Regularization and inversion of 2‐D gravity data

1993 ◽  
Author(s):  
A. Bassrei
Keyword(s):  
Gravity Data ◽  
And Inversion

2D modeling and inversion of gravity data using density contrast varying with depth and source–basement geometry described by the Fourier series

Geophysics ◽  
2003 ◽  
Vol 68 (6) ◽  
pp. 1909-1916 ◽  
Author(s):  
Juan García‐Abdeslem
Keyword(s):  
Fourier Series ◽  
Gravity Data ◽  
Forward Modeling ◽  
Density Contrast ◽  
Nonlinear Inversion ◽  
Bouguer Gravity ◽  
Data Set ◽  
Cubic Polynomial ◽  
Broad Variety ◽  
And Inversion

A method is developed for 2D forward modeling and nonlinear inversion of gravity data. The forward modeling calculates the gravity anomaly caused by a 2D source body with an assumed depth‐dependent density contrast given by a cubic polynomial. The source body is bounded at depth by a smooth, curvilinear surface given by the Fourier series, which represents the basement. The weighted and damped discrete nonlinear inverse method presented here can invert gravity data to infer the geometry of the source body. The use of the Fourier series to define the basement geometry allows the interpreter to reconstruct a broad variety of geometries for the geologic structures using a small number of free parameters. Both modeling and inversion methods are illustrated with examples using field gravity data across the San Jacinto graben in southern California and across the Sayula basin in Jalisco, Mexico. The inversion of the San Jacinto graben residual Bouguer gravity data yields results compatible with those from previous interpretations of the same data set, suggesting that this geologic structure accommodates about 2.5 km of sediments. The inversion of the residual Bouguer gravity data across the Sayula basin suggests a maximum of 1‐km‐thick sedimentary infill.

scholarly journals A Methodology for Filtering and Inversion of Gravity Data: An Example of Application to the Determination of the Moho Undulation in Morocco

Engineering ◽  
2010 ◽  
Vol 02 (03) ◽  
pp. 149-159 ◽  
Author(s):  
Victor Corchete ◽  
Mimoun Chourak ◽  
Driss Khattach
Keyword(s):  
Gravity Data ◽  
And Inversion

Extrapolated Tikhonov method and inversion of 3D density images of gravity data

2014 ◽  
Vol 11 (2) ◽  
pp. 139-148 ◽  
Author(s):  
Zhu-Wen Wang ◽  
Shi Xu ◽  
Yin-Ping Liu ◽  
Jing-Hua Liu
Keyword(s):  
Gravity Data ◽  
Tikhonov Method ◽  
And Inversion

scholarly journals Interpretação gravimétrica na Borda Norte do Cráton do Congo, Sul de Camarões

2010 ◽  
Vol 33 (1) ◽  
pp. 73-82
Author(s):  
Yves N Shandini ◽  
Jean Marie Tadjou ◽  
Charles T Tabod ◽  
James Derek Fairhead
Keyword(s):  
Gravity Data ◽  
Bouguer Anomaly ◽  
Gravity Anomalies ◽  
Continental Collision ◽  
Tectonic Structures ◽  
Collision Zone ◽  
Granitic Intrusion ◽  
Southern Cameroon ◽  
Northern Edge ◽  
And Inversion

Gravity data in the southern Cameroon are interpreted to better understand the organization of underlying structures throughout the northern edge of the Congo craton. The Bouguer anomaly maps of the region are characterized by an elongated SW-NE trending negative gravity anomaly which correspond to a collapsed structure associated with a granitic intrusion beneath the center of the region and limited by fault systems. We applied 3-D gravity modelling and inversion in order to obtain the 3-D density structure of the area. Our result demonstrated that observed gravity anomalies in the region are associated to tectonic structures in the subsurface. The resulting model agrees with the hypothesis of the existence of a major continental collision zone between the Congo Craton and the Pan-African belt. The presence of deep granulites structures in the northern part of the region expresses a continental collision.

Inversion of the power spectrum from gravity anomalies of prismatic bodies

Geophysics ◽  
1995 ◽  
Vol 60 (6) ◽  
pp. 1698-1703 ◽  
Author(s):  
Juan García‐Abdeslem
Keyword(s):  
Inverse Problem ◽  
Power Spectrum ◽  
Ridge Regression ◽  
Field Data ◽  
Gravity Data ◽  
Source Parameters ◽  
Gravity Anomalies ◽  
Independent Functions ◽  
Prismatic Bodies ◽  
And Inversion

I develop methods for modeling and inversion of gravity anomalies produced by prismatic bodies. The forward problem is solved in the wavenumber domain, where the power spectrum of the gravity anomaly is given by the product of independent functions that describe depth, thickness, horizontal dimensions, and density of the source body. The solution of the inverse problem is based on an iterative ridge‐regression algorithm, starting from an initial trial of the geometry and density of the source body. This procedure is assessed in a number of examples with both numeric and field data spectra. The method is first tested on the spectrum obtained from simple gravity anomalies and is found to be capable of recovering the source parameters. Next the method is applied to gravity data from a survey made near Noranda, Quebec, Canada. This interpretation compares favorably with drillhole data and provides an estimation of the mass of the source body which is similar to previous estimates.

