Japanese government disaster experts have prepared an advance assessment plan indicating that a major earthquake directly striking Tokyo could leave over 8.4 million people stranded, risking chaos if they all try to return home simultaneously, and also affecting rescue operations.
On 19 Dec 2025 GMT+7, Japanese government disaster experts revealed the latest advance assessment, warning that a large earthquake directly affecting Tokyo could leave as many as 8.4 million people unable to travel back home.
This assessment covers Tokyo and nearby prefectures including Kanagawa, Chiba, Saitama, and Ibaraki. In Tokyo alone, the number of stranded people could reach as high as 4.8 million.
The report also notes that about 1.6 million people might be unable to shelter at their workplaces or schools due to building damage or ongoing evacuations. At the same time, visitors from outside the Tokyo metropolitan area, including tourists and foreign business travelers, could number up to 880,000.
Experts warn that if people try to return home all at once, severe congestion will occur, increasing the risk of accidents and injuries, and potentially causing crowds to overflow onto streets, obstructing emergency vehicles and rescue teams.
Professor Hiroi Yu of the University of Tokyo stated that moving people after a large disaster is more difficult than expected. He emphasized that once in a safe location, people should not rush to return home immediately. He advised citizens to prepare multiple safety confirmation methods rather than relying solely on phones or social media, recommending the use of Japan's emergency message service and contacting relatives or acquaintances outside the affected area to reduce panic and risk during major incidents.
Source: NHK