistivity of the deep crust and upper mantle is about 2000–3000 ohm‐m to 100 km depth or more. This is much higher than observed in active extensional regimes, suggesting that the current state of rifting, at least in this part of central West Antarctica, is dormant.

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Section: Discussionmentioning

confidence: 97%

“…In contrast, the low resistivity zone below the Byrd Basin is very weak and restricted laterally, so that quiescent conditions are implied (Bailey, 1990). The dike-like structures of Figure 4 are more typical of non-thermal causes such as metasedimentary graphite or sulfides (Wannamaker and Hohmann, 1991).…”

Section: Discussionmentioning

confidence: 99%

Dormant state of rifting below the Byrd Subglacial Basin, West Antarctica, implied by magnetotelluric (MT) profiling

Wannamaker¹,

Stodt²,

Olsen³

1996

Geophysical Research Letters

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“…(For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) and a few percent partial melt concentrated near its upper levels (also see Wannamaker and Hohmann (1991)). …”

Section: Figmentioning

confidence: 96%

Electrical structure of the central Cascadia subduction zone: The EMSLAB Lincoln Line revisited

Evans

Wannamaker

McGary³

et al. 2014

Earth and Planetary Science Letters

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“…In their recent review, Wannamaker and Hohmann (1991) refer to a current revolution in electromagnetic induction studies. The magnetotelluric method has been central in this development, with data of increased precision observed over wide ranges of frequency.…”

Section: Discussionmentioning

confidence: 99%

Magnetotelluric analysis using Mohr circles

Lilley

1993

GEOPHYSICS

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The Mohr circle, most commonly met in the analysis of mechanical stress, is used to depict magnetotelluric impedance information, taking the real and quadrature parts of magnetotelluric tensors separately. The magnetotelluric concepts of two-dimensionality, three-dimensionality, skew and anisotropy are then all given quantitative expression on a diagram, as are various magnetotelluric invariants. In particular, a new invariant, the "central impedance," becomes evident in a discussion of effective impedances. Some insight is gained into impedance rotations, and an anisotropy angle is defined, analogous to skew angle.Mohr circles are also tested to depict the effects of the shear and twist operations on a regionally twodimensional structure. Generally, the application of shear or twist results in an impedance tensor with a Mohr circle of typical three-dimensional form.

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Electromagnetic Induction Studies

Cited by 16 publications

References 352 publications

Dormant state of rifting below the Byrd Subglacial Basin, West Antarctica, implied by magnetotelluric (MT) profiling

Dormant state of rifting below the Byrd Subglacial Basin, West Antarctica, implied by magnetotelluric (MT) profiling

Electrical structure of the central Cascadia subduction zone: The EMSLAB Lincoln Line revisited

Magnetotelluric analysis using Mohr circles

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