Ambient Noise Tomography from the UPFLOW Seafloor Array in the Atlantic

We use 14 months of continuous recordings (June 2021 - August 2022) from the UPFLOW seafloor passive seismic array experiment. The experiment included 50 broadband ocean bottom seismometers (OBS) deployed in the Azores-Madeira-Canary Islands region, with an average interstation distance of ~130 km. The availability of both OBS and land stations makes this experiment ideal for determining the best approach to extract reliable empirical Green's functions (EGFs) and construct 3D shear-wave velocity models. The measured dispersion curves are used in a Bayesian inversion to obtain a series of 1D shear wave velocity models, which are then interpolated to construct a 3D model of the region.  We present the EGFs and dispersion measurements obtained using different techniques, ranging from distinct cross-correlation methods to different stacking procedures. We also show preliminary phase and group velocity maps and a preliminary 3D shear-wave Earth velocity model. The 3D upper lithosphere images are compared with the main geological structures of the Azores and Madeira oceanic region. Moreover, we compare our new images with previous global and regional tomography models and discuss the differences introduced by the UPFLOW data.