AIR establishes first post-Tohoku view of Japanese quake risk

Modelling firm, AIR has released a model update re-examining Japanese earthquake risk following Tohoku, including insights into the risks posed by tsunamis and liquefaction.

Commenting on the implications of Tohoku, Dr. Jayanta Guin, senior vice president of research and modelling at AIR Worldwide said: "The Tohoku event had important implications for our understanding of seismic risk in Japan and has also highlighted the importance of explicitly modeling earthquake-associated perils like tsunami and liquefaction."

According to AIR, “the updated earthquake model features an improved understanding of the seismicity on the Kanto Plain, home to some of the largest concentrations of exposure, including Tokyo. The new model also reflects a more thorough understanding of subduction zone segmentation and the possibility of multi-segment ruptures as well as a new formulation of plate geometry where the Pacific and Philippine plates interface beneath the Kanto Plain.”

The model updates also pay closer attention to the implications of tsunami events associated with major earthquakes. The revised model “captures both the complex nature of a tsunami's development and its dynamic behaviour as it nears the coast and comes on shore. AIR's tsunami damage functions not only account for inundation depth, water velocity, and debris but also take into consideration Japan's extensive defence system, including the probabilistic failure of levees due to the force of moving water,” according to the report.

Tohoku sparked considerable work in the field of seismology, with developments in AIR models incorporating “new findings into a robust, scientifically sound, and extensively validated model, providing clients with a forward-looking view of earthquake risk assessment in Japan."