AjwAsahi

With the official opening of climbing season being July 1, local and tourism officials near Mount Fuji have always steered the focus this time of year on tourism and visitors, and not on a possible eruption.

After last year’s Great East Japan Earthquake, however, they realize that they cannot avoid the threat any longer.

“The Great East Japan Earthquake demolished our belief that eruptions of Mount Fuji will not take place in our lifetime.

Awareness of the companies (in the local sightseeing industry) is changing,” said Yukichi Ueno, director of the Fujigoko Tourist League, which is made up of sightseeing-related companies in Yamanashi Prefecture.

The Shizuoka prefectural government has begun to study the possibility that a huge earthquake that could occur along the Nankai Trough in sea areas south of Japan would lead to the eruption of the 3,776-meter mountain.

In this fiscal year that started in April 2012, the Shizuoka prefectural government began to review for the first time in 11 years the estimated damages from a possible Tokai earthquake that could occur in the near future in or around the prefecture.

In that review, the prefectural government is considering the possibility that a Tokai earthquake occurs simultaneously with a Tonankai earthquake and a Nankai earthquake, both of which could take place along the Nankai Trough stretching from the prefecture to the west.

In addition, it is also studying the possibility that the simultaneous occurrence of the three earthquakes causes huge temblors that could lead to an eruption of Mount Fuji.

Since the Hoei eruption in 1707, Mount Fuji has not blown its top. However, the Shizuoka prefectural government is assuming the worst-case scenario in the event of the simultaneous occurrence of Tokai, Tonankai and Nankai earthquakes.

In that scenario, relief goods do not arrive from western Japan and assistance does not come from the Tokyo metropolitan area either, as the area is blanketed with falling ash from the eruption.

There have been cases in which a huge earthquake leads to eruption of a mountain. For example, the Hoei eruption took place 49 days after the Hoei Earthquake, with a magnitude of 8.6.

The Shizuoka prefectural government has asked the neighboring prefectures of Yamanashi and Kanagawa to jointly set up a council to work out wide-ranging evacuation plans in the event of a Mount Fuji eruption.

Meanwhile, the Yamanashi prefectural government has backtracked from its disaster preparedness plans that once stated the necessity of having to deal with an eruption of Mount Fuji is small. It deleted the description when it reviewed the plans in December last year.

Instead, it added plans for evacuating residents on buses. It is believed that talking about a possible Mount Fuji eruption openly became a forbidden subject after a book was published in 1982. In that book, a retired official of the Japan Meteorological Agency predicted that Mount Fuji would erupt in September 1983.

In the summer 1983, the number of tourists to areas around Mount Fuji drastically decreased, causing serious financial damage to local sightseeing industries. Yamanashi Prefecture alone suffered more than 300 million yen (about $3.8 million) in lost revenues.

As a result, the city government of Fujiyoshida in Yamanashi Prefecture even considered filing a lawsuit against the book’s author and publisher.

In 2004, the central government released a hazard map, which showed not only places of possible new craters but also areas that could be damaged by lava flows and volcanic rocks. However, discussions on possible damages did not progress among local governments.

After the March 11, 2011, disasters, the attitudes of local governments and people changed dramatically. Still, locals whose livelihoods depend on Mount Fuji tourism have strong concerns over the possible spread of baseless fear-mongering.

“If scholars or other experts say various things (about a possible eruption of Mount Fuji), our customers will be worried. I oppose the idea that local governments and other organizations promote measures to deal with possible eruptions,” said a man who operates a sightseeing-related business on the fifth station of Mount Fuji.

Meanwhile, in the Tokyo metropolitan area, the Tokyo metropolitan government incorporated a possible Mount Fuji eruption in its disaster preparedness plan in 2009, based on the central government’s assumptions released in 2004.

According to the metropolitan government’s assumption, if an eruption equals that of the 1707 Hoei eruption, falling ash will reach the entire Tokyo area. In addition, ash will accumulate to a depth of about 10 centimeters in parts of Hachioji and Machida cities in the western parts of Tokyo.

In addition, facilities for supplying electricity could be knocked out due to the weight of the ash, and, as a result, blackouts could occur, leading to the long-term suspension of vital lifelines. As for disposing of the possible huge volume of ash, the 2009 disaster preparedness plan only said that it will consider it in detail in the future.

“It is expected that the disposal of ash will be implemented in wide areas. But concrete discussions on the issue will be a future challenge,” said a Tokyo metropolitan government official.

The Kanagawa prefectural government also assumes that falling ash will reach the entire prefecture with a depth totaling 64 centimeters in Yamakita town in the western part of the prefecture and 16 cm in Yokohama in the eastern part.

The Kanagawa prefectural government also assumes that key transportation routes, such as Shinkansen bullet train lines and the Tomei Expressway, will be paralyzed.

In 2009, the Kanagawa prefectural government concluded a disaster preparedness agreement with Yamanashi and Shizuoka prefectures. Based on the assumption that Kanagawa Prefecture will accept many evacuees from Shizuoka Prefecture, the Kanagawa prefectural government is considering securing evacuation routes and facilities.

According to experts, if huge earthquakes change the pressures on the underground or shake places where magma has accumulated, eruptions could occur.

After the Great East Japan Earthquake, pressures on the underground of the Japanese archipelago changed. Apparently due to the influence from the temblor, another earthquake with a magnitude of 6.4 took place below Mount Fuji four days later.

According to an analysis of a group of the government-affiliated National Research Institute for Earth Science and Disaster Prevention, the magnitude 6.4 earthquake could have caused an eruption of Mount Fuji if sufficient amount of magma had accumulated.

At present, there are no abnormal phenomena being observed in Mount Fuji. Therefore, the Japan Meteorological Agency thinks that influences from the March 11, 2011, quake have subsided.

However, Mount Fuji is an active volcano. Therefore, Toshitsugu Fujii, chairman of the government’s task force on the predictions of volcano eruptions, said, “It is rare that Mount Fuji has not erupted for as long as 300 years. We should promote preparations as quickly as possible.”

(This article was written by Yasushi Okubo, Yuki Okado, Hirotaka Yamaguchi and Shigeko Segawa.)

© Copyright 2012 Asahi Shimbun and AJW  - Published at Set You Free News with license

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