# **OBN acquisition design**

Acquisition design generally consists of building a realistic synthetic model of the targeted area, computing datasets in this model for different acquisition scenarios, and applying the seismic imaging workflow on different datasets. During WIND, we aim to study the optimal design of sparse areal OBN acquisition through the solving of an optimization process. We plan to use the theory of diffraction tomography to formulate the optimization problem and find the acquisition providing the best compromise between deployment effort, resolution and sampling. To perform this acquisition design analysis we will use both a well-documented OBC dataset from the north sea that will be decimated to mimic a sparse OBN dataset and the

**GO_3D_OBS benchmark** for deep crustal exploration (see Figure below). In the first case, we already apply FWI on the full dataset (see FFWI menu). Hence, the FWI results will be used as a reference to assess the footprint of sparse acquisition.

a) Target of the GO_3D_OBS velocity model. b) Sketch of a sparse node deployment on the seabed. The wavenumver vector sampled at a given position of the subsurface by a source-receiver pair and one frequency is illustrated. The modulus of this wavenumber vector is controlled by both frequency and scattering angle. From this relationship it is easy to perform an illumination analysis to check the wavenumber bandwidth covered by the acquisition as well as the sampling of this bandwidth.