Three‐dimensional regularized focusing inversion of gravity gradient tensor component data

Geophysics ◽  
2004 ◽  
Vol 69 (4) ◽  
pp. 925-937 ◽  
Author(s):  
Michael S. Zhdanov ◽  
Robert Ellis ◽  
Souvik Mukherjee
Keyword(s):  
Local Density ◽  
Mineral Exploration ◽  
Gravity Data ◽  
Three Dimensional ◽  
Tensor Component ◽  
Airborne Gravity ◽  
Gravity Gradient ◽  
Gravity Method ◽  
Density Anomaly ◽  
And Inversion

We develop a new method for interpretation of tensor gravity field component data, based on regularized focusing inversion. The focusing inversion makes its possible to reconstruct a sharper image of the geological target than conventional maximum smoothness inversion. This new technique can be efficiently applied for the interpretation of gravity gradiometer data, which are sensitive to local density anomalies. The numerical modeling and inversion results show that the resolution of the gravity method can be improved significantly if we use tensor gravity data for interpretation. We also apply our method for inversion of the gradient gravity data collected by BHP Billiton over the Cannington Ag‐Pb‐Zn orebody in Queensland, Australia. The comparison with the drilling results demonstrates a remarkable correlation between the density anomaly reconstructed by the gravity gradient data and the true structure of the orebody. This result indicates that the emerging new geophysical technology of the airborne gravity gradient observations can improve significantly the practical effectiveness of the gravity method in mineral exploration.

Reformulation of Parker–Oldenburg's method for Earth's spherical approximation

2020 ◽  
Vol 222 (2) ◽  
pp. 1046-1073
Author(s):  
Wenjin Chen ◽  
Robert Tenzer
Keyword(s):  
Gravity Field ◽  
Large Scale ◽  
Gravity Data ◽  
Spherical Approximation ◽  
Gravity Gradient ◽  
Global Studies ◽  
Forward Modelling ◽  
Density Interface ◽  
And Inversion ◽  
Interface Geometry

SUMMARY Parker–Oldenburg's method is perhaps the most commonly used technique to estimate the depth of density interface from gravity data. To account for large density variations reported, for instance, at the Moho interface, between the ocean seawater density and marine sediments, or between sediments and the underlying bedrock, some authors extended this method for variable density models. Parker–Oldenburg's method is suitable for local studies, given that a functional relationship between gravity data and interface geometry is derived for Earth's planar approximation. The application of this method in (large-scale) regional, continental or global studies is, however, practically restricted by errors due to disregarding Earth's sphericity. Parker–Oldenburg's method was, therefore, reformulated also for Earth's spherical approximation, but assuming only a uniform density. The importance of taking into consideration density heterogeneities at the interface becomes even more relevant in the context of (large-scale) regional or global studies. To address this issue, we generalize Parker–Oldenburg's method (defined for a spherical coordinate system) for the depth of heterogeneous density interface. Furthermore, we extend our definitions for gravity gradient data of which use in geoscience applications increased considerably, especially after launching the Gravity field and steady-state Ocean Circulation Explorer (GOCE) gravity-gradiometry satellite mission. For completeness, we also provide expressions for potential. The study provides the most complete review of Parker–Oldenburg's method in planar and spherical cases defined for potential, gravity and gravity gradient, while incorporating either uniform or heterogeneous density model at the interface. To improve a numerical efficiency of gravimetric forward modelling and inversion, described in terms of spherical harmonics of Earth's gravity field and interface geometry, we use the fast Fourier transform technique for spherical harmonic analysis and synthesis. The (newly derived) functional models are tested numerically. Our results over a (large-scale) regional study area confirm that the consideration of a global integration and Earth's sphericty improves results of a gravimetric forward modelling and inversion.

Layer Constrained Composite Modelling and Inversion of Gravity Data

2016 ◽  
Author(s):  
V. Vandone ◽  
F. Chiappa ◽  
P. Marchetti ◽  
G. Bernasconi ◽  
P. Dell'Aversana
Keyword(s):  
Gravity Data ◽  
And Inversion
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