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On the estimation of the structural index from low-pass filtered magnetic data
- Source :
- GEOPHYSICS. 79:J67-J80
- Publication Year :
- 2014
- Publisher :
- Society of Exploration Geophysicists, 2014.
-
Abstract
- The estimation of the structural index and of the depth to the source is the main task of many popular methods used to analyze potential field data, such as Euler deconvolution. However, these estimates are unstable even in the presence of a weak amount of noise, and Euler deconvolution of noisy data leads to an underestimation of structural index and depth. We have studied how the structural index and depth estimates are affected by applying low-pass filtering to the data. Physically based low-pass filters, such as upward continuation and integration, have been shown to be the best choice over a range of altitudes (upward continuation) or orders (integration filters), mainly because their outputs have a well-defined physical meaning. In contrast, mathematical low-pass filters require that the filter parameters be tuned carefully by means of several trial tests to produce optimally smoothed fields. The C-norm criterion is a reliable strategy to produce a stabilized vertical derivative, and we discourage Butterworth filters because they tend to a vertical integral filter, for a high cutoff wavenumber, thus complicating the interpretation of the estimated structural index. We found that the estimated structural index and depth to source increase proportionally with the amount of smoothing, unless in the case of overfiltering. In that case, the severe distortion of the original field may cause a decrease of the estimated structural index and depth to source.
- Subjects :
- Estimation
low-pass filter
Noise (signal processing)
Low-pass filter
Contrast (statistics)
Structural index
Filter (signal processing)
Geophysics
Euler deconvolution
Geochemistry and Petrology
Control theory
Range (statistics)
Upward continuation
Algorithm
Potential field interpretation
Mathematics
Subjects
Details
- ISSN :
- 19422156 and 00168033
- Volume :
- 79
- Database :
- OpenAIRE
- Journal :
- GEOPHYSICS
- Accession number :
- edsair.doi.dedup.....ba1f2e6ceba96a8015f6b35e63dac9ad