Geometric shapes derived from airborne gravity gradiometry data: New tools for the explorationist

Chowdhury, Priyanka; Cevallos, Carlos

doi:10.1190/tle32121468.1

Cited by 8 publications

(4 citation statements)

References 15 publications

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“…In recent years, gravity gradiometry surveys have been widely conducted to obtain detailed subsurface structure data (e.g., Jekeli 1988;Dransfield 2010;Chowdhury and Cevallos 2013;Braga et al 2014). Data collected by these surveys is the gravity gradient tensor defined by second derivatives of the gravity potential, and its response to subsurface structures is more sensitive than the gravity anomaly.…”

Section: Introductionmentioning

confidence: 99%

Eigenvector of gravity gradient tensor for estimating fault dips considering fault type

Kusumoto

2017

Prog. in Earth and Planet. Sci.

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The dips of boundaries in faults and caldera walls play an important role in understanding their formation mechanisms. The fault dip is a particularly important parameter in numerical simulations for hazard map creation as the fault dip affects estimations of the area of disaster occurrence. In this study, I introduce a technique for estimating the fault dip using the eigenvector of the observed or calculated gravity gradient tensor on a profile and investigating its properties through numerical simulations. From numerical simulations, it was found that the maximum eigenvector of the tensor points to the high-density causative body, and the dip of the maximum eigenvector closely follows the dip of the normal fault. It was also found that the minimum eigenvector of the tensor points to the low-density causative body and that the dip of the minimum eigenvector closely follows the dip of the reverse fault. It was shown that the eigenvector of the gravity gradient tensor for estimating fault dips is determined by fault type. As an application of this technique, I estimated the dip of the Kurehayama Fault located in Toyama, Japan, and obtained a result that corresponded to conventional fault dip estimations by geology and geomorphology. Because the gravity gradient tensor is required for this analysis, I present a technique that estimates the gravity gradient tensor from the gravity anomaly on a profile.

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Section: Introductionmentioning

confidence: 99%

Eigenvector of gravity gradient tensor for estimating fault dips considering fault type

Kusumoto

2017

Prog. in Earth and Planet. Sci.

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“…Curvatures of equipotential surfaces and their application to gravity gradiometry are well known; they are a function of the gravity and the gravity gradients and can be applied to interpret gravity gradients in geophysical applications (Cevallos et al, 2013;Chowdhury and Cevallos, 2013;Li and Cevallos, 2013;Cevallos, 2014;Li, 2015).…”

Section: Introductionmentioning

confidence: 99%

Interpreting the direction of the gravity gradient tensor eigenvectors: The main tidal force and its relation to the curvature parameters of the equipotential surface

Cevallos¹

2016

ASEG Extended Abstracts

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Rotating the gravity gradient tensor about a vertical axis by an appropriate angle allows one to express its components as functions of the curvatures of the equipotential surface. The description permits the identification of the gravity gradient tensor as the Newtonian tidal tensor and part of the tidal potential. The identification improves the understanding and interpretation of gravity gradient data. With the use of the plunge of the eigenvector associated with the largest eigenvalue or plunge of the main tidal force, it is possible to estimate the location and depth of buried gravity sources; this is illustrated in model data and applied to FALCON airborne gravity gradiometer data from the Canning Basin, Australia.

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“…The equipotential surface is a gravity quantity and is closely linked to a particular geometric surface of the earth. Curvature of the equipotential surface is a function of the gravity and the gravity gradients and may thus be used to interpret gravity gradients measured by modern gravity gradiometry technologies (Cevallos et al, 2013;Chowdhury and Cevallos, 2013;Li and Cevallos, 2013). However, approximations have to be made when curvature of the equipotential surface is applied to field data.…”

Section: Introductionmentioning

confidence: 99%

Curvature of a geometric surface and curvature of gravity and magnetic anomalies

Li¹

2015

GEOPHYSICS

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Curvature describes how much a line deviates from being straight or a surface from being flat. When curvature is used to interpret gravity and magnetic anomalies, we try to delineate geometric information of subsurface structures from an observed nongeometric quantity. In this work, I evaluated curvature attributes of the equipotential surface as functions of gravity gradients and analyzed the differences between the theoretical derivation and a practical application. I computed curvature of a synthetic model that consisted of representative structures (ridge, valley, basin, dome, and vertical cylinder) and curvature of the equipotential surface, gravity, and vertical gravity gradient (which is equivalent to the magnetic reduction-to-the-pole result) due to the same model. A comparison of curvature of such a geometric surface and curvature of different gravity quantities was then made to help understand these curvature differences and an indirect link between curvature of gravity data and actual structures. Finally, I applied curvature analysis to a magnetic anomaly grid in the Gaspé belt of Quebec, Canada, to illustrate its useful property of enhancing subtle features.

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Geometric shapes derived from airborne gravity gradiometry data: New tools for the explorationist

Cited by 8 publications

References 15 publications

Eigenvector of gravity gradient tensor for estimating fault dips considering fault type

Eigenvector of gravity gradient tensor for estimating fault dips considering fault type

Interpreting the direction of the gravity gradient tensor eigenvectors: The main tidal force and its relation to the curvature parameters of the equipotential surface

Curvature of a geometric surface and curvature of gravity and magnetic anomalies

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