What drives landslide risk? Disaggregating risk analyses, an example from the Franz Josef Glacier and Fox Glacier valleys, New Zealand

Abstract. We present a quantitative risk analysis (QRA) case study from the Kā Roimata o Hine Hukatere / Franz Josef Glacier and Te Moeka Tuawe Fox valleys, on west coast of South Island, Aotearoa New Zealand. The glacier valleys are important tourist destinations that subject to landslide hazards. Both contain actively retreating glaciers; experience high rainfall; proximal Alpine Fault, which is major source seismic hazard coast. considered life safety rockfalls, soil/rock avalanches, flows either seismically triggered or occur aseismically. To determine range in values dominant contributing variables risk, we modelled nine different scenarios where incrementally changed used model account for underlying uncertainty. represent our central estimate e.g. neither optimistic nor conservative, through upper risk. include these estimates impact time-variable factors, such as recently reactivated landslide, have had locally increasing time-elapsed since last earthquake nearby Fault. disaggregated results drivers highlighted importance considering dynamic changing contributions aseismic versus landslides. A detailed understanding each valley most efficient appropriate management decisions.