Port disruptions entail substantial costs—the Tohoku tsunami of 2011 damaged ports and vessels, amounting to around $12 billion. Still, the subsequent disruptions in port operations led to a staggering daily loss in seaborne trade valued at approximately $3.4 billion. Given that over 80% of the world’s trade is conducted via shipping, interruptions in the global port network can profoundly impact international commerce. Yet, in the planning and structural design of ports, the threat posed by tsunamis is often overlooked. This neglect is attributed to the rarity of tsunamis and the absence of effective methods for assessing the associated risks.
In light of these challenges, a team of researchers has developed a framework designed to assess the risk of tsunamis to seaports and the broader global port network. This framework predicts the economic losses that may result from disruptions at ports. It examines the broader effects on the worldwide network, including implications for shipping routes and ports that do not suffer direct damage.
The research was spearheaded by Constance Chua, a postdoctoral researcher at the International Research Institute of Disaster Science (IRIDeS) at Tohoku University, with the collaboration of Professor Fumihiko Imamura, Associate Professor Anawat Suppasri, and Professor Adam Switzer from Nanyang Technological University.
“Our analysis focused on a hypothetical tsunami in the South China Sea, triggered by seismic activity along the Manila Trench,” explained Chua. “We also took into account the impact of rising sea levels on tsunami conditions.”
The study extensively evaluated 104 scenarios with contributions from international experts across multiple disciplines. These experts included Dr Tanghua Li, a geophysicist at the Earth Observatory of Singapore who specialises in sea-level rise modelling for Asia; Research Professor Qiang Qiu, an authority on tectonic geodesy at the Chinese Academy of Sciences focusing on the Manila Trench; and Professor Linlin Li, an expert in tsunami modelling from Sun Yat-sen University. Their collective expertise allowed the team to incorporate the most current data and models on various hazard components, crafting scenarios that closely resemble potential real-world events.
The study’s findings revealed that a tsunami from the Manila Trench could affect up to 11 international seaports under sea-level conditions and as many as 15 by the year 2100. Some ports might be closed in the worst-hit areas for over 200 days. However, the duration of port closures did not necessarily correlate with the most significant economic losses. Ports handling larger volumes of cargo annually were more vulnerable to financial detriment. The ports in Hong Kong, Manila, and Kaohsiung suffered the most significant trade losses in all the scenarios considered.
Chua further noted that a tsunami from the Manila Trench could have a more severe impact on global trade than the devastating events of the 2004 Indian Ocean tsunami and the costly 2011 Tohoku tsunami. “As South China is home to some of the busiest ports and sea lanes in the world, the number of shipping routes affected would surpass those in previous tsunami events significantly,” she said. “Given the historical neglect of tsunami impacts in safety planning, our findings are crucial for helping stakeholders better prepare for future disasters.”
More information: Constance Ting Chua et al, An approach to assessing tsunami risk to the global port network under rising sea levels, npj Natural Hazards. DOI: 10.1038/s44304-024-00039-2
Journal information: npj Natural Hazards Provided by Tohoku University