f The use of structurally coupled cooperative inversion in conjunction with cluster analysis towards a comprehensive subsurface characterization

The use of multiple physical principles and data is a common rule in geophysics in order to narrow the variety of possible interpretations. However, in most cases this is done on the interpretation level. A more rigorous reduction of ambiguity can be achieved by coupling within the inversion level. In order to combine data that are not directly related to each other, two main ways exist: • use of petrophysical relations to redirect the output parameters to a common parameter set • structural coupling of otherwise independent inversions based on the model characteristics We use the latter way, for which various approaches have been presented. Günther & Rücker (2006) used a generalized smoothness-constrained inversion scheme and on this basis Günther & Bentley (2006) presented a structural coupling between resistivity and velocity using the gradients of the individual models. An IRLS function is used to predict weights for the model boundary based on co-located model gradients of the other method. As a result, we obtain two physical properties on the same discretisation. Further methods such as cluster analysis can be used to produce a comprehensive subsurface model. Fuzzy c-means clustering yields not only the cluster membership for each model cell, but also a matching function can be derived that is of valuable help in the interpretation.<br>