Will it ever be possible to create buildings that are completely impervious to earthquakes?

In February 2010, a catastrophic 8.8-magnitude earthquake struck Chile, so powerful it shifted the planet’s axis and reduced the length of a day. The disaster resulted in over 700 fatalities in Chile [source: Than].

Despite its lower intensity, a 7.0-magnitude earthquake in Haiti just a month earlier claimed the lives of over 200,000 people. Why did this less intense quake cause more fatalities?

Buildings.

Chile enforces stricter building codes compared to Haiti and possesses the financial resources to implement them. As a result, Chile has a greater number of earthquake-resistant structures, which are less likely to collapse on their residents [source: Sutter].

There is a significant distinction between an earthquake-resistant building, designed to remain standing even when damaged, and an earthquake-proof building, engineered to withstand seismic forces without any damage. An earthquake-resistant structure is reinforced to prevent it from crumbling (allowing people to escape); an earthquake-proof building, on the other hand, incorporates features to safeguard it against lateral movement. This shifting is typical during earthquakes as seismic waves cause buildings to sway more sharply until they fail. The taller the building, the more noticeable the motion at the top floors during an earthquake. If the building sways to such an extent that it surpasses its elastic limits, it will break [sources: Reid Steel, Structural Engineers Association of Northern California].

The concept of earthquake-proof buildings mirrors the resilience of the willow tree, known for its flexibility. While strong winds may push the tree, causing it to bend, it seldom breaks. Earthquake-proof buildings follow the example set by nature.

The effectiveness of earthquake-proof buildings lies in their ability to adapt. However, this also presents a challenge. Although we can draw inspiration from nature, materials used in construction behave differently. Trees can bend, but bricks cannot.

So, what would it take to make a building earthquake-proof? From raw materials that can expand and contract, to foundations that absorb vibrations and futuristic spiderweb-like designs, there has been a surge of innovative ideas aimed at preventing buildings from collapsing during seismic events.

However, the main barrier to implementing these solutions often comes down to financial concerns.

Designing an Earthquake-proof Building

Numerous buildings located along fault lines in earthquake-prone regions were not designed to endure intense seismic activity. Although some have been reinforced with extra shells or sturdier internal frameworks, the majority have not been retrofitted, simply due to the high costs involved.

This could, however, be changing. For instance, in San Francisco, a law passed in 2013 mandates that owners of wood-frame soft-story buildings at least three stories high, built before 1978, must retrofit them. The cost to retrofit one of these buildings is estimated to range from $60,000 to $130,000. Property owners have raised concerns over the expense, as have tenant rights' groups that fear these costs will be passed on to renters in the form of higher rent [sources: Lin, City and County of San Francisco].

In the past, reinforcing buildings often involved strengthening beams, columns, and building walls with braced frames. However, newer methods focus on the foundations. Consider the world's largest earthquake-safe building, located at Istanbul’s Sabiha Gökçen Airport. The 2-million-square-foot terminal works like a giant roller skate, as it sits atop more than 300 bearings, or isolators. Instead of being tied to the earth with a traditional foundation, the terminal rolls smoothly during an earthquake. The isolators act as shock absorbers, enabling the building to sway without causing significant damage during seismic events of up to magnitude 8.0 [source: Madrigal].

To build earthquake-resistant structures, it's crucial to isolate a building’s foundation and absorb the energy generated by seismic activity as it travels beneath the building. Aside from bearings like those used at the Istanbul airport, other isolator systems exist. One system utilizes a small number of bearings that move along curved rubber pads placed between the foundation and the structure, permitting the base to shift during an earthquake while minimizing the movement of the structure itself. Other technologies concentrate on dissipating the energy caused by seismic motion, functioning as giant shock absorbers between the foundation and the building [source: MC EER].

While this technology is becoming more common, it still represents a significant expense. For instance, an architectural website estimates that retrofitting a high school would cost $781,000, and retrofitting a 2,300-square-foot (213-square-meter) house would cost $17,000 [source: Kuang]. If building owners and contractors in the United States find the costs for earthquake-proofing high, consider how this must impact developing nations.

However, there are affordable ways to implement these principles. Safer buildings can be constructed using repurposed materials, such as tires filled with stones placed between the foundation and the floor. Walls can be reinforced with natural, flexible materials like bamboo or eucalyptus. Additionally, heavy concrete roofs can be swapped for flexible sheet metal supported by wooden trusses [source: National Geographic].

Earthquake-proof Buildings in Action

While it's impossible to guarantee that any building will survive every earthquake—since the severity of the event matters—there are construction practices that significantly improve the likelihood of a building withstanding the forces. We've already discussed some of these techniques, but there are additional methods that can also help.

Due to their towering height, the tallest buildings around the world face some of the greatest risks during earthquakes. Fortunately, they also incorporate some of the most cutting-edge technologies designed to make them earthquake-resistant.

Taipei 101, a 101-story skyscraper in Taiwan, stands near a major fault line. It was built to endure not only earthquakes but also the strong typhoon winds that regularly hit the region. The answer? An enormous internal pendulum. Inside the building, a massive 730-ton (662-tonne) steel ball starts to swing when the building moves, counteracting its sway [source: Tech News].

Take, for instance, a remarkably straightforward solution being tested to protect homes from earthquake damage. Air Danshin, a company based in Japan, is exploring the benefits of a house built on top of a deflated airbag. When the sensors detect ground movement, an air compressor inflates the bag, lifting the house off its foundation in mere seconds. While this concept performed well in simulated tests and shows promise during smaller lateral earthquakes, skeptics question whether the expensive airbag would be effective in protecting a home during a large earthquake [source: Abrams].

More and more, researchers believe the future of durable buildings could come from merging natural materials with modern science. Super-strong substances found in nature, such as spider silk or mussel fibers, may serve as inspiration for the next generation of earthquake-resistant architecture.

Spider silk is incredibly strong, surpassing steel when measured by weight. Additionally, it has the ability to stretch and flex without breaking. For example, the strong, cable-like threads produced by blue mussels along the New England coastline secure the mussels to rocks even in the face of powerful ocean waves.

The remarkable combination of strength and flexibility found in spider silk and mussel fibers is exactly what engineers are seeking for more durable buildings. The rise of 3-D printing, a technique where materials are applied in layers to form three-dimensional objects, may enable the creation of construction materials that are both rigid and flexible — ideal for resisting earthquakes [sources: Chandler, Subbaraman].