Multiscale analysis of potential fields by a ridge consistency criterion: the reconstruction of the Bishop basement

Fedi, Maurizio; Florio, Giovanni; Cascone, Lorenzo

doi:10.1111/j.1365-246x.2011.05259.x

Cited by 37 publications

(22 citation statements)

References 25 publications

(39 reference statements)

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“…A criterion to assist in the ridge selection and choice was recently given (Fedi et al . ). However, with the multiridge Euler deconvolution proposed in this paper, we analyse many ridges of different types simultaneously, so that the task of correctly selecting the ridges is no longer so critical.…”

Section: Discussionmentioning

confidence: 97%

“…In fact, to be suitable, ridges must not be curved and even when linear, those related to the distal parts of the anomaly are the most affected by interference and noise and should be excluded from the interpretation process. A criterion to assist in the ridge selection and choice was recently given (Fedi et al 2012). However, with the multiridge Euler deconvolution proposed in this paper, we analyse many ridges of different types simultaneously, so that the task of correctly selecting the ridges is no longer so critical.…”

Section: O N C L U S I O N Smentioning

confidence: 99%

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Multiridge Euler deconvolution

Florio

Fedi

2013

Geophysical Prospecting

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Potential field interpretation can be carried out using multiscale methods. This class of methods analyses a multiscale data set, which is built by upward continuation of the original data to a number of altitudes conveniently chosen. Euler deconvolution can be cast into this multiscale environment by analysing data along ridges of potential fields, e.g., at those points along lines across scales where the field or its horizontal or vertical derivative respectively is zero. Previous work has shown that Euler equations are notably simplified along any of these ridges. Since a given anomaly may generate one or more ridges we describe in this paper how Euler deconvolution may be used to jointly invert data along all of them, so performing a multiridge Euler deconvolution. The method enjoys the stable and high-resolution properties of multiscale methods, due to the composite upward continuation/vertical differentiation filter used. Such a physically-based field transformation can have a positive effect on reducing both high-wavenumber noise and interference or regional field effects. Multiridge Euler deconvolution can also be applied to the modulus of an analytic signal, gravity/magnetic gradient tensor components or Hilbert transform components. The advantages of using multiridge Euler deconvolution compared to single ridge Euler deconvolution include improved solution clustering, increased number of solutions, improvement of accuracy of the results obtainable from some types of ridges and greater ease in the selection of ridges to invert. The multiscale approach is particularly well suited to deal with non-ideal sources. In these cases, our strategy is to find the optimal combination of upward continuation altitude range and data differentiation order, such that the field could be sensed as approximately homogeneous and then characterized by a structural index close to an integer value. This allows us to estimate depths related to the top or the centre of the structure

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Section: Discussionmentioning

confidence: 97%

Section: O N C L U S I O N Smentioning

confidence: 99%

Multiridge Euler deconvolution

Florio

Fedi

2013

Geophysical Prospecting

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“…Figure 6g shows the structural index depending on the results in Figure 6e computed by equation 3, and the structural indices are from 0.63 to 1.35. Because the shape of the real source is not regular and the anomalies of the sources are overlapped, the structural indices of the sources are fractional, and some authors (Salem and Ravat, 2003;Salem et al, 2008;Fedi et al, 2012) also prove this point.…”

Section: Application To Real Potential Field Datamentioning

confidence: 92%

Combination of horizontal gradient ratio and Euler methods for the interpretation of potential field data

2013

GEOPHYSICS

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The horizontal gradient ratio has been widely used to enhance the linear features of potential field data. I explore a combination of the horizontal gradient ratio and Euler method to interpret gridded potential field data, called HGR-EUL method. A linear equation derived for the Euler equation and expressing the fields as horizontal gradient ratio can be used to estimate the horizontal location and the depth of the source without any priori information about the nature (structural index) of the source. After obtaining the source location parameters, the nature of the source can be determined. The HGR-EUL method is tested on synthetic magnetic anomalies, and the inversion results show that the method can accurately provide the location parameters for noise-free data, and also obtain reasonable results for noise-corrupted data by applying a low pass filter to smooth the data. I also applied the HGR-EUL method to real magnetic data, and the results are compared with results from the standard Euler deconvolution method. The results obtained by the HGR-EUL method show less unjustified variability and are more useful for geologists.

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“…The exponential transform is considered a 'clean' form of filtering since it produces almost no side effects. Upward continuation was used as a form of regional/residual separation in the large scale study of Lyngsie et al (2006) and multi-scale (sequential) upward continuations have been used as a means of depth to source estimation (Fedi et al 2012). Here upward continuation is used only as a means of low-pass filtering.…”

Section: Upward Continuation Filtersmentioning

confidence: 99%

The deep crustal magnetic structure of Britain

Beamish

Kimbell

Pharaoh

2016

Proceedings of the Geologists' Association

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The deep crustal magnetic structure of Britain has not previously been described in a uniform manner. We provide a new assessment of the deep crustal magnetic bodies responsible for the long wavelength magnetic features. The study area contains deep crustal relics of the destruction of early Palaeozoic oceanic lithosphere along the Thor-Tornquist Suture and primarily the Iapetus Suture separating Baltica and Avalonia from the Laurentian terranes. Spectral decomposition is applied to a merged onshore and offshore magnetic anomaly data set. Thirty idealised basement bodies are compared with a representation of the subsurface obtained by a coarse 3D inversion of the data. The central area separating Laurentia and Avalonia, is largely characterised by an absence of high susceptibilities throughout the whole crustal volume. We find that the idealised basement bodies are largely consistent with relatively high susceptibility zones at depths in excess of 10 km. The zones of higher relative susceptibility are referenced to the tectonic-terrane framework of the area and possible geological explanations for the contrasts are reviewed. In the north, the Laurentian terranes are diverse, comprising crust first created in the Archaean (Hebridean Terrane), Palaeoproterozoic (Rhinns Terrane), Mesoproterozoic? (Midland Valley Terrane), Neoproterozoic (sub-Southern Upland rocks) and Ordovician. Magnetic anomalies further record the assembly of the Gondwanan (Eastern Avalonian) part of the country through Neoproterozoic and Ordovician (Tornquist) arc magmatism and accretion. The convergence zones between Laurentia, Avalonia and Baltica have all left a magnetic imprint, as has Variscan convergence to the south.

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Multiscale analysis of potential fields by a ridge consistency criterion: the reconstruction of the Bishop basement

Cited by 37 publications

References 25 publications

Multiridge Euler deconvolution

Multiridge Euler deconvolution

Combination of horizontal gradient ratio and Euler methods for the interpretation of potential field data

The deep crustal magnetic structure of Britain

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