damage, disaster area, disaster prevention/mitigation, natural disaster hazards, yomiuri shinbun

REVITALIZING JAPAN — Building a disaster-resistant nation / How should we be prepared for ‘calamity’ in 1,000 yrs?, yomiuri, 1/18/12

This is the first installment in a series of articles examining ways to restore Japan’s vitality.

Shortly after the Great East Japan Earthquake, the director of the Disaster Control Research Center of Tohoku University visited Minami-Sanriku Town in the northeastern part of Miyagi Prefecture on the Pacific coast.

What Fumihiko Imamura saw there in the middle of March was appalling: havoc, the extent of which was far beyond anything he had ever imagined as a disaster control expert.

The gigantic tsunami had crossed over the seawall of the Shizugawa district in the southern area of Minami-Sanriku, and subsequently destroyed a sturdy iron railing before ruining the entire embankment.

A catastrophe of that scale could take place once in several hundred to 1,000 years, he said.

“Since we had engaged in a wide range of disaster management efforts in this region, I cannot help but feel extremely deep regret,” Imamura said.

He noted, “We must think seriously of how to face the risk of an ‘extremely low- probability calamity,’ and how to hand down lessons learned for posterity.”

The massive magnitude-9 March 11 temblor, the largest in the nation’s history of scientific earthquake observation, is reminiscent of an earthquake an ancient document says struck in 869 during the Jogan era and caused a great deal of damage in the Tohoku region.

According to Akira Sangawa, a guest researcher specializing in seismological archaeology at the government-funded National Institute of Advanced Industrial Science and Technology, right around the 9th century, when the Jogan earthquake occurred, Japan was in a period of frequently occurring earthquakes.

“Judging from [the trend in] recent years, this country may again be in a phase of active seismological events,” Sangawa said.

This view is shared by many other experts who believe that Japan, after the 1995 Great Hanshin Earthquake, entered an active period of seismological activity, and that there is a significantly high possibility of another massive earthquake occurring before the end of the 21st century.

The edges of four tectonic plates meet beneath the Japanese archipelago, and the incidence of volcanic eruptions increases depending on the plates’ activities.

There were a series of eruptions at Mt. Shinmoedake in southern Kyushu at the beginning of 2011, while the number of major eruptions, called explosive eruptions, at Mt. Sakurajima in Kagoshima Prefecture, registered a record high, surpassing 900 compared to the previous high of 896 in 2010.

In this “archipelago of frequently occurring natural disasters,” abnormalities such as unpredictable, sudden downpours called “guerrilla cataracts,” huge typhoons and intense heat waves have become conspicuous in recent years.

Experts have been alarmed by these phenomena, calling them “meteorological aberrations.”

Japan witnessed such irregularities last summer. Typhoon No. 12 registered the largest rainfall on record, and Typhoon No. 15 saw evacuation recommendations issued to as many as 1.22 million people in Aichi Prefecture and elsewhere.

According to statistics from the Meteorological Agency, heavy rain in Japan has been on the rise over the past 100 years or so. Although the cause behind the increased rainfall remains unknown, some scientists believe it may be linked to global human activities.

As Masahide Kimoto, vice director of the University of Tokyo’s Atmosphere and Ocean Research Institute, puts it: “As the earth’s climate changes, antidisaster preparations should be thoroughly reviewed, starting with city planning. Conventional wisdom can no longer cope with the situation.”

One example of abnormalities overseas is the flooding in Thailand last summer.

Large delta regions, known as mega-deltas, are concentrated in India, Thailand and southern China. These deltas have long acted as flood cushions and sluiceways. However, due to development projects since the middle of the 20th century, these deltas have shrunk in size, which may have strongly contributed to the huge scale and prolonged nature of the floods.

Huge-scale disasters that cannot be explained by global warming alone have been on the rise worldwide.

The recent period of high economic growth, which enabled Japan’s “miraculous” economic recovery and development, happened to occur during a phase of few large-scale natural disasters in the archipelago’s history, according to some experts.

The fact that many industries and groups of people could gather in places such as Tokyo and the Tokai region, which are vulnerable to natural disasters, may have been thanks to such good luck.

With the unprecedented Great East Japan Earthquake and accident at the Fukushima No. 1 nuclear power plant, the question now is how to prepare for and prevent damage from disasters.

How much should we prepare for extremely rare disasters said to occur once every 1,000 years? And what about recent extreme weather conditions in which conventional wisdom cannot work?

During the Great East Japan Earthquake, the height of coastal seawalls affected the fates of those hit by the tsunami.

The tsunami overran an about 10 meter-high seawall in the Taro district of Miyako, Iwate Prefecture. However, a seawall measuring more than 15 meters high in the village of Fudai and another 12 meter-high seawall in the town of Hirono stopped the waves.

The seawall in the Taro district, which was completed in 1978, cost more than 400 million yen in total. The Fudai seawall, completed in 1984, cost 3.5 billion yen. The cost of a bay mouth seawall in Kamaishi Port, which was destroyed by the tsunami, cost 120 billion yen.

It is true that the higher the seawalls, the better. But a tsunami more than 15 meters high could hit in certain areas.

Considering costs, it is impossible to make seawalls high enough to block every possible tsunami.

Former Fukuoka Gov. Wataru Aso, who served as president of the National Governors’ Association, said: “It’s impossible to take disaster management measures by assuming [it will be] the one that takes place once every 1,000 years.

“The cost is unimaginable. I think ‘software,’ such as evacuation drills, are more important than ‘hardware.'”

In fact, experts said municipalities that practiced such drills and other “software” measures suffered less damage from the March 11 disaster.

In the case of extreme weather conditions, experts have said preventative measures have limits.

Recently, a Land, Infrastructure, Transport and Tourism Ministry council discussed transitioning away from conventional thinking that aims to prevent flooding in all rivers. The council also said it would be difficult to prevent all damage in the event of future, harsher disasters.

Experts are paying more attention to this extremely rare type of disaster.

For instance, once every 10,000 years or so, large volcanoes may have “catastrophic eruptions,” the likes of which have not been witnessed by civilizations for thousands of years.

Should this type of disaster occur, it could ruin not only a nation, but the entire planet. Experts at the Volcanological Society of Japan have begun holding symposiums with government officials to assess such risks.

A magnitude-5.8 earthquake in the eastern United States, the first since the late 19th century, occurred in August. The quake caused a nuclear power plant in Virginia to automatically stop, leading to demands from U.S. experts for measures against extremely rare earthquakes.

To prevent unusual disasters in delta areas, such as the Thai floods, U.S. environmental experts proposed holding an international conference on the issue and making 2013 an “international delta area year.”

Economic losses from the Great East Japan Earthquake are estimated at 16.9 trillion yen, excluding those from the Fukushima nuclear accident. Experts assume that it will cost 2.2 trillion yen to rebuild infrastructure alone.

Investing in disaster management–even if the measures are not perfect–can minimize losses from future disasters. Some experts believe this is fiscally desirable as Japan is involved in all types of natural disasters.

Katsuhiko Ishibashi, professor emeritus of Kobe University, who pointed out the risk of a Tokai earthquake 35 years ago, said: “We should not design our society for economic efficiency. We need to recognize Japan’s natural conditions and build suitable communities [based on that]. Because Japan is prone to natural disasters, there are lessons it can send out to the rest of the world.”
(Jan. 18, 2012)


About liz

from the u.s., recently moved from kobe to sendai, japan, researching community-based housing recovery after disaster.


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