How do buildings collapse in a downward direction during earthquakes?

Question

Example: [https://youtube.com/shorts/t1nC0AOP_X4?feature=share](https://youtube.com/shorts/t1nC0AOP_X4?feature=share)

I don’t get it. The Physics of it. And also how would one prevent this?

In: 6

Answer 1

Let’s say you got 4 interior walls and 4 exterior walls on each floor. You break one, and now you got a 12% more weight on the remaining ones, and given that there are conditions present that caused one to fail while supporting the normal amount of weight, the remaining ones holding the extra are even more likely to fail. Second one goes, even more weight applied to the remaining ones. Then another, and another, and boom, jet fuel/steel beams and whatnot.