The Chiba Prefecture government updated its large-scale earthquake damage projections for the first time in 10 years, forecasting a worst-case scenario of 57,200 deaths [1].
These updated figures serve as a critical baseline for revising disaster countermeasures and informing residents about potential risks. By integrating the latest seismic and tsunami scenarios, the prefecture aims to improve evacuation plans, and infrastructure resilience in coastal areas.
The most severe projection involves a magnitude 8.5 earthquake occurring in the waters east of the prefecture [1]. This event is expected to trigger tsunamis reaching a maximum height of 12.8 meters [1]. The resulting devastation would lead to the projected death toll of approximately 57,200 people [1].
Other scenarios were also detailed in the update. In a scenario involving a magnitude 7.3 earthquake, the government projects approximately 2,400 deaths [1]. This figure represents an increase of 300 deaths compared to the previous projections made a decade ago [1].
Additionally, the government analyzed a scenario based on the scale of the 1923 Great Kanto Earthquake. Under those specific parameters, the projection estimates approximately 920 deaths [1].
The updates focus heavily on the eastern regions of the prefecture, including Isumi City, where the risk of high-reaching tsunamis is most acute [1]. The government said the updates are necessary to provide residents with the most current information for their safety.
“Worst-case scenario of 57,200 deaths”
The significant increase in projected fatalities and the specific height of 12.8 meters indicate that previous safety margins may have been insufficient. By updating these figures, Chiba is acknowledging that current evacuation routes or sea walls may not protect the population against an M8.5 event, likely triggering new investments in coastal defenses and more aggressive public awareness campaigns.
