Improved imaging of the subsurface using a gravity and magnetotelluric joint inversion

Abstract

We have developed a petrophysical joint inversion between magnetotellurics (MT) and gravity. It utilises Archie?s Law and the porosity-density relationship. Through these equations it can be shown that both conductivity and density are dependant on porosity. Porosity then forms the crucial link between the two techniques used by the joint inversion. The approach was tested using synthetic models. The results demonstrate the joint inversion produces a better representation of the subsurface, as compared to individual MT or gravity inversions. It shows sharper boundaries and more accurate parameter values. Our joint inversion is viable in real Earth applications and this was demonstrated through a case study of the Renmark Trough, South Australia.