Litho-structural controls on Quaternary landslide distribution in the Rangitikei hill country, North Island, New Zealand.

The aim of this research is to investigate the influence of stratigraphy and structure on the development of present-day topography in the Rangitikei hill country. This is achieved by (1) comparing a new inventory of deep-seated Late Quaternary relict landslide zones to the hydraulic, physical and structural properties of the Whanganui Basin fill, (2) analysing the proximity of landslides to structures and rivers, and (3) exploring the relationships between geology and slope morphology. Analysis suggests postglacial incision and daylighting of the Whanganui Basin fill is a primary control on landslide distribution, providing the necessary conditions upon which a range of triggering mechanisms operate. Faults display a clear relationship to landslide frequency, suggesting earthquakes are possibly an important triggering mechanism. Landscape evolution involves inversion and denudation of alternating coarse and fine-grained sedimentary units. Frequent, shallow landslides dominate on steep, northern scarp slopes, and deep-seated rock planar slides dominate on gentle, southern dip slopes. [ABSTRACT FROM AUTHOR]