  We implement the 3D Marchenko equations to retrieve responses to virtual
sources inside the subsurface. For this, we require reflection data at the
surface of the Earth that contain no free-surface multiples and are densely
sampled in space. The required 3D reflection data volume is very large and
solving the Marchenko equations requires a significant amount of computational
cost. To limit the cost, we apply floating point compression to the reflection
data to reduce their volume and the loading time from disk. We apply the
Marchenko implementation to numerical reflection data to retrieve accurate
Green's functions inside the medium and use these reflection data to apply
imaging. This requires the simulation of many virtual source points, which we
circumvent by using virtual plane-wave sources instead of virtual point
sources. Through this method, we retrieve the angle-dependent response of a
source from a depth level rather than of a point. We use these responses to
obtain angle-dependent structural images of the subsurface, free of
contamination from wrongly imaged internal multiples. These images have less
lateral resolution than those obtained using virtual point sources, but are
more efficiently retrieved.
