Recent geological surveys have revealed a new active fault measuring 60 to 70 kilometers long along the coast of the Kunisaki Peninsula in Oita Prefecture, northeastern Kyushu, Japan. The Japanese government previously estimated an 80% chance of a magnitude 8 or greater earthquake occurring in the South China Sea trench within the next 30 years.

This newly identified fault may not trigger a tsunami, but it could still lead to earthquakes of magnitude 7 or higher. In response, the Oita Prefecture government convened an expert meeting to include this fault in their earthquake disaster risk assessment, reinforcing their disaster preparedness strategy. Reports indicate that the fault is nearly linear due to the lateral compression of tectonic plates, making it less likely to generate a large tsunami, but its activation could still result in significant seismic events.

The authorities emphasize the need to integrate this new data into the national earthquake disaster prediction system. They plan to update assessments in 2026 to provide local governments and residents with timely warnings and evacuation guidance. Experts noted that past oversight in including active fault data in predictive models, such as during the 2024 Noto Peninsula earthquake, resulted in inadequate disaster response measures. The Oita Prefecture government aims to mitigate future risks by proactively incorporating the Kunisaki Fault into their risk assessments.