Protecting Cultural Properties from Disaster BOSAI Science that Can Save Your Life;

Japan's cultural properties are world-renowned treasures. These include ceramics, paintings, and architectural structures that have been carefully preserved from the past. Yet, in disaster-prone Japan, precious cultural properties have often faced crises. A famous castle collapsed in a massive earthquake. This museum flooded from torrential rain. Some 230,000 artworks and other items were damaged. And restoration efforts continue to this day. That's why Japan is expanding the use of cutting-edge disaster preparedness technology to protect its irreplaceable cultural properties. Seismic isolators shield valuable ceramics from earthquakes. Special wire is employed to protect world heritage structures. Its appearance belies advanced technology to improve strength. Today, we'll see how the latest technology is protecting Japan's cultural properties. Natural disasters not only threaten our lives and livelihoods, but also risk destroying precious cultural treasures. That's why there is now a growing effort in Japan to protect cultural properties using the latest disaster preparedness technology. Let's take a look. I visited an art museum in Tokyo. I spoke with curator Hasegawa Shoko. The museum is located within the Meiji Seimeikan, itself an important cultural property. It's a representative example of Western-style architecture in Japan. The Seikado Bunko Art Museum occupies the first floor. It holds numerous precious artworks, including national treasures and important cultural properties. Hasegawa takes us straight over to the museum's prized masterpiece. This is the best part of the teapot, the Yohen Tenmoku. Please have a look. It's like the deep sea, like the universe. It's so beautiful. This national treasure was made in China during the 12th to 13th centuries. Its beautiful blue and lapis-like patterns are thought to have emerged from accidental glaze changes in the kiln. So some call it a miracle teapot. The Yohen Tenmoku is one of only three remaining teapots. What do you think is hidden in the Yohen Tenmoku? In this teapot? That's right. The technology is hidden here. A seismic isolator to suppress earthquake shaking is installed here. How exactly does it protect the Yohen Tenmoku? Let's conduct an earthquake vibration test using the same seismic isolator. Inside the display case is a glass vase, and the seismic isolator is installed beneath the case. Now we'll simulate the shaking of a magnitude 7.3 earthquake. The floor begins to shake. The display case sways slightly, but the vase shows no sign of toppling. Let's watch that again, focusing on the seismic isolator's movement. When the ground shakes to the right, the device juts out to the right, but the display case remains almost in the same spot. Similarly, when the ground shakes to the left, the device juts out to the left, and the display case barely moves. This is why the vase didn't fall. Let's examine the key components of the device. The secret to why the Yohen Tenmoku doesn't fall lies here. The rolling bearing consists of two plates, top and bottom, with rails in between. The top plate moves horizontally 360 degrees, absorbing the seismic resonance of the seismic isolator. Here's how it works. Inside, metal balls roll along the rail, preventing earthquake vibrations from transferring to the main structure. This is called a linear bearing. The seismic isolator has rails for movement in every direction. Being arranged in two tiers allows simultaneous multi-directional movement, enabling it to handle 360-degree shaking. This seismic isolator with linear bearings is used in various buildings across Japan, such as offices, data centers, and hospitals. The Yohen Tenmoku is protected by the latest durable glass and a display case equipped with a seismic isolator. Japan's cultural properties include not only works of art, but also numerous historical structures. What kind of disaster preparedness technologies are used in such buildings? Let's find out. The Holy Spirit Hospital Chapel in Kanazawa is a prefecturally designated cultural property. This wooden church was built over 90 years ago by a Swiss architect, featuring stained glass in its arched windows and pillars finished with traditional Japanese black lacquer. It is a unique building, harmonizing Western and Japanese sensibilities. A certain item was developed to protect cultural properties such as this church from disasters. Let's see what it is. Do you see this thin wire? A thin wire? Is this it? Yes, that's right. This is a wire from the seismic insulator we developed. This wire is wound around this building as a whole. By installing this wire, it protects the building from earthquakes. In 2021, seismic reinforcement work was carried out on the church using this special wire. Two wires are strung diagonally between the ceiling and wall columns to create diagonal bracing and reinforce the structure. It's not visible, and by adding diagonal bracing to the walls and ceiling, it makes the building less prone to swaying and collapsing. That's why this wire for cultural properties was developed. It can be easily and discreetly installed in key areas. This allows seismic reinforcement without changing the building's appearance. And this wire has a special feature. Let's compare it to metal wire used on construction sites. We'll check the weight of wires of the same length. First, the metal wire. Next, the special wire. Despite being the same length, the carbon fiber wire weighs only one-fifth of the metal wire. Actually, this wire is made of carbon fiber composite material and is highly durable. Carbon fiber refers to extremely thin fibers composed primarily of carbon. It's called the ultimate material as it is lightweight, strong, and corrosion-resistant. Used in airplanes and rockets, it is indispensable in cutting-edge technology. Now, let's see just how strong the wire is. This device pulls the wire upward to determine how much force it can withstand. First, the metal wire is tested. Next is the carbon fiber. The carbon fiber wire withstood approximately 101 kilonewtons. Despite being one-fifth the weight of metal, carbon fiber boasts twice the strength. There's a secret to that strength. At first glance, carbon fiber appears to be an extremely dense material. However, viewed at the microscopic level, it contains numerous gaps. This is a micrograph. The black spots are the carbon fibers, while the white areas are resin and other materials filling the gaps. Takino and his team achieved high strength by impregnating these gaps with a specially developed resin. Wire manufacturing also employs this technique. The wire is made by twisting together seven strands of resin-filled carbon fibers. Twisting the carbon fibers creates a flexible, resilient wire. This wire is used in some of Japan's most iconic cultural properties. It protects the Tomioka Silk Mill, a UNESCO World Heritage Site, and Kyoto's national treasures, Kiyomizudera Temple and Nijo Castle, among other precious cultural properties. Cultural properties symbolize Japan's traditions and history. Once lost, they cannot be recovered. Hopefully, the advanced disaster preparedness technologies we saw today will continue to protect these cultural assets for generations to come.