concrete aall in between the top heavy alot iron more heavy top i think because when earthquake is shaking then top is heavy and isnt directed by the lighter weight underside it stays in middle while shaking therefot it stabilizes everything under it. Then all under till bottom is lighter concrete the top is more heavy iron and in the concrete all below hill bottom is having a inner iron skeleton and that is poores maybe with liquid molten iron so the iron top is mounted to an iron skeleton with concrete around that untill the bottom and the bottom must be even more heavy then the top so in a rwal heavy shaking all the byilding bends and dont break and therefor no people will gwt hurt the bending is far safer then crushing breaking down or collapsing thanks to the iron skeleton ithe whole building can only bend very safe. A iron skeleton can be drilled ibto any skyscraper without a iron skeleton yet just drill it with a mole kinda robot drill.

Metal skeleton keeps skyscraper standing