Earthquakes in Osaka

Osaka carries a high level of seismic risk, driven both by active faults running directly through the Kansai region and by the ever-present threat from offshore megathrust zones. The Uemachi and Arima-Takatsuki fault systems cut close to the metropolis, while the looming Nankai Trough offshore is capable of producing catastrophic magnitude 8-plus earthquakes that would shake Osaka strongly. Large parts of the city are built on soft reclaimed and alluvial ground that amplifies shaking, adding to the danger.

The most recent damaging event was the magnitude 6.1 earthquake of 18 June 2018, which struck at shallow depth beneath northern Osaka during the morning rush hour. It killed several people, injured hundreds, and disrupted rail, water and gas services across the region, exposing the vulnerability of older concrete-block walls and ageing infrastructure. The quake reinforced official warnings about the far larger Nankai Trough earthquake that experts consider likely within the coming decades.