TOKYO -
Experts say there is a high probability
that a big earthquake will shake Tokyo in the next four years but is Japan's
capital ready for such a disaster?
When
the magnitude-9 undersea Great East Japan earthquake occurred on March 11 last
year, professor Hirata Naoshi was on the 16th floor of a building in Tokyo's
government district, Kasumigaseki, attending a meeting with bureaucrats. The
agenda: earthquakes.
"Everyone
attending the meeting received an early warning system. We watched the
television news by cellphone and saw the tsunami attacking to the shore. There
were estimates of the damage but in reality, it was so much more. This was
absolutely beyond our imagination," Hirata told AsiaNews in an interview
in his office at the University of Tokyo.
Hirata
is the director of the Earthquake Prediction Research Centre (EPRC) under the
university's Earthquake Research Institute (ERI).
Like
Hirata, the rest of Japan did not expect the devastating impact that the March
11 earthquake and tsunami wrought on lives and property because tremors are a
regular part of their lives.
When a
magnitude-6.1 earthquake hit Tokyo on March 14-just three days after the first
anniversary of last year's disaster-Tokyoites just shrugged it off. At the
national stadium near downtown Tokyo, Japan's football team was just about to
win its match against Bahrain for the Asian qualifiers to the London Olympics.
The tremor was hardly felt and neither did it dampen the festive atmosphere as
evident on the live telecast.
This
seeming indifference belies the underlying fact that the Tokyo Metropolitan
Area (TMA) is vulnerable to earthquakes and a strong one may shake the core of
the Japanese capital. In January, the ERI released the results of a five-year
research study pointing to a 70-per-cent probability that a big earthquake with
magnitude-7 or higher will hit the metropolis within four years.
The TMA
is located close to the triple junction of the Pacific, Philippine Sea, and
continental plates. According to a paper by Kazuki Koketsu and Hiroe Miyake of
the ERI published in 2006, various earthquakes occur in this complex plate
system.
The
study that Hirata and his team did was to observe small- and mid-sized
earthquakes in the Kanto region. He said that after the March 11 earthquake,
there was a large number of aftershocks off the Pacific coast of northeastern
Japan as well as in inland areas.
Despite
its name, however, the EPRC does not predict earthquakes-as Hirata explained-
because there is still no available technology that can help them do so.
Instead, seismologists like him study seismic activities and warn about the
likelihood of an earthquake based on the frequency of earthquakes occurring.
"Our
understanding of the situation in Tokyo, including the Tokyo metropolitan area,
is that we had five magnitude-7 very large earthquakes in the past 100 years.
It means that in the next 100 years, we will approximately have five
earthquakes with magnitude-7.
"We
calculated the occurrence of a magnitude-7 earthquake using the relationship
between the frequency and size distribution. As of last August, the probability
is 70 per cent in four years. The number depends on many assumptions... but the
important thing is, the seismic activity is higher than before. I believe that
a magnitude-7 earthquake has a much higher probability of happening compared to
before March 11," Hirata said.
He
cited estimates by the Cabinet office that should such an earthquake hit the
Tokyo metropolis, at least 11,000 people may die and losses may amount to 112
trillion yen or about US$1.34 trillion.
"This
is more than the average Japanese annual budget," Hirata said. "So
it's very serious for people living in Tokyo to understand what kind of
earthquake we will have and hopefully, it's very useful if we can understand
when such a very large earthquake will occur."
But
Hirata fell short in specifying which part of the Tokyo metropolis, including
nearby Chiba and Ibaraki prefectures, will be most vulnerable in case a
magnitude-7 earthquake happens. He did say, however, that small wooden houses
especially those located in dense areas are more vulnerable than tall and
modern buildings.
Disaster
preparedness Japan is perhaps the most prepared country in the world when it
comes to earthquakes as the archipelago sits on an area where several
continental and oceanic plates meet, causing frequent earthquakes. Because of
this, the government has instituted a massive public education programme and
regularly revises the building code every time a big disaster happens.
According
to Shunsuke Otani of the Chiba University in a 2007 paper, the earliest law
documented relating to construction in Japan was the 1919 Urban Building Law,
which regulated building construction in six major cities. Its enforcement
regulations enacted in 1920 limited the height of buildings to 100 feet but there
were no seismic requirements that time. After the 1923 Kanto earthquake, the
government revised the law and introduced seismic design.
Between
1949 and 1950, the government introduced the Building Standard Law, which set
minimum standards for building structures; the Architect Law, which defined the
qualification of engineers who can design buildings and supervise construction
work; and the Construction Trade Law, which imposed standards on the
construction industry.
