Heterogeneous Sediment Input at the Nankai Trough Subduction Zone: Implications for Shallow Slow Earthquake Localization

Subducted sediment plays a key role in modulating pore pressure and seismic behavior at subduction zones. We investigated the character of incoming sediments to test how basement variations relate along-strike changes within accretionary prism plate boundary conditions Nankai Trough. High-resolution data reveal for first time presence countourite mounded drifts Shikoku Basin. These features have probably introduced permeability heterogeneities into an otherwise homogenous mud-dominant unit. Additionally, we found that normal faults this unit are more extensive than previously documented, which enhances fluid transport. The wedge taper is correlative with thickness facies turbidite thickness. This may be due associated contourite deposits faults, or absence thick deposits. Turbidite can either aid drainage margin where they not confined by topography, contribute high pressures less permeable mudstone topography. When subducted, localized compartments excess provide necessary slow slip behavior. determined likely related subducting topographic characteristics, vary on local (<10 km) scale.