Shiro Higuchi thanks his lucky stars as his son had the foresight to build a family home that literally "lifts" on its foundations when an earthquake hits.
The three-story house in Tokyo’s Ota Ward was completed one month before the magnitude-9.0 Great East Japan Earthquake struck in March 2011.
"I wasn't even aware of the quake" (which registered about 5 on the Japanese seismic scale of 7 in Tokyo), Higuchi, 74, said. "I was putting things back in their place at the entrance when it happened. I heard what sounded like air under pressure being released and I thought, ‘My son has activated the seismic isolation system again.’ But looking out of a window, I saw cars being shaken violently in the parking lot next door. I was afraid the cars might come crashing into the house."
Higuchi's house was built on a two-layered foundation.
When sensors installed at the base detect initial tremors above a certain level, air is pumped at high pressure between the layers. This lifts the structure by 2 centimeters. After tremors wane, the air is discharged and the structure settles in its original position.
Higuchi's son Kenji, 44, is a home builder. His company's office is located next to the house.
"I studied how to build quake-resistant houses, and I came across the website of a company that developed the air seismic-isolation technology three years ago," Kenji said. "I was intrigued by the company's idea that houses are not shaken if they are in the air. I liked the simplicity of the system as well."
The father and son visited the company in Ibaraki Prefecture to learn more about the technology.
"My son told me he wanted this house to be equipped with the system. So we went to the company. I was suspicious about the technology at first, but (in any event) we were safe after the huge earthquake."
Referring to that day just over a year ago, Higuchi said: "I rushed to a room on the second floor, where my wife was taking a nap. 'There was shaking,' she said drowsily. 'That was a long one, wasn't it?' I also didn’t feel a big quake had happened."
The son recalled that he watched video footage nearly two years ago of a test using a large-scale earthquake simulator at the National Research Institute for Earth Science and Disaster Prevention.
"I decided then and there to use the technology in my parents’ new home," he said. "I hear the technology was used for about 50 houses across the country before the disaster, and that 50 more with the system have been built since then."
Cost could be a problem. The two-layered foundation requires an additional outlay of between 4 million yen and 5 million yen ($48,000-$60,000).
"For a while after the earthquake, my family of five stayed in my parents' home. We were not scared by Earthquake Early Warning alarms. I have come to appreciate the importance of being free from anxiety at home."
The air quake-proof system can be used for wooden structures up to three stories.
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