A Century of Architectural Resilience: Japan's Journey in Earthquake-proofing
Japan's commitment to earthquake-proofing its architecture spans over a century, blending ancient wisdom, modern innovation, and evolving regulations Architects, engineers, and urban planners continuously learn from past tragedies, ensuring innovative and well-prepared buildings
Design for Impact is a series that highlights architectural solutions for communities impacted by the climate crisis, natural disasters, and humanitarian emergencies. The widespread destruction caused by a 7.5 magnitude earthquake in Ishikawa prefecture on Japan's western coast was broadcasted globally this week, showing buildings reduced to rubble.
The true extent of the damage is not yet known. While authorities have confirmed the destruction of at least 270 homes in the region, the final number is expected to be much higher. This count does not include areas such as Suzu or Wajima, a city of over 27,000 residents just 20 miles (32 kilometers) from the epicenter, where approximately 200 buildings were reported to have burned down by fire department officials, as stated by public broadcaster NHK.
These accounts highlight the personal tragedies experienced by many of the region's inhabitants. While every seismic event is unique, earthquakes of similar magnitude in other regions, such as the 7.6 magnitude quake that led to the collapse of over 30,000 buildings in Kashmir in 2005, have often resulted in significantly greater devastation.
Ishikawa, on the other hand, may have experienced less damage, as suggested by Robert Geller, a retired seismology professor at the University of Tokyo. "Modern buildings performed quite well," he informed CNN the day after the earthquake in Japan, pointing out that older homes with "heavy clay tile roofs" appeared to have suffered the most.
"According to him, the majority of single-family homes, even when damaged, did not fully collapse. The adage of seismic design emphasizes that earthquakes do not kill people, but rather buildings do. In one of the most earthquake-prone countries in the world, architects, engineers, and urban planners have been working to make towns and cities more resilient to major tremors by combining ancient knowledge, modern advancements, and continuously updating building codes."
A building in Osaka, Japan that has been strengthened to protect it from earthquakes.
Trevor Mogg/Alamy Stock Photo
Technology has advanced significantly since the Great Kanto earthquake over 100 years ago. This includes innovative "dampers" and systems of springs or ball bearings in skyscrapers that allow buildings to sway independently of their foundations, ensuring better stability and safety.
Innovations often focus on a fundamental and well-established concept: that structural flexibility increases the likelihood of survival. "Many buildings, particularly hospitals and critical structures, are equipped with rubber bearings to allow for swaying," explained Miho Mazereeuw, an associate professor at MIT who delves into Japan's culture of preparedness in her upcoming book "Design Before Disaster."
"The concept is to allow buildings to move with the Earth's movement rather than resist it. This principle has been utilized in Japan for centuries, with traditional wooden pagodas such as the 180-foot tall Toji temple surviving earthquakes that modern structures did not withstand. For example, the 17th-century pagoda near Kyoto emerged intact from the 1995 Great Hanshin earthquake, while nearby buildings collapsed."
The five-story 17th-century pagoda at Kyoto's Toji temple.
Japan's traditional architecture shares many similarities with that of neighboring Korea and China, but also incorporates unique elements that are tailored to the country's frequent seismic activity.
The impressive survival rate of pagodas has been attributed to the use of "shinbashira" central pillars, which have been utilized by Japanese architects for over 1,400 years. These pillars, whether anchored to the ground, resting on a beam, or suspended from above, have the ability to bend and flex, allowing the individual floors of the building to move in the opposite direction to their neighbors. This shimmying movement, often likened to that of a slithering snake, helps to counter the force of tremors, and is further supported by interlocking joints, loose brackets, and wide roof eaves.
Learning from tragedy
Buildings in todays Japan may not all resemble pagodas, but skyscrapers certainly do.
Japan's strict height limit of 31 meters (102 feet) due to natural disasters was lifted in the 1960s, allowing architects to build upwards. Today, Japan ranks fifth in the world with over 270 buildings higher than 150 meters (492 feet), according to the Council on Tall Buildings and Urban Habitat. High-rise designers have used steel skeletons and advancements like large-scale counterweights and "base isolation" systems to increase flexibility and minimize the dangers posed by natural disasters.
The company responsible for Japan's latest tallest building, which was unveiled as part of the Azabudai Hills project in Tokyo in July, asserts that its earthquake-resistant design features, including extensive dampers, will enable businesses to keep running even in the event of a seismic event as powerful as the historic 9.1 magnitude Tohoku earthquake that hit in 2011.
