Introducing Hōretireti Whenua / Sliding Lands: integrating social science into nationally applicable landslide risk models for Aotearoa NZ

Much of Aotearoa NZ is hilly or mountainous and experiences high rainfall and frequent earthquakes. Consequently, landslides are an existing or potential hazard in many parts of the country, with the risk from landslides likely to increase with climate change. Cyclone Gabrielle (February 2023) highlighted the devasting impact of such landslides on people, property, and infrastructure networks. To increase the resilience of Aotearoa NZ to landslide-induced disasters, we need robust and consistent information that creates an evidence base to inform effective decision-making in the management of landslide risk nationwide, considering planners, policy-makers, emergency managers and government officials, lifeline and infrastructure managers, as well as other technical experts (e.g., engineers). This decision-relevant information needs to include when and where landslides occur, who and what they may impact, and how people, businesses, and communities perceive, mitigate, and respond to this hazard.

In this presentation we will detail how the new Hōretireti Whenua / Sliding Lands five-year Endeavour programme will integrate social science into the development of new probabilistic and scenario-based, nationally applicable, landslide hazard and risk models that can incorporate climate change scenarios. We will first introduce the vision for the integrated landslide risk models which will include: a) probabilistic models of landslide susceptibility considering earthquakes and rain, b) landslide runout models considering diverse landslide types, c) the multi-hazard risk modelling tool (RiskScape) to integrate hazard and vulnerability model components into forecast models, and d) the MERIT Tool to quantify the socio-economic impact of landslide hazards.

We will then present initial results from the first phase of associated social-science research that has mapped the range of decision maker needs for susceptibility, impact, and risk information, considering different decision sectors, demands, and timescales. Developed from this, a set of user personas and decision-scenarios will inform the effective communication of landslide risk across stakeholder groups, as well as inform effective application of the landslide risk models into decision-making for short-term risk management and long-term resilience. We will also present plans to investigate how individuals and organisations conceptualise landslide phenomena, models, and vulnerabilities using research techniques such as mental models and influence diagrams; with a view to integrating findings to not just improve communication of model outputs, but to also enhance decision-makers understanding of the national risk models. Through this we aim to increase effective uptake of these risk models into stakeholder decision-making across diverse organisations and sectors.