scholarly journals Final report [The 15th Workshop on Electromagnetic Induction in the Earth, held 8/20-26/2000, and The 5th Magnetotelluric Data Interpretation Workshop, 8/17-19/2000]

2002 ◽  
Author(s):  
David L Alumbaugh
Keyword(s):  
Electromagnetic Induction ◽  
Data Interpretation ◽  
Final Report ◽  
Magnetotelluric Data ◽  
The Earth

Spatial averaging of the vertical magnetic field in central‐loop configuration

Geophysics ◽  
1993 ◽  
Vol 58 (10) ◽  
pp. 1507-1510 ◽  
Author(s):  
Wei Qian ◽  
Laust B. Pedersen
Keyword(s):  
Tensor Decomposition ◽  
Data Interpretation ◽  
Impedance Tensor ◽  
Logarithmic Scale ◽  
Resistivity Structure ◽  
One Dimensional ◽  
Transient Electromagnetic ◽  
The Earth ◽  
Band Limited ◽  
Central Loop

Local resistivity heterogeneities can cause static shifts in the magnetotelluric (MT) impedance tensor that severely complicate data interpretation; the apparent resistivity is shifted on a logarithmic scale across the recorded frequency range while the phase has a band‐limited response. Different techniques such as electromagnetic array profiling (EMAP) (Torres‐Verdín and Bostick, 1992) and tensor decomposition (Zhang et al., 1987; Groom and Bailey, 1989; 1991) have been developed in the MT community to recognize and remove static shifts. Sternberg, et al. (1988) and Pellerin and Hohmann (1990) suggest that central‐loop transient electromagnetic (TEM) soundings can obtain an unbiased estimate of the regional resistivity structure of the earth and thereby correct for magnetotelluric static shifts. The regional resistivity structure of the earth must be one‐dimensional (1-D) for this method to work well.

scholarly journals Special issue “Studies on electromagnetic induction in the earth: recent advances”

2018 ◽  
Vol 70 (1) ◽  
Author(s):  
Weerachai Siripunvaraporn ◽  
Paul A. Bedrosian ◽  
Yuguo Li ◽  
Prasanta K. Patro ◽  
Klaus Spitzer ◽  
...  
Keyword(s):  
Electromagnetic Induction ◽  
Special Issue ◽  
The Earth ◽  
Recent Advances

COHERENCE FUNCTIONS FOR MAGNETOTELLURIC ANALYSIS

Geophysics ◽  
1974 ◽  
Vol 39 (3) ◽  
pp. 312-320 ◽  
Author(s):  
I. K. Reddy ◽  
D. Rankin
Keyword(s):  
Data Analysis ◽  
Linear System ◽  
System Approach ◽  
Partial Coherence ◽  
Impedance Method ◽  
Two Dimensional ◽  
Magnetotelluric Data ◽  
The Earth ◽  
Principal Axes ◽  
Tensor Impedance

A multiinput linear system approach is used to study the magnetotelluric phenomena in the presence of lateral conductivity inhomogeneities in the earth. The three types of coherence functions (ordinary, multiple, and partial) are defined, and their use in magnetotelluric data analysis is illustrated with a field example. Partial coherence functions are used to determine the principal axes in the case of two‐dimensional type inhomogeneities, and as measures of three‐dimensionality in the case of non‐two‐dimensional type structures. The results obtained using coherence functions are compared with those obtained with the conventional tensor impedance method.

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