GNGTS 2016 - Atti del 35° Convegno Nazionale

592 GNGTS 2016 S essione 3.3 unit density and plotted with observed gravity anomaly (Fig. 3d) in order to calculate slop of the fitted line that is actually density contrast. The estimated density is -0.43 g/cm2, which is slightly higher than Rao (1990) calculated. The resulting model by the current method is plotted with that of Rao (1990) that shows a good agreement (Fig. 3e). Conclusions. We have developed an automatic multi-scale inversion method using MHODE. It allows the calculation of the entire geometry of a causative body and its depth. The method yielded complete information of the unknown source parameters and density. The main advantage of MHODE is its independence on a priori information on density, unlike standard inversion methods. This reduces the ambiguity of the problem. The method is also stable in presence of noise, since it is based on inversion of multi-scale dataset. References Bhaskara Rao, V., and Venkateswarulu, P. D., 1974, A simple method of interpreting gravity anomalies over sedimentary basins: Geophys. Res. Bull., 12, 177-182. Blakely, R. J., 1996, Potential Theory in gravity and magnetic applications; Cambridge University Press. Coleman, T. F., and Y. Li, 1996, An interior trust region approach for nonlinear minimization subject to bounds; SIAM Journal on Optimization, 6, no. 2, 418–445. Fedi, M., 2007, DEXP: A fast method to determine the depth and the structural index of potential fields sources; Geophysics, 72, no. 1, I1–I11. Fedi, M., F. Cella, T. Quarta, and A. Villani, 2010, 2D continuous wavelet transform of potential fields due to extended source distributions; Applied and Computational Harmonic Analysis, 28, no. 3, 320–337. Fedi, M., G. Florio, and V. Paoletti, 2015, MHODE: a local-homogeneity theory for improved source-parameter estimation of potential fields; Geophysical Journal International, 202 (2): 887-900. Fedi, M., G. Florio, and T. Quarta, 2009, Multiridge analysis of potential fields: Geometric method and reduced Euler deconvolution; Geophysics, 74, no. 4, L53–L65. Florio, G., and M. Fedi, 2014, Multiridge Euler deconvolution; Geophysical Prospecting, 62, no. 2, 333– 351. Hansen, R. O., and L. Suciu, 2002, Multiple-source Euler deconvolution; Geophysics, 67, 525– 535. Ingber, L., 1989, Very fast simulated reannealing, Mathl. Comput. Modeling, 12(8).967–993. Ingber, L., 1993, Simulated annealing: Practice versus theory, Mathl. Comput. Modeling,18(11), 29–57. Moreau, F., D. Gibert, M. Holschneider, and G. Saracco, 1997, Wavelet analysis of potential fields; Inverse Problems, 13, no. 1, 165–178. Nabighian, M. N., 1972, The analytic signal of two-dimensional magnetic bodies with polygonal cross- section: Its properties and use for automated anomaly interpretation; Geophysics, 37, 507– 517. Rao, D. B., 1990, Analysis of gravity anomalies of sedimentary basins by an asymmetrical trapezoidal model with quadratic density function; Geophysics, 55, 226-31. Reid, A. B., J. M. Allsop, H. Granser, A. J. Millett, and I. W. Somerton, 1990, Magnetic interpretation in three dimensions using Euler deconvolution; Geophysics, 55, 80–91. Sen, M. K., Stoffa, P. L., 1995, Global optimization method in geophysical inversion, Elsevier. Steenland, N. C., 1968, The geomagnetic gradiometer by H. A. Slack, V. M. Lynch, and L. Langan (Geophysics, October 1967, 877–892); Geophysics, 33, 680–686. Talwani, M., J. L. Worzel, and M. Landisman, 1959, Rapid gravity computations for two-dimensional bodies with application to the Mendocino submarine fracture zone; Journal of Geophysical Research, 64, no. 1, 49–59. Thompson, D. T., 1982, EULDPH: a new technique for making computer-assisted depth estimates from magnetic data; Geophysics, 47, 31–37. Thurston, J. B., and R. S. Smith, 1997, Automatic conversion of magnetic data to depth, dip, and susceptibility contrast using the SPI method: Geophysics, 62, 807–813.