TOKYO, KOMPAS.com – A sobering forecast for Japan’s capital: should Mount Fuji erupt with the force it displayed 300 years ago, Tokyo and its surrounding areas could face a blanket of volcanic ash reaching a thickness of 10 centimeters (approximately 4 inches) or more.
This stark warning comes from a specialized panel appointed by the Japanese government. Their comprehensive study, highlighting the potential impact and necessary mitigation strategies, was released on Friday, March 21, 2025, as reported by NHK.
The panel, comprised of leading volcanologists and disaster preparedness experts, emphasized the critical need for thorough mitigation measures, particularly given the dense population concentrated in the Tokyo metropolitan area and Kanagawa Prefecture. The sheer number of residents elevates the stakes significantly.
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The report acknowledges the impracticality of mass evacuation. “It is unrealistic for residents of Tokyo and surrounding prefectures to immediately evacuate the area,” the panel stated, recognizing the logistical challenges of relocating such a large population quickly.
Instead, for residents in areas expecting ash accumulation of less than 30 centimeters, the primary recommendation is to shelter in place. The panel advises residents to remain indoors in secure locations and stockpile at least two weeks’ worth of essential supplies, preparing for potential disruptions to daily life.
Local governments and businesses are urged to prioritize the maintenance and swift repair of vital infrastructure. Protecting these critical systems is paramount to ensuring the region’s resilience in the aftermath of an eruption.
However, for those residing in areas where ashfall is predicted to reach 30 centimeters or more, evacuation becomes a necessity. The panel specifically cautioned against the risk of wooden houses collapsing under the weight of wet, heavy ash, especially during rainfall.
Vulnerable populations, including patients requiring dialysis or intensive care, should evacuate as soon as ash thickness reaches 3 centimeters. This preemptive action is crucial, as even a relatively small amount of ash can trigger prolonged power outages, jeopardizing essential medical care.
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The panel also pressed the government to establish a robust information dissemination system capable of providing real-time volcanic ash forecasts. Alongside this, they stressed the urgent need to prepare effective evacuation routes, ensuring a smooth and organized response during a crisis.
Professor Emeritus Fujii Toshitsugu of the University of Tokyo, who chairs the panel, pointed out that Japan hasn’t experienced a volcanic eruption with such widespread ash dispersion in the past century. This lack of recent experience underscores the need for proactive planning and preparation.
“However, it is important for Japan to begin preparing for such a disaster,” he concluded, highlighting the importance of readiness in the face of potential catastrophe.
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Ringkasan
A Japanese government panel has issued a warning that a Mount Fuji eruption similar to the one 300 years ago could blanket Tokyo and surrounding areas with significant volcanic ash. The panel emphasizes the impracticality of mass evacuation for Tokyo’s large population, recommending that residents in areas with less than 30 cm of predicted ashfall shelter in place with two weeks of supplies.
For areas expecting heavier ashfall (30 cm or more), evacuation is necessary due to the risk of collapsing buildings, especially wooden structures. Vulnerable populations should evacuate once ash thickness reaches 3 cm, and the panel urges the government to establish real-time ash forecast systems and prepare effective evacuation routes. The lack of recent large-scale ash dispersion events in Japan highlights the need for proactive disaster preparedness.