Why do buildings fall in earthquakes? - Vicki V. May

Earthquakes have always been a terrifying phenomenon, and they’ve become more deadly as our cities have grown — with collapsing buildings posing one of the largest risks. But why do buildings collapse in an earthquake? And how can it be prevented? Vicki V. May explains the physics of why it is not the sturdiest buildings, but the smartest, that will remain standing.

 Lesson by Vicki V. May, animation by Pew36 Animation Studios.

Earthquake (P and S waves)

An earthquake generates a P wave (fast and longitudinal) and a S wave (slower and transversal).  Because of its greater velocity, the P wave arrives before the S wave.  In this video, the dog senses the P wave 5 seconds before we see the effects of the S wave.