IUGG 2023: Is forward modeling still up to date?

Abstract

Forward modeling in potential field data interpretation is a valuable tool for improving the significance of geophysical interpretations since decades. It allows for model validation and discrimination, parameter and depth estimations, and accommodation of complex subsurface structures, as well as topographic corrections in both Geophysics and Geodesy. Three tasks relevant to forward modelling are in our focus: “model validation” – testing accuracy and reliability of a geological model by comparing predicted/modelled data with field observations, “inversion optimization” – improvement of the accuracy of inversion results by incorporating constraints from forward modeling, and “sensitivity analysis” – evaluation of the sensitivity of the modeled data to changes in the model parameters, which can be used to make a more informed decision on the most likely underground model. While in the early days forward modeling was characterized using simple solids, such as spheres or rectangular prisms, to represent the subsurface structure, nowadays flexible polyhedra are available to deal with complicated subsurface structures for plane and spherical model calculations. Combined with modern computer graphics, interactive forward processing is possible “on the fly” and accompanied by the visualization of the broad spectrum of diverse model constraints. This enables an interdisciplinary “model discrimination” which assists in differentiating between multiple possible forward models by comparing the predicted data from each model with the observed data. Modeling case studies on small and large (global) scales will demonstrate these workflows by the aid of a software the team developed over the last decade.