Katherine Yates

Slope failure is a significant natural hazard for Aotearoa, often aggravated by seasonal wet weather or earthquake activity. These hazards pose a risk to life, infrastructure and property. This project will explore slope failures in a type of soil known as loess which is widespread in the South Island of New Zealand.

Dr Yates by a cut loess slope. Image: supplied

Loess is a problematic soil. It forms from compacted, windblown sediments and is readily recognisable as thick, pale yellow layers in cliffs and roadcuts. While loess appears safe and stable in dry conditions, its strength significantly diminishes when wet or disturbed, at times leading to catastrophic slope failure. With climate change expected to increase rainfall intensity and frequency in the Shaky Isles, the implications of wetter loess on future slope stability needs to be understood on its own and in conjunction with earthquake shaking.

This research will address knowledge gaps in the relationship between saturation of loess and seismic slope stability. Initial laboratory tests will assess the strength of loess soils under simulated earthquake loading, with subsequent tests adding an artificial rainfall component partnered with ground shaking. Dr Yates findings will provide much needed knowledge about the interaction between these two significant slope-failure triggers, and how slope stability in Aotearoa might evolve as our climate changes.

Understanding our natural hazards and the associated risk they pose to the built environment is critical for decision-makers and public.  Dr Yates research will give a better understanding of the potential risks associated with simultaneous hazards – including vulnerable soils, more intense droughts and floods, and continuing seismicity – to inform about future land use planning and slope management.