High resolution fault analysis of the Vestnesa Ridge: a highly complex deep water fluid flow system in the east Fram Strait

Processes such as oblique mid ocean ridge spreading, glacial isostatic adjustment and slope instability provide a highly complex spatial and temporal record of stress in the Fram Strait. The Vestnesa Ridge is a contourite drift bounded by two slow spreading mid ocean ridges located beside a formerly glaciated margin. The total state of stress is difficult to separate into individual components therefore our focus is to ascertain whether there is a stress transfer from the deep crust into the shallow overlying (~200m) sedimentary cover. We use high-resolution P-cable 3D seismic volumes together with 2D seismic, to map deeper faults connecting with near surface deformation. We perform high resolution mapping of the ridge by examining the dip and strike of each distinct fault system. We use a pre trained 3D model to predict faults within each 3D volume and automatically extract faults at multiple intervals to capture temporal stress changes. To minimize noise, the model identifies faults based on edge preserved smoothing for a selection of peak frequencies. In our results we observe fault linkage between parallel faults that may become favourable locations for transtensional and transpressional stress expected in the strike slip regime predicted in the west of the ridge. Our results show that the east of the ridge has a dominant NW-SE fault strike and a present day tensile stress regime while towards the west, the NW-SE assemblage becomes less prominent and multiple fault systems dominate increasing the complexity of the system. We present a high detail comprehensive structural analysis of 3 study sites across the shallow ridge sediments and use our results to investigate differences in the strike and dip between sites to explore the influence of sedimentary faults and ridge geomorphology on the spatial evolution of seafloor seepage at a deep Arctic oceanic basin.