Engineering
The Hidden Math Behind Earthquake-Proof Skyscraper Foundations
Quick fact
A 30-story skyscraper typically has a natural frequency around 0.2 Hz (a period of 5 seconds), while a typical earthquake's shaking is strongest at about 1 Hz (1 second). This mismatch means tall buildings are often safer in distant quakes, but adding mass or changing stiffness can shift them into a dangerous resonance zone.
Why this is interesting
Why do skyscrapers sometimes sway gently during a distant earthquake, while a small house might shake violently? The secret lies not in size, but in a hidden mathematical relationship called resonance.