Definition
Earthquake-resistant design is an engineering technique that shapes a building's frame and structure so it doesn't easily collapse when the ground shakes hard. The building either stands firm against the huge shock energy coming up through the ground or spreads it out gently, protecting the lives and safety of the people inside.
What happens to a building when the ground shakes?
When a subway car suddenly stops, your body lurches forward. In the same way, when an earthquake jolts the ground from side to side, a building feels a powerful force of inertia (the tendency of things to stay as they were). The ground snaps to the left, but the upper part of the building wants to stay where it was. So enormous twisting and tearing forces pile up in the columns and walls at the bottom.
If a building is merely stiff, it can't take that huge force. It can shatter in an instant and fall, like a glass cup. To survive an earthquake, a building needs strength, but it also needs ductility, the ability to stretch, so it bends flexibly under force instead of snapping.
When a building's columns and beams (the horizontal supports running between columns) are woven tightly with tough steel rebar and wrapped firmly in concrete, the columns don't buckle under violent shaking. They hold up against the earthquake's energy, and the building stays standing.
More precisely: seismic resistance, vibration control, and base isolation
What we casually call "earthquake-resistant design" actually splits into three distinct approaches, depending on how engineers handle the force. The first is "seismic resistance" in the narrow sense. Columns and shear walls (walls that carry the building's weight) are made very thick and strong, so the building takes the quake's impact head-on and holds firm.
The second is "vibration control." Huge dampers (special shock absorbers) or a heavy weight are installed inside the building or on the roof. When the quake tips the building to the right, the weight swings to the left and pushes back. It absorbs the vibration energy passing into the building and greatly reduces how far it sways.
The third and most advanced is "base isolation." Highly elastic rubber bearings or sliding bearings are placed between the building's base and the ground. This creates a cushioning layer between the two. Even when the ground shakes violently, the building feels only a much weaker, slow sway.
Not collapsing is the best shield
Many people assume a building with earthquake-resistant design should come through a quake perfectly fine, without so much as a hairline crack in the wall. But in earthquake engineering, the most basic goal is not to preserve how the building looks. It is to protect the lifeline that lets the people inside get out safely.
When a record-breaking giant quake hits, even an excellent earthquake-resistant building may get big cracks in its walls or have some columns crushed. This isn't poor construction. It is the building's normal defense at work: it deforms and breaks in places, and in doing so it absorbs and uses up the destructive energy that came up from the ground.
As long as the building keeps its frame and doesn't come crashing down, the people inside can calmly walk down the stairs once the shaking dies down. Even if the building has to be repaired or rebuilt afterward, keeping safe the lives that can't be replaced is the real reason earthquake-resistant design exists.
Common misconceptions
A building with earthquake-resistant design should come through a quake without a single crack in its walls.
The first goal of earthquake-resistant design is not keeping the building looking intact. It is saving lives by preventing collapse. A building absorbs the shock energy by crumpling or cracking itself, so some damage can happen.
Where you meet it
Near the top of Taipei 101 in Taiwan hangs a giant yellow steel weight of 660 tons, which cancels out the swaying from earthquakes and typhoons.
Some hospitals and data centers in Japan put thick laminated rubber bearings under the building's foundation, so less vibration travels up into the building during a quake.
In one sentence
Earthquake-resistant design keeps buildings from collapsing and saves lives by withstanding quake energy (seismic resistance), absorbing it (vibration control), or blocking it (base isolation).