When bracing for future disasters, look to the past

QUAKE-RESISTANT buildings are the buzzword again after the April 11 8.6-magnitude earthquake off northern Sumatra.

With increased stress levels along the tectonic plates on which the island rests, say experts, a potentially massive temblor could strike Padang, which is 475km from Kuala Lumpur, any time.

Over in Japan, a recent government study estimates that the chance of a magnitude-7 quake in the Tokyo area is 70 per cent over the next 30 years.

Japan experiences an average of three earthquakes daily. (In 2010, for example, according to Japan's Meteorological Agency, there were over 1,300 earthquakes ranging from the weakest to medium intensity.) Many of its buildings boast the latest in quake-resistant technology such as damping and vertical seismic isolation devices.

And experts at institutions across the nation track potential disasters on land and at sea using a network of sensors and seismic buoys. But their largest earthquake and the ensuing tsunami on March 11 last year were a reminder not to rely on technology alone and to turn to traditional wisdom as well when preparing for disasters.

Yoshimitsu Okada, president of Japan's National Research Institute for Earth Science and Disaster Prevention, wrote in a research report on the "Great East Japan Earthquake Disaster" that although a foreshock of magnitude 7.3 struck two days before, "no alarm was issued." Nor had the possibility of such a gigantic earthquake been predicted in the long-term forecast of inter-plate earthquakes off the Tohoku region.

The earthquake hit the Institute's Earthquake Data Management Centre in Tsukuba in Ibaraki prefecture. Its high-sensitivity seismograph network recorded waveform data but the processing system was damaged.

The centre's system failed a few hours after the quake due to power failure and the destruction of seismic stations near the Pacific coast by the tsunami. (It was down for a few days, but the data was later recovered.)

In Iwate prefecture, Kamaishi held a Guinness World Record for the deepest sea wall, pointed out Hatsuhisa Takashi-ma, former Ministry of Foreign Affairs press secretary and special adviser to Japan International Broadcasting Inc during a visit to Kuala Lumpur last month.

It was sixty-three metres to the seabed at the deepest point and was expected to prevent any damage to the city. But facing waves as high as 11.5m last year, the wall collapsed.

"It delayed the arrival of the tsunami and eased its strength, but could not prevent it reaching the city and taking over 1,000 lives," said Takashima. "Human effort to prevent a tsunami is not sufficient."

On the other hand, the town is also remembered for the "miracle of Kamaishi". According to Yomiuri Shimbun, "the great majority of the 3,000 primary and middle school students in the city fled to safety and were physically unhurt. Many children decided on their own that it would be risky to take shelter at designated evacuation sites, and instead made a beeline for higher ground to escape the oncoming tsunami."

This was the result of seven years of drilling on the basics of evacuation. The newspaper reported that in other places, "children heard from elderly local people who experienced massive earthquakes in the past."

The Ibaraki prefectural government delved even further back into the past. During the Edo era, says vice-governor Yachie Yamaguchi, there were reports of a tsunami in 1677. Looking at how far the flood had reached then, she says, a decision was made to raise the height of the sea wall, to ensure the safety of the Tokai nuclear plant.

It was completed just half a year before the "3/11" tsunami. "If we had not done this, we may have suffered the same consequences as the Fukushima-Daiichi power plant," she says. (When all power was lost for several hours at the plant in Fukushima prefecture, the reactors and spent fuel rods overheated, and many fuel rods melted.) "We are reflecting on the lessons learned historically, to make improvements."

As the world's most earthquake prone country, Japan has experienced numerous tsunamis and other natural disasters, says Takashima. Several years ago, scientists found residue far inland from a tsunami 1,000 years ago, he pointed out.

"People forget the experiences in the past. Although the government tells them how bad it was, sooner or later that traditional heritage will evaporate and people start living on lower ground, close to the sea."

There's a traditional saying, he remembers: "'If there is a strong earthquake, leave anything you are doing and run to higher ground.' But that lesson has not been shared totally -- and has to be relearned."

A memorial, possibly for a child, in Japan’s Miyagi prefecture a year after the tsunami flooded the Ishinomaki port area. Historians and scientists say previous tsunamis reached even further inland.

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