HR: 1340h
AN: NG43B-0577    [Abstracts]
TI: Inversion of 3D potiential field data by using simulated annealing
AU: * Ortiz-Aleman, C
EM: jcortiz@imp.mx
AF: Instituto Mexicano del Petroleo, Eje central Lazaro Cardenas 152, Mexico City, Mex 07730 Mexico
AU: Mu¤oz-Gonzalez, S
EM: smunoz@imp.mx
AF: Instituto Mexicano del Petroleo, Eje central Lazaro Cardenas 152, Mexico City, Mex 07730 Mexico
AU: Alejandro, C
EM: aceron@imp.mx
AF: Instituto Mexicano del Petroleo, Eje central Lazaro Cardenas 152, Mexico City, Mex 07730 Mexico
AB: We introduce a numerically improved inversion approach for 3D potential field modeling based on simulated annealing. In this simulated annealing inversion method, a large linear system of algebraic equations is solved by minimizing iteratively an energy function. The vector of unknown densities is repeatedly updated, in a semi-random process that mimics the thermodynamic phenomenon of crystallization in a liquid that is being cooled. In this work, the energy function is calculated by using a numerically optimized matrix by vector multiplication approach that avoids redundant computations. The unknowns are refined as they go through the processes of cooling and random perturbation until their calculated data match the right-hand-side data vector in a least squares sense. The matrix by vector multiplication involved in the computation of the energy function can be significantly accelerated as each new vector of unknowns is roughly the same as the previous one, except for one perturbed term. We found this technique to be faster and more accurate than traditional linear solvers. This approach can be applied to the inversion of linear models in general, as it works well with no need of any regularization or preconditioning and its speed of computation is comparable to other commonly used linear approaches as the conjugate gradient method. We show some applications of this method to synthetic and real potential field data.
DE: 3225 Numerical approximations and analysis (4260)
DE: 3252 Spatial analysis (0500)
DE: 3260 Inverse theory
DE: 3294 Instruments and techniques
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005