Slope Failure, Tectonics, and Gas and Fluid Expulsion on the Southern CascadiaContinental Shelf and Slope: Effects on Seafloor Geomorphology

摘要

The objective of this project is to evaluate the role of fluid flow,overpressuring, and gas migration in the creation of failure features on the seafloor of a tectonically active continental margin. This project addresses questions about the lateral and vertical extent of detectable gas and gas-related structures in the subsurface, the regional distribution of failure features, the locations of overpressured fluids in the subsurface, and how the structural geology of this region affects the locations of gas and fluid migration pathways and expulsion sites. Observations and hypotheses based upon remote sensing techniques (industry-quality multichannel seismic, high resolution multichannel seismic, high resolution single channel seismic, acoustic reflectivity, high resolution sidescan, high resolution bathymetry) are ground-truthed with direct observation and sampling via use of a remote operated vehicle (ROV). These observations form the basis for modeling the relationship between gas-charged fluids and slope failure. Fulfillment of these objectives will allow us to obtain a better understanding of the dynamic processes occurring on the southern Cascadia continental shelf and slope, and ultimately help address how sediment is transported from the shelf to upper slope, and from the upper slope to abyssal depths.