Gradients in the interpretation of satellite-altitude magnetic data: an example from central Africa

Ravat, D.; Wang, B.; Wildermuth, E.; Taylor, Patrick T.

doi:10.1016/s0264-3707(01)00059-x

Cited by 26 publications

(13 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The MF4 SH coefficients, images and animations of the lithospheric field at different altitudes, grids of the vertical component, the total intensity, its spatial derivatives and the analytic signal (Ravat et al 2002a) are available on the MF4 web site at http://www.gfzpotsdam.de/pb2/pb23/SatMag/litmod4.html. Figs 7,8,9,10 and 11 were displayed using GMT (Wessel & Smith 1991).…”

Section: O D E L Ava I L a B I L I T Ymentioning

confidence: 99%

Earth's lithospheric magnetic field determined to spherical harmonic degree 90 from CHAMP satellite measurements

Maus

Rother

Hemant

et al. 2006

Geophysical Journal International

106

107

View full text Add to dashboard Cite

S U M M A R YThe CHAMP magnetic field mission is providing highly reliable measurements from which the global lithospheric magnetic field can be determined in unprecedented resolution and accuracy. Using almost 5 yr of data, we derive our fourth generation lithospheric field model termed MF4, which is expanded to spherical harmonic degree and order 90. After subtracting from the full magnetic field observations predicted fields from an internal field model up to degree 15, an external field model up to degree two, and the predicted magnetic field signatures for the eight dominant ocean tidal constituents, we fit and remove remaining external fields and polar electrojet signatures in a track-by-track scheme. From a subset of least disturbed tracks, we estimate the MF4 model by least squares, damping ill-determined coefficients by regularization. The resulting MF4 model provides a good representation of the lithospheric field down to an altitude of about 50 km at lower latitudes, with reduced accuracy in the polar regions. Crustal features come out significantly sharper than in previous models. In particular, bands of magnetic anomalies along subduction zones become visible by satellite for the first time.

show abstract

Section: O D E L Ava I L a B I L I T Ymentioning

confidence: 99%

Earth's lithospheric magnetic field determined to spherical harmonic degree 90 from CHAMP satellite measurements

Maus

Rother

Hemant

et al. 2006

Geophysical Journal International

106

107

View full text Add to dashboard Cite

show abstract

“…Horizontal derivatives are used for detecting edges of source bodies (Blakely and Simpson 1986; Grauch and Cordell 1987). Both horizontal and vertical derivatives are needed for determining the lateral location and depth of single or multiple simple sources with Euler deconvolution (Thompson 1982; Reid et al 1990; Ravat 1996; Nabighian and Hansen 2001; Hansen and Suciu 2002; Ravat et al 2002; FitzGerald, Reid and McInerney 2004), the 2D analytic signal (Nabighian 1972, 1974) and the 3D total gradient techniques.…”

Section: Introductionmentioning

confidence: 99%

“…Gravity, magnetic field and gradient data are also applied to solid Earth studies, such as crustal structure (Behrendt, Meister and Henderson 1966; Thomas, Grieve and Sharpton 1988; Allen and Hinze 1992; Bosum et al 1997; Cochran et al 1999; Berrino, Corrado and Riccardi 2008), the lithosphere (Martinez, Goodliffe and Taylor 2001; Hebert et al 2001; Jallouli, Mickus and Turki 2002; Abers et al 2002; Fischer 2002), continental rift studies (Martinez et al 2001; Abers et al 2002; Mickus et al 2007), impact structure (Ravat et al 2002), geothermal models (Bektaş et al 2007; Purucker et al 2007), seismicity (Kostoglodov et al 1996), bathymetry (Wang 2000) and volcanic island studies (Carbó et al 2003; Blanco‐Montenegro et al 2005).…”

Section: Introductionmentioning

confidence: 99%

High‐accuracy practical spline‐based 3D and 2D integral transformations in potential‐field geophysics

Wang

Gao

Liu

et al. 2012

Geophysical Prospecting

View full text Add to dashboard Cite

A B S T R A C TPotential, potential field and potential-field gradient data are supplemental to each other for resolving sources of interest in both exploration and solid Earth studies. We propose flexible high-accuracy practical techniques to perform 3D and 2D integral transformations from potential field components to potential and from potential-field gradient components to potential field components in the space domain using cubic B-splines. The spline techniques are applicable to either uniform or non-uniform rectangular grids for the 3D case, and applicable to either regular or irregular grids for the 2D case. The spline-based indefinite integrations can be computed at any point in the computational domain. In our synthetic 3D gravity and magnetic transformation examples, we show that the spline techniques are substantially more accurate than the Fourier transform techniques, and demonstrate that harmonicity is confirmed substantially better for the spline method than the Fourier transform method and that spline-based integration and differentiation are invertible. The cost of the increase in accuracy is an increase in computing time. Our real data examples of 3D transformations show that the spline-based results agree substantially better or better with the observed data than do the Fourier-based results. The spline techniques would therefore be very useful for data quality control through comparisons of the computed and observed components. If certain desired components of the potential field or gradient data are not measured, they can be obtained using the spline-based transformations as alternatives to the Fourier transform techniques.

show abstract

“…The gravity gradient data are widely used in the interpretation of the gravity anomaly, for example, first and second vertical derivatives are commonly computed from gravity data to emphasize short-wavelength anomalies resulting from shallow sources (Gupta and Ramani, 1982;Zeng et al, 1994), horizontal derivatives are now the most common method for detecting target edges (Cordell andGrauch, 1982,1985;Blakely and Simpsom, 1986;Fedi and Florio, 2001;Pearson, 2001;Cooper and Cowan, 2003;Eaton and Vasudevan, 2004). And the gradient data are also necessary to meet the needs of many techniques of data enhancement, direct interpretation, and inversion (Nabighian and Hansen, 2001;Hansen and Suciu, 2002;Ravat et al, 2002;FitzGerald et al, 2004). Traditionally, only the vertical component of the gravity field has been measured because of the ease of obtaining these measurements and interpreting the data.…”

Section: Introductionmentioning

confidence: 99%

Derived the complete gravity gradient tensor from the vertical component of gravity by a cosine transform technique

Jiang

Gao

2010

ASEG Extended Abstracts

View full text Add to dashboard Cite

Gradients in the interpretation of satellite-altitude magnetic data: an example from central Africa

Cited by 26 publications

References 25 publications

Earth's lithospheric magnetic field determined to spherical harmonic degree 90 from CHAMP satellite measurements

Earth's lithospheric magnetic field determined to spherical harmonic degree 90 from CHAMP satellite measurements

High‐accuracy practical spline‐based 3D and 2D integral transformations in potential‐field geophysics

Derived the complete gravity gradient tensor from the vertical component of gravity by a cosine transform technique

Contact Info

Product

Resources

About