Presenting a Free, Highly Flexible Inversion Code

Electrical and electromagnetic methods are used widely in the geophysical community. We present the, for the scientific community free, inversion code em1dinv that handles numerous data types as well as constraints in the model space. The em1dinv code developed at the University of Aarhus, does 1D inversions on many different data types: surface DC, borehole DC, borehole DC in cylinder symmetric coordinates, time domain (TEM), frequency domain (FEM), magneto telluric (MT), airborne time domain, airborne frequency domain and surface wave dispersion curves (SWD). In addition it will also do 2D inversion of DC data. Individual inversions of these data types are not unique, but the em1dinv code allows for any combination of the data types as either joint inversions or combined inversions. Also the code uses laterally constrained inversion (LCI) to mimic sedimentary and other quasi-layered environments. Finally, a full model parameter sensitivity analysis is calculated for the inversion result regardless of the data type. Thus, using the full flexibility of the code in many cases allows for a detailed description of the subsurface with less uncertainty on the estimated parameters. This paper presents a number of the different uses of the code.