February 12, 2025
TOKYO – The Internal Affairs and Communications Ministry will designate in advance local governments that will dispatch relief personnel to other prefectures in the event of a massive earthquake in the Nankai Trough, The Yomiuri Shimbun has learned.
The pre-chosen governments would send personnel to 10 prefectures expected to suffer severe damage in the event of a Nankai Trough quake. The aim of the policy is to enable local governments that will provide support, and the prefectures expected to receive help, to conduct joint disaster drills and other preparations. They would also share information on the expected damage and what kind of aid will be necessary.
The ministry hopes these steps will enable assistance to be provided swiftly in the wake of a Nankai Trough quake. It plans to formalize the decision at a meeting attended by the relevant local governments and other interested parties on Wednesday, and the policy is expected to be implemented from April.
A Nankai Trough earthquake refers to a seismic event that originates from the Nankai Trough, which extends from off Shizuoka Prefecture to off Miyazaki Prefecture. There is estimated to be an about 80% chance of a quake with a magnitude of 8 or 9 occurring in the next 30 years.
According to a 2019 estimate by the Cabinet Office, the number of deaths and missing persons could reach 231,000, while up to 2.09 million buildings could collapse or burn.
In March 2018, the internal affairs ministry launched a system to send local government personnel to areas hit by disasters. Under this system, the municipalities that send or receive personnel are decided after a disaster occurs.
Following the Noto Peninsula Earthquake in January 2024, staff from 63 municipalities were dispatched to 18 cities and towns mainly in Ishikawa Prefecture to support operations such as the management of evacuation shelters and investigating the damage to houses.
However, in many cases, the support staff were unfamiliar with the geography of the disaster area, and the local governments affected by the disaster were unable to decide what kind of help they should request, causing confusion on-site.
The government has estimated that if a Nankai Trough quake occurs, 707 cities, towns and villages in 29 prefectures could be hit by a tremor with a seismic intensity of lower 6 or higher on the Japanese scale, or by a tsunami at least 3 meters high.
As a result, the internal affairs ministry has decided to choose ahead of time which prefectures will be responsible for providing immediate support to the 10 prefectures expected to suffer extensive damage. The 10 prefectures to receive support are Shizuoka, Aichi, Mie, Wakayama, Tokushima, Kagawa, Ehime, Kochi, Oita and Miyazaki, all of which are located along the Pacific coast.
The prefectures that will provide support were selected mainly from areas along the Sea of Japan and the northern Kanto region, taking into account the expected scale of damage, distance and the existence of support agreements that have been concluded individually.
Toyama Prefecture will provide support to Shizuoka, Fukushima to Aichi, Fukui to Mie, Saitama to Wakayama, Tottori to Tokushima, Tochigi to Kagawa, Gunma to Ehime, Shimane to Kochi, Saga to Oita, and Nagasaki to Miyazaki.
Multiple prefectural governments and municipalities were selected to offer support to prefectures that are expected to suffer particularly heavy damage among the 10 – Shizuoka, Aichi, Mie, Tokushima and Kochi.
Tokyo, Kanagawa and Osaka were not chosen to provide support, because they include areas that could be affected by a Nankai Trough quake.
From fiscal 2025, the paired prefectures will work together on activities such as joint disaster drills, inspections of areas expected to be hit by the massive quake, and confirmation of transportation routes for providing support. They will also exchange lists of employees who have expertise in areas such as civil engineering, waste disposal and evacuation center management, with the aim of ensuring smooth operations.
“It’s difficult to act quickly at disaster sites unless the people who provide support and those receiving support understand each other’s circumstances,” said Saneyuki Udagawa, a researcher at the National Research Institute for Earth Science and Disaster Resilience. “Additional measures will also be needed, such as interviewing local governments that have experience of providing support at disasters to learn about effective support methods.”