2026-03-13 • 5 min read • Fundamentals

What is Seismic Isolation? The Science of Earthquake Protection

Kerim Efe Ozcanli

Independent owner's advisor, seismic isolation

Think about the biggest investment of your life. It's probably your home. Years of mortgage payments, accumulated savings, your family's future, all contained within those four walls. Now imagine this: a 30-second earthquake could reduce that investment to zero. In Turkey, this isn't hypothetical; on February 6, 2023, tens of thousands of families experienced exactly this.

Is there a solution? Yes, and it's been proven for decades: seismic isolation.

How Does Seismic Isolation Work?

Imagine driving a car without shock absorbers. Every bump, every pothole would transfer directly to your spine. Now think about riding in a luxury car, the same road, but the shocks are absorbed by the suspension system. You barely feel anything.

Seismic isolation works on the same principle. Special devices called isolator bearings are placed between the building's foundation and superstructure. During an earthquake, the ground moves violently, but the isolators absorb and dissipate this energy. The building moves slowly and gently, like a ship on calm waters while a storm rages beneath.

Key Benefits

Sharp force reduction: at Adana City Hospital the 2023 reconnaissance estimate was a roughly 75 percent cut in base shear demand
Zero structural damage in design-level earthquakes
Operational continuity, buildings remain functional after earthquakes
Content protection, reduced acceleration protects equipment and furnishings

Two Main Isolator Types

LRB (Lead Rubber Bearing): Invented in 1975 by W.H. Robinson in New Zealand and first used in a building in 1981. The yielding lead core provides damping, and the type has the longest field track record of any isolator.
FPS (Friction Pendulum System): Developed by V.A. Zayas, who founded Earthquake Protection Systems in 1985; validated in shake-table tests at UC Berkeley in 1987. Its nominal isolation period comes from the geometry of the curved surface rather than the building weight, though the effective period in a real earthquake also depends on displacement amplitude.

Each type offers different advantages. For a detailed comparison, read our LRB vs FPS comparison article.

Real-World Proof: 2023 Turkey Earthquakes

The February 6, 2023 Kahramanmaraş earthquakes (Mw 7.8 and 7.5) devastated southeastern Turkey, causing over 50,000 deaths and destroying around 38,000 buildings and leaving more than 200,000 severely damaged. Yet seismically isolated structures like Elbistan State Hospital sustained zero structural damage and remained fully operational, treating earthquake victims while conventional hospital buildings in the region were damaged or had to be evacuated.

Conclusion

Seismic isolation is proven science, validated in thousands of structures worldwide. In Turkey, hospitals that survived the 2023 earthquakes with zero damage are the most tangible proof. This technology is applicable to your home, workplace, or new construction project. If you are unsure whether your project fits, our guide on when a building needs seismic isolation walks through the decision criteria.

Next step: book a consultation for your building. See the actual seismic parameters, risk score, and isolation benefit for your building's location with concrete numbers.

Read this article in Turkish: Sismik İzolasyon Nedir | Also available in Turkish on sismikizolasyon.com

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Frequently Asked Questions

How does seismic isolation protect buildings during earthquakes?

Seismic isolation uses specialized bearing devices placed at building foundations to decouple structures from ground motion during earthquakes. These isolators absorb and dissipate earthquake energy through elastomeric and steel components, sharply reducing the forces transmitted to the building and preventing structural damage; at Adana City Hospital in 2023 the estimated reduction in base shear demand was roughly 75 percent.

What are the main types of seismic isolators?

The two primary isolator types are Lead Rubber Bearings (LRB), which use yielding lead cores for damping and have the longest field track record of any isolator, and Friction Pendulum Systems (FPS), which employ curved sliding surfaces so the isolation period is independent of building weight.

How much does seismic isolation reduce earthquake forces?

Seismic isolation sharply reduces the forces a building must resist; reconnaissance after the February 2023 earthquakes estimated a roughly 75 percent cut in base shear demand at Adana City Hospital. Real-world data from the 2023 Turkey earthquakes demonstrated that seismically isolated hospitals such as Adana City Hospital sustained no structural damage and stayed operational while conventional hospital buildings in the region were damaged or had to be evacuated.

Is seismic isolation suitable for residential buildings?

Yes, seismic isolation is used in residential buildings as well, particularly larger multi-unit projects where the premium is spread over many units. It provides superior earthquake protection, reduces interior damage and contents loss, ensures occupant safety and comfort, and many modern residential projects now incorporate seismic isolation systems.

How long do seismic isolators last?

No standard assigns a lifespan in years to either type. Isolators, elastomeric and sliding alike, are qualified for the design working life of the structure through accelerated aging and durability testing, and neither type has a code-mandated replacement schedule. Both rely on periodic inspection: a baseline check after installation, visual checks on the interval set by the project specification, and an extraordinary inspection after any significant earthquake.