Assessing Megathrust Earthquake Probability, Public Stress, and Government Policy Recommendations in the Mentawai-Siberut Region, Indonesia

This study aims to assess seismic hazards and develop effective mitigation strategies for the Mentawai-Siberut region in Indonesia. The research uses quantitative and qualitative methods to analyze historical seismic data, predictive models, and stakeholder perspectives. The quantitative analysis includes seismic hazard estimation using the Gutenberg-Richter formula, ground movement analysis based on GMPE, and time interval calculations to forecast future earthquakes. Qualitative methods involve Policy Network Theory to explore the roles and interactions of various stakeholders in disaster management, including government agencies, theIndonesian Archipelago Youth Association (NGOs), local communities, and academic researchers. Findings reveal significant seismic activity in the area, with historical earthquakes of magnitudes 8 and 9 occurring at intervals of 18 to 232 years. Predictions suggest a potential magnitude 8 earthquake around 2083, with a megathrust event likely around 2123. The study also identifies economic costs and losses, with damage from a megathrust estimated between USD 1.5–2.5 billion and 10-20 billion, including destroyed homes and displaced populations. Challenges include infrastructure limitations, logistical constraints, and enhancing disaster preparedness and response. The study emphasizes the importance of improving infrastructure, strengthening disaster preparedness, and updating early warning systems. Effective collaboration among stakeholders and integrating local knowledge into disaster management strategies are crucial for enhancing regional resilience. Recommendations include completing infrastructure projects like the Trans-Mentawai Road, increasing community engagement, and utilizing scientific data for evidence-based policymaking. Addressing these recommendations and limitations is essential for developing a robust disaster management framework to mitigate regional seismic risks.