Balancing profitability and resilience to earthquake-induced isolation: A multi-objective optimization for drone depot location

Drone delivery networks possess a unique dual-use potential, enhancing commercial profitability during normal operations while providing critical logistics support for isolated communities during disasters. However, relying solely on market mechanisms fails to secure resilience in high-risk, sparsely populated areas, making a Public–Private Partnership (PPP) framework essential. This study develops a multi-objective optimization model to serve as a quantitative baseline for designing such partnerships. By explicitly integrating a physics-based risk assessment that connects seismic shaking and topography to landslide probability and road failure, ultimately estimating community isolation risk, we visualize the trade-off between private profitability and public safety. Applying the model to a case study in Japan, we derive a Pareto frontier demonstrating that a significant reduction in isolation risk is achievable with a relatively minor sacrifice in commercial profit, thereby helping to quantify the necessary public subsidy. Furthermore, our sensitivity analysis reveals that as the investment scale expands, the optimal strategy shifts from a general compromise to a specialized approach. This finding provides a theoretical basis for a spatial division of roles within PPPs, where the private sector operates profitable urban depots while the public sector supports resilience-oriented facilities in remote areas.