By Antoni Slodkowski
TOKYO, April 1 (Reuters) – Japan’s defences against a major
tsunami and the safety of its nuclear plants were thrown into
further doubt after two official studies predicted much higher
waves could hit and that Tokyo quake damage could be bigger than
it was prepared for.
The reports, carried in the media over the weekend, are
likely to intensify the debate about whether to restart Japan’s
54 nuclear reactors, all but one of which are shut amid public
fears about nuclear safety sparked by the Fukushima disaster in
March 2011.
One report said a quake as big as the one that rocked Japan
in 2011 could trigger waves topping 34 metres (112 feet), almost
double its previous estimate made in 2003 when its worst
scenario forecast tsunami of no more than 20 metres (66 feet).
The Cabinet Office panel which authored the report, revised
its predictions after one of the biggest tremors on record
struck Japan last year, setting off a tsunami that topped 20
metres in the worst-affected areas and triggering the world’s
worst nuclear crisis in 25 years.
“We won’t be able to contain a massive tsunami with the
(current) embankments,” said Masaharu Nakagawa, disaster
prevention minister on a news conference on Saturday evening.
“We will have to work the (changes regarding) the city
planning, disaster prevention education and evacuation into the
policies,” he said.
Waves at the now off-line Hamaoka nuclear plant in Shizuoka
prefecture, operated by Chubu Electric Power, could
reach 21 metres, breaching the 18-metre breakwater that the
operators are currently building, the report said.
The government is keen to get some of the reactors running
after surging fuels imports resulted in a rare trade deficit,
raising worries about its declining ability to fund a huge
public debt with domestic savings. But it must first persuade
wary locals that the plants are safe.
TOKYO IMPACT WORSE THAN FEARED
Another official report suggested that the direct impact of
a major quake has been underestimated.
It said that if a 7.3 magnitude quake hit Tokyo, some parts
of the city and surrounding areas would likely be shaken at
level 7 on Japan’s seven-point “Shindo” scale of seismic
activity, it said.
The Shindo scale measures ground motion at a specific place
and points to the likely impact on people and structures and the
study concluded that the tectonic plates seen as the focal point
in a quake were 10 kms (6.2 miles) shallower than previously
estimated, making any impact more severe.
The government has put the chances of a magnitude 7.3 quake
centred in the north of Tokyo Bay at 70 percent over the next
three decades, and has estimated there would be about 11,000
casualties and 850,000 buildings destroyed.
Japan, situated on the “Ring of Fire” arc of volcanoes and
oceanic trenches that partly encircles the Pacific Basin,
accounts for about 20 percent of the world’s earthquakes of
magnitude 6 or greater.
A magnitude 7.3 quake hit central Japan in 1995, devastating
the port city of Kobe. It killed more than 6,400 people and
caused an estimated $100 billion in damage.
