A Fortran 77 computer code for damped least-squares inversion of Slingram electromagnetic anomalies over thin tabular conductors


COMPUTERS & GEOSCIENCES, vol.30, no.6, pp.591-599, 2004 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 30 Issue: 6
  • Publication Date: 2004
  • Doi Number: 10.1016/j.cageo.2004.02.003
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.591-599
  • Keywords: Slingram anomaly, perfect tabular conductors, least-squares inversion, numerical differentiation, FORTRAN 77, PROSPECTING SYSTEM, MAGNETIC-ANOMALIES, PROGRAM
  • Dokuz Eylül University Affiliated: Yes


A FORTRAN 77 computer code is presented that permits the inversion of Slingram electromagnetic anomalies to an optimal conductor model. Damped least-squares inversion algorithm is used to estimate the anomalous body parameters, e.g. depth, dip and surface projection point of the target. Iteration progress is controlled by maximum relative error value and iteration continued until a tolerance value was satisfied, while the modification of Marquardt's parameter is controlled by sum of the squared errors value. In order to form the Jacobian matrix, the partial derivatives of theoretical anomaly expression with respect to the parameters being optimised are calculated by numerical differentiation by using first-order forward finite differences.