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 Asia News in an interview in his office at the University of Tokyo.

Hirata is the director of the Earthquake Prediction Research Center under the university’s Earthquake Research Institute.

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 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-percent 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 $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.

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 program 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 quaprevision 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 meters) in Roppongi, the NTT DoCoMo Yoyogi Building (240 meters) and the Tokyo Metropolitan Building (243 meters). In May, the Tokyo Sky Tree, which will be the tallest in the world at 634 meters, 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 center 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 Asia News talked to noted that neighborhoods 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 meters and 3 meters wide so once the buildings collapse, it may be difficult for fire trucks, 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 ($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.

“Please rest assured and don’t flee Tokyo,” Hirano had said.

By Yasmin Lee Arpon

(Asia News Network)