The largest tower at Tokyo's Azabudai Hills development is now Japan's tallest skyscraper.
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In places like Wajima, Japan, where skyscrapers are not common, the focus on quake resistance has been on protecting everyday buildings such as homes, schools, libraries, and stores. Japan's success in this area has been attributed to a combination of policy and technology. Japan's architecture schools have prioritized teaching students about both design and engineering, likely due to the country's history of natural disasters, according to Mazereeuw, who heads MIT's Urban Risk Lab, a research organization that studies seismic and climatic risks in cities.
"Japanese architecture schools integrate architecture with structural engineering, unlike most countries. In the US, structural engineering classes are not as comprehensive," she said, highlighting that in Japan, the two disciplines "are always interconnected."
Controversial Tokyo redevelopment plan sparks protests over building skyscrapers in Central Park.
Japanese officials have consistently sought to learn from each major earthquake the country has experienced, conducting thorough surveys and updating building regulations as a result. This process dates back to the 19th century, with the destruction of new European-style brick and stone buildings in the 1891 Mino-Owari earthquake and 1923 Great Kanto quake leading to new laws on city planning and urban buildings, as explained by Mazereeuw.
Tokyo was left in ruins following the Great Kanto earthquake of 1923.
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The gradual development of building regulations persisted throughout the 20th century. However, a significant turning point occurred with the introduction of the "shin-taishin," or the New Earthquake Resistant Building Standard Amendment in 1981. This code was a direct response to the offshore Miyagi earthquake three years earlier, marking a crucial moment in building safety standards.
By implementing higher requirements for new buildings' load-carrying capacity and "story drift," the new standards have proven highly effective. Homes built to pre-1981 standards, also known as "kyu-taishin" or "before earthquake resistance," are now significantly more challenging to sell and insure at a higher cost. The regulations faced their first real test in 1995 during the Great Hanshin earthquake, which caused widespread destruction in the southern part of Hyogo prefecture. According to the Global Facility for Disaster Reduction and Recovery, 97% of the collapsed buildings were constructed before 1981, highlighting the stark impact of the new regulations.
Innovation and preparation
The earthquake in 1995 prompted a countrywide effort to upgrade older buildings to meet the standards set in 1981, a process that has been encouraged by city officials through various subsidies. Over the years, there has been ongoing innovation in seismic design, with Japanese architects frequently at the forefront of these developments.
A seismic isolation system on a column-head at the engineering firm Shimizu Corporation's research facility in Tokyo, Japan.
In 2016, renowned architect Kengo Kuma partnered with textile company Komatsu Matere to create a curtain made of thousands of braided carbon fiber rods for the company's headquarters, located just 85 miles from the epicenter of a recent earthquake. The curtain acts as a tent-like support system, anchoring the building to the ground. Kuma also collaborated on a kindergarten building in southern Kochi prefecture, incorporating a quake-resistant checkerboard-style wall system. (Image at top courtesy of Kimimasa Mayama/Bloomberg/Getty Images)
Elsewhere, prominent Japanese architects such as Shigeru Ban and Toyo Ito have been at the forefront of utilizing cross-laminated timber (CLT), a new form of engineered wood that its proponents believe has the potential to revolutionize the construction of high-rises. (The inaugural full-scale earthquake simulator test of an engineered timber tower occurred at the University of California San Diego last spring. However, whether the proposed 1,148-foot-tall CLT tower in Tokyo, put forward by Japanese company Sumitomo Forestry, can comply with Japan’s stringent building codes is a separate issue).
An anti-seismic pillar used in the design of an old wooden house in Miyama, Kyoto prefecture.
Eric Lafforgue/Art in All of Us/Corbis/Getty Images
Modern technology enables designers to simulate earthquake conditions and construct buildings accordingly. However, the resilience of most disaster-proofed structures has fortunately not yet been challenged.
Speaking on the topic, Geller from the University of Tokyo mentioned, "There is a significant number of high-rise buildings that have been meticulously designed for safety, primarily relying on computer simulations. The accuracy of these simulations remains uncertain until a major earthquake occurs. The collapse of even one high-rise building could result in extensive damage."
Billions of birds collide with glass buildings, but there are solutions in architecture. Consequently, the lingering question for Japan's engineers and seismologists is: What if a major earthquake were to directly strike a city like Tokyo, as officials in the Japanese capital have warned there is a 70% chance of in the next 30 years?
"Tokyo is probably reasonably safe," he added. "But theres no way to know for sure until the next big earthquake actually happens."
CNNs Eric Cheung and Saki Toi contributed to this report.
