A coastal risk analysis for the outermost small islands of Indonesia: a multiple natural hazards approach

Coastal risk analysis is important for the sustainable development and resilience of small islands. Even though there is an increasing effort to develop risk analysis at the global scale, the integration of multi-hazard, exposure, and vulnerability for outermost small islands is still rare. This study is the first to address the coastal risk on the outermost small islands of Indonesia, located at the country's territorial edge. The methodology quantifies hazard, exposure, and vulnerability variables, and collating the indices into a risk matrix. The results identify the full range of risk levels on outermost small islands represented in the island dataset, providing different approaches of addressing adaptation based on island’s risk variables. Rote is identified with a Very High-risk level, while Makalehi has the highest hazard index, Bintan the highest exposure index, and Letti-Kisar the highest vulnerability index. Both coastal and geophysical hazards significantly influence risk, while economic land use impacts exposure. Infrastructure, including connectivity access and protection structures, plays a crucial role in vulnerability. The factors identified in this study, such as the highest hazard potentials, the most exposed variables, or the greatest vulnerability factors, could be used to craft policy recommendation that are designed and implemented to create island-specific adaptation strategies. In general, this study addresses a gap in current research, serving as a foundation for further investigation into coastal risk assessment. This study provides critical insights into the compounded risks faced by similarly outermost regions, offering transferable lessons for other developing archipelagic countries in enhancing their resilience.