A sparse spectrum technique for gridding and separating potential field anomalies

Guspi, Fenando; Introcaso, Beatriz

doi:10.1190/1.1885937

Cited by 6 publications

(5 citation statements)

References 6 publications

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“…The depth to the source bodies is related to the slope of the logarithm of the power spectrum as a function of the logarithm of the wave number. These depths represent statistical estimates of the interfaces, which allow for an evaluation of an average structural model (Lim & Malik, 1981;Guspí & Introcaso, 2000).…”

Section: Spectral Analysismentioning

confidence: 99%

The evolution of the high‐elevated depocenters of the northern Sierras Pampeanas (ca. 28˚ SL), Argentine broken foreland, South‐Central Andes: the Pipanaco Basin

Dávila

Giménez²,

Nóbile

et al. 2012

Basin Research

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The Pipanaco Basin, in the southern margin of the Andean Puna plateau at ca. 28°SL, is one of the largest and highest intermontane basins within the northernmost Argentine broken foreland. With a surface elevation >1000 m above sea level, this basin represents a strategic location to understand the subsidence and subsequent uplift history of high‐elevation depositional surfaces within the distal Andean foreland. However, the stratigraphic record of the Pipanaco Basin is almost entirely within the subsurface, and no geophysical surveys have been conducted in the region. A high‐resolution gravity study has been designed to understand the subsurface basin geometry. This study, together with stratigraphic correlations and flexural and backstripping analysis, suggests that the region was dominated by a regional subsidence episode of ca. 2 km during the Miocene‐Pliocene, followed by basement thrusting and ca. 1–1.5 km of sediment filling within restricted intermontane basin between the Pliocene‐Pleistocene. Based on the present‐day position of the basement top as well as the Neogene‐Present sediment thicknesses across the Sierras Pampeanas, which show slight variations along strike, sediment aggradation is not the most suitable process to account for the increase in the topographic level of the high‐elevation, close‐drainage basins of Argentina. The close correlation between the depth to basement and the mean surface elevations recorded in different swaths indicates that deep‐seated geodynamic process affected the northern Sierras Pampeanas. Seismic tomography, as well as a preliminary comparison between the isostatic and seismic Moho, suggests a buoyant lithosphere beneath the northern Sierras Pampeanas, which might have driven the long‐wavelength rise of this part of the broken foreland after the major phase of deposition in these Andean basins.

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Section: Spectral Analysismentioning

confidence: 99%

The evolution of the high‐elevated depocenters of the northern Sierras Pampeanas (ca. 28˚ SL), Argentine broken foreland, South‐Central Andes: the Pipanaco Basin

Dávila

Giménez²,

Nóbile

et al. 2012

Basin Research

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“…Estimation of the optimum value of α is an important task and there exists a large group of different approaches (e.g., Hansen 1998; Zhdanov 2002; Berdichevski and Dmitriev 2002). The widely used concepts (known to the authors) are methods based on the estimation of the error distribution in the input data (e.g., Sacchi and Ulrych 1996; Guspí and Introcaso 2000) and finding the optimum value in an iterative process (e.g., Portniaguine and Zhdanov 1999, 2002). Here, we use the C‐norm approach of Tikhonov et al (1968), where we construct a C‐norm of the difference between two adjacent solutions (obtained for different values of α), plotted against α (see Fig.…”

Section: Methodology Of the Regularized Derivative Evaluationmentioning

confidence: 99%

Regularized derivatives of potential fields and their role in semi‐automated interpretation methods

