Large-scale geolocation data reveal evacuation behaviour during the 2024 Noto Peninsula earthquake and tsunami

Abstract On 1 January 2024, the Noto Peninsula earthquake generated a devastating tsunami that struck coastal areas within several minutes, yet resulted in few tsunami casualties. Despite its importance, the cause of this unexpectedly low human loss remained unclear, as conventional surveys were hindered by the limited access and the presence of many visitors during the holiday. Here we reveal evacuation behaviour during the 2024 Noto Peninsula tsunami using large-scale geolocation data collected from a smartphone app. We find that the evacuation was extremely fast, occurring within 2–6 min after the origin time. Additionally, the long-term analysis of the data reveals that people started returning to the coastal area 20–100 min after the origin time, which was long before the downgrading and cancellation of the tsunami warnings. These results highlight the utility of the geolocation data for evacuation surveys, which addresses the limitations of conventional evacuation surveys.