none
10.1190/1.1442813
Society of Exploration Geophysicists
Society of Exploration Geophysicists
186
4723762
5981
2020101514400900239
10.1190
20201015T21:40:27Z
20021011T19:40:18Z
1069
GEOPHYSICS
GEOPHYSICS
00168033
19422156
12
1990
55
12
Occam’s inversion to generate smooth, two‐dimensional models from magnetotelluric data
C.
deGroot‐Hedlin
Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, A025, La Jolla, CA 92093
S.
Constable
Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, A025, La Jolla, CA 92093
Magnetotelluric (MT) data are inverted for smooth 2D models using an extension of the existing 1D algorithm, Occam’s inversion. Since an MT data set consists of a finite number of imprecise data, an infinity of solutions to the inverse problem exists. Fitting field or synthetic electromagnetic data as closely as possible results in theoretical models with a maximum amount of roughness, or structure. However, by relaxing the misfit criterion only a small amount, models which are maximally smooth may be generated. Smooth models are less likely to result in overinterpretation of the data and reflect the true resolving power of the MT method. The models are composed of a large number of rectangular prisms, each having a constant conductivity. [Formula: see text] information, in the form of boundary locations only or both boundary locations and conductivity, may be included, providing a powerful tool for improving the resolving power of the data. Joint inversion of TE and TM synthetic data generated from known models allows comparison of smooth models with the true structure. In most cases, smoothed versions of the true structure may be recovered in 12–16 iterations. However, resistive features with a size comparable to depth of burial are poorly resolved. Real MT data present problems of non‐Gaussian data errors, the breakdown of the two‐dimensionality assumption and the large number of data in broadband soundings; nevertheless, real data can be inverted using the algorithm.
12
1990
1613
1624
10.1190/1.1442813
10.1190/1.1442813
https://library.seg.org/doi/10.1190/1.1442813

https://library.seg.org/doi/pdf/10.1190/1.1442813

http://geophysics.geoscienceworld.org/cgi/doi/10.1190/1.1442813