Pašteka

Richter

Karcol

et al. 2009

Geophysical Prospecting

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A B S T R A C TEvaluation of higher derivatives (gradients) of potential fields plays an important role in geophysical interpretation (qualitative and/or quantitative), as has been demonstrated in many approaches and methods. On the other hand, numerical evaluation of higher derivatives is an unstable process -it has the tendency to enlarge the noise content in the original data (to degrade the signal-to-noise ratio). One way to stabilize higher derivative evaluation is the utilization of the Tikhonov regularization.In the submitted contribution we present the derivation of the regularized derivative filter in the Fourier domain as a minimization task by means of using the classical calculus of variations. A very important part of the presented approach is the selection of the optimum regularization parameter -we are using the analysis of the C-norm function (constructed from the difference between two adjacent solutions, obtained for different values of regularization parameter). We show the influence of regularized derivatives on the properties of the classical 3D Euler deconvolution algorithm and apply it to high-sensitivity magnetometry data obtained from an unexploded ordnance detection survey. The solution obtained with regularized derivatives gives better focused depth-estimates, which are closer to the real position of sources (verified by excavation of unexploded projectiles). I N T R O D U C T I O NSemi-automated interpretation methods in applied gravimetry and magnetometry are based on estimation of source parameters directly from the measured (processed) and/or transformed potential fields. These methods are built on introduction of a priori information on the properties of the desired solution, mainly at the mathematical level. In the majority of cases, the a priori information is based on the recognition of a predefined source type response in the interpreted data. This approach does not fully solve the ambiguity of the inverse problem in potential field's interpretation. By means of this approach, we introduce into the solutions the so-called model error (Dmitriev et al. 1990) -this is connected with the problem of description of the complex real situations by sim- * E-mail: pasteka@fns.uniba.sk ple models. The problem of the instability of inverse problem solutions is manifested in these kinds of methods by a great sensitivity to the noise and errors in the interpreted fields.A large group of these interpretation methods use higher gradients of the interpreted field (e.g., Werner and Euler deconvolution, methods based on analytical signal evaluation, normalized derivative methods and many other approaches, e.g.

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“…Clear breaks between lowand high-frequency components of the spectrum were used to design either band-pass or matched filters. Guspi and Introcaso (2000) used the spectrum of observed data and looked for clear breaks between the low-and high-frequency components of the spectrum to separate the regional and residual fields.…”

Section: Regional-residual Separationmentioning

confidence: 99%

Historical development of the gravity method in exploration

et al. 2005

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The gravity method was the first geophysical technique to be used in oil and gas exploration. Despite being eclipsed by seismology, it has continued to be an important and sometimes crucial constraint in a number of exploration areas. In oil exploration the gravity method is particularly applicable in salt provinces, overthrust and foothills belts, underexplored basins, and targets of interest that underlie high-velocity zones. The gravity method is used frequently in mining applications to map subsurface geology and to directly calculate ore reserves for some massive sulfide orebodies. There is also a modest increase in the use of gravity techniques in specialized investigations for shallow targets. Gravimeters have undergone continuous improvement during the past 25 years, particularly in their ability to function in a dynamic environment. This and the advent of global positioning systems (GPS) have led to a marked improvement in the quality of marine gravity and have transformed airborne gravity from a regional technique to a prospect-level exploration tool that is particularly applicable in remote areas or transition zones that are otherwise inaccessible. Recently, moving-platform gravity gradiometers have become available and promise to play an important role in future exploration. Data reduction, filtering, and visualization, together with low-cost, powerful personal computers and color graphics, have transformed the interpretation of gravity data. The state of the art is illustrated with three case histories: 3D modeling of gravity data to map aquifers in the Albuquerque Basin, the use of marine gravity gradiometry combined with 3D seismic data to map salt keels in the Gulf of Mexico, and the use of airborne gravity gradiometry in exploration for kimberlites in Canada.

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A sparse spectrum technique for gridding and separating potential field anomalies

Cited by 6 publications

References 6 publications

The evolution of the high‐elevated depocenters of the northern Sierras Pampeanas (ca. 28˚ SL), Argentine broken foreland, South‐Central Andes: the Pipanaco Basin

The evolution of the high‐elevated depocenters of the northern Sierras Pampeanas (ca. 28˚ SL), Argentine broken foreland, South‐Central Andes: the Pipanaco Basin

Regularized derivatives of potential fields and their role in semi‐automated interpretation methods

Historical development of the gravity method in exploration

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