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We conducted a feasibility study on the processing of converted PS waves for an OBN (ocean bottom node) acquisition parameterised for PP data only. The PS seismic data was preconditioned and prepared as input for tomographic iterations to update the Vs velocity. Available geotechnical measurements were combined with an empirical model to construct the very shallow Vs velocity from the water bottom up to 200 m. From 200 m to the basement, the initial VS model was built using a predefined conversion pattern using the legacy PP velocity. After several tomographic steps, an initial set of images, migrated with Kirchhoff algorithm, presented several identifiable PS events in the PP volume. Refinements of Vs field, conducted by PP-PS correlation, improved the quality of PS data, mainly below the salt layer. Finally, partial stacks served as input data to a joint PP-PS elastic inversion test which resulted in a S impedance volume much closer to well data than the one derived from inversion of PP data only.