A Japanese government panel has issued new safety guidelines for the Greater Tokyo region amid concerns that Mount Fuji could erupt. The expert panel, convened by the Cabinet Office, released recommendations on Friday, advising the region’s 44 million residents to stay indoors unless ashfall becomes severe.
Authorities have urged municipalities and households to maintain emergency supplies, including food and water, to prepare for a potential eruption of Japan’s highest peak. Mount Fuji, standing at 3,776 meters (12,389 feet), last erupted in 1707, covering parts of modern-day Tokyo with a thick layer of volcanic ash.
In a worst-case scenario, experts warn that a major eruption could deposit more than 30 centimeters (12 inches) of ash over Tokyo, located approximately 100 kilometres (62 miles) northeast of the volcano. Such an event could disrupt daily life, impacting infrastructure, transportation, and public safety.
Four-Stage Ashfall Alert System
To help residents understand the risks, officials have introduced a four-stage alert system based on ash accumulation:
Stage 1: Ashfall under 3 cm (1.2 inches), with minor disruptions like train delays.
Stage 2: Ashfall between 3-30 cm (1.2-12 inches), where emergency restoration of utilities like electricity remains possible.
Stage 3: Ashfall of 3-30 cm combined with power outages that cannot be quickly restored. Local governments may consider evacuations.
Stage 4: Ashfall exceeding 30 cm (12 inches), leading to structural damage and widespread evacuations.
The panel cautioned that wooden buildings, especially in urban areas, could collapse if heavy ash accumulates and mixes with rainfall.
Historical Precedent: The 1707 Eruption
Mount Fuji’s last recorded eruption in 1707 lasted 16 days, blanketing present-day central Tokyo with a 4 cm (1.5 inches) layer of volcanic ash. If a similar event were to occur today, it could severely impact Japan’s densely populated capital and surrounding regions.
Authorities Call for Public Awareness
While there is no immediate sign of an eruption, officials stress the importance of public preparedness. Local governments and emergency services are reviewing evacuation plans, and residents are encouraged to stay informed through official channels.
Mount Fuji, which straddles Yamanashi and Shizuoka prefectures, remains an iconic yet potentially dangerous natural landmark. Scientists continue to monitor its seismic activity, and authorities are ready to implement safety measures if warning signs intensify.
AloJapan.com