Robust M-Estimation of Magnetotelluric Impedance Tensors

Sutarno, Doddy; Vozoff, K.

doi:10.1071/eg989383

Cited by 44 publications

(19 citation statements)

References 1 publication

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“…The superiority of the robust impedance estimation procedures over the conventional procedures (which are based on LS) was demonstrated by Jones et al (1989), Chave and Thomson (1989), and Sutarno and Vozoff (1989). Using synthetic and real data, Sutarno and Vozoff (1989) showed that the robust procedures always yield impedance estimates which are better than the conventional estimates.…”

Section: Phase Smoothed Robust Impedance Estimationmentioning

confidence: 93%

“…Using synthetic and real data, Sutarno and Vozoff (1989) showed that the robust procedures always yield impedance estimates which are better than the conventional estimates. However, since the underlying procedures are essentially based on the sort of model assumption that is intrinsic to the transfer function approach (that noise is restricted to the output), the procedures still need to employ the remote reference (RR) technique of Gamble et al (1979) in order to minimize the bias effect caused by noise in the input.…”

Section: Phase Smoothed Robust Impedance Estimationmentioning

confidence: 96%

“…The new robust procedure proposed here, incorporates phase smoothing in the regression M -estimation, The procedure is essentially an iteratively reweighted least-squares approach, which is similar to the one proposed by Sutarno and Vozoff (1989). Likewise, the procedure uses a complex framework.…”

Section: Phase Smoothed Robust Impedance Estimationmentioning

confidence: 98%

“…The data are very highly contaminated with common noise at the two locations. It was indicated that a hydroelectric dam and aluminum refinery which exist in this area were responsible for the noise (Sutarno and Vozoff, 1989). The impedance function example was computed for site 101 using site 102 horizontal magnetic field as a reference.…”

Section: Phase Smoothed Robust Impedance Estimationmentioning

confidence: 98%

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Phase‐smoothed robust M-estimation of magnetotelluric impedance functions

Sutarno

Vozoff

1991

GEOPHYSICS

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Accurate estimation of impedance functions is essential for the correct interpretation of magnetotelluric (MT) measurements. Noise is inevitably encountered when MT observations are conducted and, consequently, impedance estimates are usually based on least-squares (LS) regression. Least squares ultimately assumes simple Gaussian statistics. However, estimation procedures based on LS would not be statistically optimal, as outliers (abnormal data) are frequently superimposed on a normal ambient MT noise field which is approximately Gaussian. In this situation, the estimation can be seriously misleading.An alternative method for making unbiased robust estimates of MT impedance functions is based on regression M-estimation and the Hilbert Transform, operating on minimum-phase MT impedance functions. In the resulting regression estimates, outlier contamination is removed and other departures from Gauss-Markov optimality are not critical. Using MT data from the Columbia River Plateau and the EMSLAB Lincoln line, it is shown that the method can produce usable MT impedance functions even under conditions of severe noise contamination and in the absence of remote reference data.

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Section: Phase Smoothed Robust Impedance Estimationmentioning

confidence: 93%

Section: Phase Smoothed Robust Impedance Estimationmentioning

confidence: 96%

Section: Phase Smoothed Robust Impedance Estimationmentioning

confidence: 98%

Section: Phase Smoothed Robust Impedance Estimationmentioning

confidence: 98%

See 2 more Smart Citations

Phase‐smoothed robust M-estimation of magnetotelluric impedance functions

Sutarno

Vozoff

1991

GEOPHYSICS

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“…The use of robust statistical methods for the estimation of geomagnetic transfer functions has been discussed in Egbert and Booker (1986) . and EM noise rejection has been described previously in Strack et al (1989), Sutarno and Vozoff (1989), and Strack (1992). In the present application, special emphasis has been placed on developing an algorithm to be implemented in a microprocessor to carry out the noise rejection in real time.…”

Section: Introductionmentioning

confidence: 99%

Robust statistical methods for reducing sferics noise contaminating transient electromagnetic measurements

Buselli

Cameron

1996

GEOPHYSICS

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The transient electromagnetic (TEM) method is used extensively for mineral exploration and other applications such as geothermal soundings, oil exploration, groundwater pollution, soil salinity and geological mapping. Sferics pulses produced by lightning strokes propagating in the ionosphere-earth waveguide cavity induce noise in a bandwidth of a few Hz to tens of kHz. The usual method of stacking and calculating the mean of a given stack cannot effectively reduce the spike-like noise induced by high-amplitude sferics pulses. To reduce this type of noise, a number of different ways of stacking data were investigated and compared. Noise data were stacked by using robust estimators such as the median, trimmed mean, and a range of M-estimators. Since storage of all the samples of a given stack can take up a prohibitively large amount of microprocessor memory, recursive algorithms for the M-estimators and their standard error were developed for the realtime reduction of sferics pulses. The recursive algorithms have been demonstrated to work effectively on windowed data, and thus the memory normally required to obtain the mean is sufficient for calculation of the Mestimate.

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Robust Estimation Method of Sea Magnetotelluric Impedance Based On Correlative Coefficient

Liu¹,

Yan²,

He³

et al. 2003

Chinese J of Geophysics

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For the sea environment, traditional impedance estimation does not work well. A new robust method based on correlative coefficient is proposed in this paper. Normalization impedance and correct weight of Robust by correlative coefficient, theoretical modeling and field data show that our method can remove noise better than others. For the case the N/S is low 30%, though traditional and new impedance estimation can work well, new method is of low error. When the N/S is over 50%, the new method works much better than the traditional estimation and the regular robust method.

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Robust M-Estimation of Magnetotelluric Impedance Tensors

Cited by 44 publications

References 1 publication

Phase‐smoothed robust M-estimation of magnetotelluric impedance functions

Phase‐smoothed robust M-estimation of magnetotelluric impedance functions

Robust statistical methods for reducing sferics noise contaminating transient electromagnetic measurements

Robust Estimation Method of Sea Magnetotelluric Impedance Based On Correlative Coefficient

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