Joint inversion of gravity and traveltime data using a level-set based structural approach

Source abstract

We propose a level-set based structural approach for joint inversion of gravity and traveltime data so that density contrast and seismic slowness are simultaneously recovered in the inverse problem. Since density contrast and slowness are different model parameters of the same survey domain, we assume that they are similar in structure in terms of how each property changes and where the interface is located so that we are able to use a level-set function to parameterize the common interface shared by these two model parameters. The level-set parametrization makes it easy to maintain the structural similarity between the two geophysical properties. The inversion of gravity and traveltime data is carried out by minimizing a joint data-fitting function with respect to density contrast, slowness as well as the level-set function. An adjoint state method is used to compute the traveltime gradient efficiently. Numerical examples show that the joint-inversion algorithm effectively improves recovery of subsurface features. The level-set method is a powerful tool to structurally link density contrast and slowness distribution systematically.