Refinement of three-dimensional multilayer models of basins and crustal environments by inversion of gravity and magnetic data

2005 ◽  
Vol 397 (1-2) ◽  
pp. 37-54 ◽  
Author(s):  
Luis A. Gallardo ◽  
M.A. Pérez-Flores ◽  
E. Gómez-Treviño
Keyword(s):  
Three Dimensional ◽  
Magnetic Data ◽  
Gravity And Magnetic ◽  
Gravity And Magnetic Data

Cross-gradients joint 3D inversion with applications to gravity and magnetic data

Geophysics ◽  
2009 ◽  
Vol 74 (4) ◽  
pp. L31-L42 ◽  
Author(s):  
Emilia Fregoso ◽  
Luis A. Gallardo
Keyword(s):  
Joint Inversion ◽  
Three Dimensional ◽  
Structural Similarity ◽  
Solution Procedure ◽  
Magnetic Data ◽  
3D Inversion ◽  
Gravity And Magnetic ◽  
New Formulation ◽  
Value Decomposition ◽  
Gravity And Magnetic Data

We extend the cross-gradient methodology for joint inversion to three-dimensional environments and introduce a solution procedure based on a statistical formulation and equality constraints for structural similarity resemblance. We apply the proposed solution to the joint 3D inversion of gravity and magnetic data and gauge the advantages of this new formulation on test and field-data experiments. Combining singular-value decomposition (SVD) and other conventional regularizing constraints, we determine 3D distributions of the density and magnetization with enhanced structural similarity. The algorithm reduces some misleading features of the models, which are introduced commonly by conventional separate inversions of gravity and magnetic data, and facilitates an integrated interpretation of the models.

Automatic 3-D interpretation of potential field data using analytic signal derivatives

Geophysics ◽  
1997 ◽  
Vol 62 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Nicole Debeglia ◽  
Jacques Corpel
Keyword(s):  
Signal Amplitude ◽  
Vertical Gradient ◽  
Analytic Signal ◽  
Magnetic Data ◽  
Practical Implementation ◽  
Potential Field Data ◽  
Gravity And Magnetic ◽  
Second Derivatives ◽  
Gravity And Magnetic Data ◽  
Derivatives Of

A new method has been developed for the automatic and general interpretation of gravity and magnetic data. This technique, based on the analysis of 3-D analytic signal derivatives, involves as few assumptions as possible on the magnetization or density properties and on the geometry of the structures. It is therefore particularly well suited to preliminary interpretation and model initialization. Processing the derivatives of the analytic signal amplitude, instead of the original analytic signal amplitude, gives a more efficient separation of anomalies caused by close structures. Moreover, gravity and magnetic data can be taken into account by the same procedure merely through using the gravity vertical gradient. The main advantage of derivatives, however, is that any source geometry can be considered as the sum of only two types of model: contact and thin‐dike models. In a first step, depths are estimated using a double interpretation of the analytic signal amplitude function for these two basic models. Second, the most suitable solution is defined at each estimation location through analysis of the vertical and horizontal gradients. Practical implementation of the method involves accurate frequency‐domain algorithms for computing derivatives with an automatic control of noise effects by appropriate filtering and upward continuation operations. Tests on theoretical magnetic fields give good depth evaluations for derivative orders ranging from 0 to 3. For actual magnetic data with borehole controls, the first and second derivatives seem to provide the most satisfactory depth estimations.

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