When
the Tokachi-oki earthquake occurred in 1968, the government revised the
Building Standard Law, and included seismic design codes, imposed a
vulnerability assessment on existing construction and required the retrofitting
of structures deemed vulnerable to earthquakes.
In
1995, the Kobe earthquake happened and three years later, the government
approved revisions to the Building Standard Law that included fire-resistance
and fire-prevention requirements, among others. The latest revision was in
1981.
"We
have a long history of earthquakes. After every large earthquake, we improve
the building design code. And the important year is 1981. After 1981, the
building code has been improved strong enough for very large earthquakes, even
for a magnitude-7," Hirata said.
Tokyo's
urban jungle is dotted by many skyscrapers including the Mori Tower (238
metres) in Roppongi, the NTT DoCoMo Yoyogi Building (240 metres) and the Tokyo
Metropolitan Building (243 metres). In May, the Tokyo Sky Tree, which will be
the tallest in the world at 634 metres, will open boasting a modern
earthquake-proof structure.
"A
new well-designed building will be safe, I believe," Hirata said.
"But unfortunately, we have many, many old wooden houses in the Tokyo
metropolitan area. These buildings were built when the designing code's
standards were not strong enough. It means the construction was legal at that
time they were built but they are no longer good for the current designing
code.
"And
also, the old wooden houses are not safe for fire. In Japan, when we have a
very large earthquake, we have to watch out for fire. This is very important
because about three-fourths of the deaths in the 1923 Kanto earthquake were due
to fire; and most of the houses that were totally burned were destroyed by
fire. In the greater metropolitan Tokyo area, we should be careful of
fire," he said.
Hirata
further explained that the cause of devastation from each earthquake differs:
in last year's disaster, many died from the tsunami; in the 1995 Kobe
earthquake, many were injured or killed by the collapse of wooden houses.
"Are
the buildings strong enough for the next large earthquake?" he asked.
"The answer is no. Absolutely not, because we still have a lot of very
weak houses and buildings in the Tokyo area.
"At
the centre of the business district, those tall buildings are probably strong
for shaking... but the other problem is if we have very strong ground motion,
the electric power will be shut down. The lifts will be stopped due to safety
reasons. But even if this is correctly operated, the lift system will be
stopped for a week. The pumping system for such buildings will also be stopped
and so probably there will be no water."
City
residents AsiaNews talked to noted that neighbourhoods like Asakusa, Ueno and
along the Sumida river are specifically vulnerable because of old buildings and
wooden houses. In addition, most streets in Tokyo are between 2 metres and 3
metres wide so once the buildings collapse, it may be difficult for firetrucks,
for example, to pass through. In addition, most of the residents of the old
wooden houses are elderly and may be relying on pension, thus, they have no
financial capability to have their homes rebuilt or retrofitted.
It is
not cheap to have an old structure retrofitted. A resident, who requested
anonymity, said it costs at least 2 million yen (US$24,000) to retrofit an old
house and make it earthquake-proof. The government offers a subsidy of only up
to 50,000 yen ($600).
In the
aftermath of the March 11 disaster, the government has been reviewing and
mapping out a new disaster prevention plan but Hirata said that "in
reality, this is not enough".
"We
have a lot of documentation, lots of planning but people still live in old
wooden structures, not engineered houses or built to be fire-proof. People
should start to prepare. Even in the well-constructed tall buildings, people
may not be prepared on how to survive such a very large earthquake. We have a
lot of ideas on how to survive... but we should start doing steps by ourselves,"
Hirata said.
Most
Japanese homes have an emergency earthquake kit on standby. This contains
flashlight, masks, bandages, water, food like noodles, high-energy sweets and
canned goods; rope, sanitary products and even a portable toilet, among others.
The
Japanese, as Hirata noted, have lived with earthquakes for more than 1,000
years. "We had several large earthquakes in Japan but the Japanese people
have survived so no need to escape from Tokyo," he said.
"But
maybe it's a good idea to distribute the population or some social functions
because Tokyo is the only centre for Japan for economy, politics and culture.
This is not a good idea. Everything is in Tokyo. Maybe some should be in
Sapporo, Osaka, Fukuoka."
In an
earlier interview, Tatsuo Hirano, minister in charge of the recovery from the
March 11 earthquake and tsunami, said he was confident Tokyo could withstand a
powerful earthquake as shown by the lack of serious damage to its buildings and
transport infrastructure from last year's disaster.
Yasmin
Lee Arpon
Asia
News Network
Business & Investment Opportunities
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