Subsurface structures of the Tuaheni Landslide Complex at the upper slope of the northern Hikurangi margin, New Zealand, revealed by seismic attribute analysis

Abstract Tuaheni Landslide Complex, located on the upper slope of the northern Hikurangi margin in New Zealand, is a unique location to study slow slip creep-like deformation and seafloor failure, as well as their possible relationship to the presence of gas hydrate, cold seeps, and fluid migration. Based on the visual interpretation of seismic data, sometimes it is very difficult to identify various subsurface structures and tectonic features. We study certain seismic attributes namely reflection-strength, instantaneous frequency, instantaneous phase, and Hilbert Transform in the Tuaheni Landslide Complex and observe that these attributes play a very important role to identify and interpret various subsurface geological features, which are not visible in the seismic sections. These seismic attributes nicely illustrate the fluid migration pathways, the decollement of the sediment slide, the base of the debris flow, the base of the deformed sediment and gas migration, etc. along two perpendicular seismic profiles crossing the well Site U1517 of IODP Expedition 372. The possible role of tectonic activity and seafloor slope failure due to gas hydrate dissociation and vice versa are clearly visible through fluid-filled weak zones in the seismic attribute volumes.