Green's function representations for Marchenko imaging without up/down decomposition

TL;DR

This paper introduces new Green's function representations for Marchenko imaging that do not rely on the traditional up/down wave decomposition, enabling improved imaging of complex subsurface features.

Contribution

A novel derivation of Green's function representations that removes the need for wave decomposition assumptions in Marchenko methods for acoustic and elastodynamic cases.

Findings

Potential to handle refracted and evanescent waves

More accurate imaging of steeply dipping reflectors

Foundation for advanced Marchenko techniques

Abstract

Marchenko methods are based on integral representations which express Green's functions for virtual sources and/or receivers in the subsurface in terms of the reflection response at the surface. An underlying assumption is that inside the medium the wave field can be decomposed into downgoing and upgoing waves and that evanescent waves can be neglected. We present a new derivation of Green's function representations which circumvents these assumptions, both for the acoustic and the elastodynamic situation. These representations form the basis for research into new Marchenko methods which have the potential to handle refracted and evanescent waves and to more accurately image steeply dipping reflectors.