Can my home withstand a large aftershock… Automatic judgment, practical application September 1 20:18

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After the building was struck by an earthquake, the development of a system that automatically determines whether it can withstand a large aftershock is at the final stage of commercialization. If you know whether your home is safe immediately after the disaster, it is expected to help ease congestion in evacuation centers and speed up life reconstruction.

Professor Koichi Tsuji's group at the Earthquake Research Institute at the University of Tokyo is conducting research on a mechanism for judging the safety of buildings immediately after the earthquake. Currently, the system has been installed in about 40 buildings in the Tokyo metropolitan area, etc. Development is in progress.

This system measures the acceleration of shaking with a sensor attached to the building, calculates the magnitude of the applied force and deformation, and judges safety.

The point is to predict not only the damage caused by the first shake but also whether it can withstand aftershocks, and it is possible to judge the damage when attacked by the same degree of shake from “none” to “collapse” in 6 stages That is.

At present, the safety of damaged buildings is evaluated by “Emergency Risk Assessment”, in which each building is visually checked, but it is only about 1 to complete the survey in the Kumamoto Earthquake three years ago. It took me half a month.

Because the new system automatically knows the safety of your home immediately after the earthquake, it is expected to help reduce congestion at evacuation shelters and speed up life reconstruction.

Prof. Tsuji said, “You can decide whether you want to go to a refuge or stay at home, and the side that accepts the victims can quickly determine whether you can use a school or a gymnasium. I think there are benefits. "

This system is compatible with wooden houses as well as buildings and condominiums and can be installed later, but it costs about several hundred thousand yen for wooden houses and about one million yen for high-rise buildings. The research group aims to reduce costs and put it to practical use.

A person with a sensor

Mr. Keisuke Iwasaki, 36, a company employee in Yokohama, learned that a new system was being developed, and in June he asked the research team to install a sensor when he built a new home. . When I lived with my wife and two children, I wanted to immediately check if my home was safe in the event of a major earthquake.

In June, there was an earthquake observing a tremor with a seismic intensity of 3, but it was said that there was no damage, and that it was safe. Mr. Iwasaki says, “It ’s a big difference between being judged as“ no problem ”and thinking“ maybe it ’s OK. ”Amateurs do n’t know if it ’s dangerous or safe. I can immediately decide whether I should continue living or evacuate, and I think it is worth it. "

Visual judgment that takes a long time

There is “Emergency Risk Assessment” as a system to judge the risk of buildings damaged by an earthquake. As a rule, qualified architects visually check whether the walls and foundations of the building are broken or cracked from outside the building, and whether the pillars are tilted.

Judgment results are shown in three stages: red “danger” if entry is dangerous, yellow “caution” if sufficient attention is required, and green “examined” if available.

According to the Japan Architectural Disaster Prevention Association, the “Emergency Risk Assessment” was first conducted on a large scale in the 1995 Great Hanshin-Awaji Earthquake, and at this time, a total of 6500 judges judged over 46,000 buildings for 3 weeks In addition to the survey, 3800 years ago, a total of 6,800 people surveyed over 57,000 buildings, and it took about a month and a half to finish all of them.

It is expected that more buildings will be damaged if an earthquake directly under the Tokyo Metropolitan Earthquake occurs, and the survey is expected to take a considerable number of days.

Expected to control congestion at evacuation centers

If the group can objectively determine whether they can spend their time at home immediately after the disaster, we hope that it will help to reduce congestion at the shelter.

According to the national assumption, one day after the earthquake directly below the capital, approximately 3 million evacuees centered in the southern Kanto area, of which 1.8 million are living in the shelters. The number of evacuees is expected to increase further, up to approximately 7.2 million people, and 2.9 million people living in the shelters.

According to the Cabinet Office etc., the Hanshin-Awaji Great Earthquake has a maximum of 310,000 people, and the Great East Japan Earthquake has a maximum of about 470,000 people, and the Great East Japan Earthquake far exceeded this. The country says that "There are some shelters that cannot accommodate evacuees."

In Mashiki-cho, Kumamoto Prefecture, where two earthquakes with seismic intensity 7 were observed twice during the April 2016 Kumamoto earthquake, more than twice as many evacuees visited the evacuation center.

In addition to those who were unable to live in their homes, those who felt anxiety during the aftershock seemed to have headed to the evacuation center. .

In the event of a Tokyo metropolitan earthquake, Tokyo and others have called for evacuation at home in situations where the home can be used continuously, and the research group has objective data to determine whether to stay at home with the new system. It is supposed to be obtained.