Evacuation Guidelines and Safety Measures for Tokyo and Surrounding Areas

A Comprehensive Overview

In the event of a major eruption at Mount Fuji, residents in the zone from the mountain to Sagamihara, Kanagawa Prefecture, just west of Tokyo, are advised to evacuate immediately. This area, designated as Stage 4 on a four-stage classification scale, is projected to receive at least 30 centimeters of ash, posing significant danger.

For most other areas, the guidelines recommend staying indoors due to the anticipated disruption of electricity, transportation, and communication. These guidelines, compiled by a Cabinet Office panel on March 21, 2023, are based on the historical record of Mount Fuji eruptions, with the last major one affecting Tokyo occurring in 1707.

The 2020 estimates by the government's Central Disaster Management Council for a major Mount Fuji eruption similar to the one 300 years ago predict ashfall across eleven prefectures, including 3 cm near Shinjuku Ward in Tokyo and 30 cm in the zone extending to Sagamihara.

The four-stage classification system is designed for use in other areas prone to volcanic eruptions, such as Mount Usu in Hokkaido, Mount Asamayama in Nagano and Gunma prefectures, and Mount Aso in Kumamoto Prefecture.

Stage 4 residents are urged to evacuate to safer areas, while Stage 3 residents, projected to receive between 3 and 30 cm of ash, should be prepared for potential transportation disruptions and supply shortages. The guidelines recommend storing at least one week's worth of food, water, toilet paper, and other essential supplies.

Yosuke Miyagi, a researcher at the National Research Institute for Earth Science and Disaster Resilience, emphasizes the dangers of volcanic ash, highlighting its sharpness, potential for eye and respiratory damage, and ability to disrupt transportation and infrastructure.

Miyagi also warns that even a small amount of ash can render railways inoperable and cause power outages. The guidelines prioritize clearing major roads and railway lines, with an estimated 31 million cubic meters of ash needing removal. However, authorities face challenges in securing sufficient storage space for the removed ash.