Characteristics of Coseismic Uplift on Ports for Great Earthquakes Along the Nankai Trough: Preparing for Advance Countermeasures

Advance countermeasures are crucial to address future great earthquakes along the Nankai Trough. Damage caused not only by strong ground motion and tsunami but also by coseismic uplift was reported following previous major earthquakes. If coseismic uplift causes a port to cease to function, there is concern regarding the impact on fisheries and logistics, and whether it can function as a disaster-management base, e.g., for transporting emergency goods and evacuating residents. To understand the characteristics of coseismic uplift on ports, we analyzed coseismic uplift on ports for great earthquakes along the Nankai Trough. Specifically, considering the variety of great earthquake occurrences along the Nankai Trough, we analyzed the amount and likelihood of coseismic uplift for more than 900,000 occurrence patterns and discussed the extent of port functioning as a disaster-management base. This study revealed that, when an M 9-class earthquake occurs, some emergency relief ships may not be able to berth at ports positioned as disaster-management hubs. Additionally, when an M 8- to M 9-class earthquake occurs, some ports may not function to the same extent as before. The results of this study and related discussions, such as ports’ function as disaster-management bases and the impact on fisheries and logistics, are expected to contribute to the advancement of effective preparedness and countermeasures for ports against future great earthquakes along the Nankai Trough.