Focusing conditions: a comparison between different Marchenko imaging strategies

Marchenko imaging allows retrieving images from single-sided reflection measurements without artefacts due to internal multiples. A key step in Marchenko imaging is the retrieval of the so-called focusing function from the reflection measurements and a background model. The conventional focusing function obeys a point focusing condition, i.e. it focuses inside the medium of interest both in space and in time. Based on this focusing property one can retrieve up- and downgoing Green’s functions that are associated with a virtual point source or receiver inside the medium, which can be used for imaging. Recently, a new focusing function has been introduced that creates a plane wave instead of a point focus. Using the new focusing function one can retrieve medium responses associated to an up- and downgoing plane wave source or receiver inside the medium, enabling imaging based on plane wave sources. We compare Marchenko imaging using the conventional and the new focusing condition.