Fluid Drainage Networks and Physical Properties of the Cascadia Margin off Central Oregon from Advanced Seismic Imaging Using Multi-Scale Data (Streamer, OBS, and Seafloor Nodes)

About This Grant

The subduction zone offshore Cascadia has produced large earthquakes in the past. Fluids are thought to play an important role in fault slip on the subduction zone interface, and seafloor fluid venting is widespread on the Cascadia margin. This project will use cutting edge techniques on a unique dataset that includes a dense array of ocean bottom nodes to study the Cascadia subduction zone. The results will include high-resolution images of the subseafloor fluid drainage network and should help improve geohazard risk assessment of the region. This project will support an early career scientist serving as lead Principal Investigator. At the Cascadia margin, seafloor fluid venting is widespread, with geochemical evidence suggesting that fault and fracture networks in some areas facilitate fluid drainage from as deep as the décollement or even the subducting plate. This study will characterize seismic and physical properties along a profile offshore central Oregon. Seismic data includes ultra-long streamer (12 km) multichannel seismic data, wide-angle data from ocean bottom seismometers deployed at ~9-km spacing, and a dense array of 107 ocean bottom nodes deployed at 500-m spacing. The project will produce high-resolution images and physical property models that will advance understanding of the links between fluid drainage networks, strike-slip faults and megathrust seismogenic properties. The study will leverage use of an existing dense ocean bottom seismic dataset acquired using state-of-the-art industry techniques. This project will facilitate the growth of an early career scientist serving in his first role as lead Principal Investigator. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.