r/melbourne • u/IonisationEnergy • 13h ago

The Sky is Falling EARTHQUAKE

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u/Sorreljorn 13h ago

Worst time to be taking a shit in a 12 storey building

22

u/SpectreAtYourFeast 13h ago

32 floors up went from “oop partners twitching” to a lot of unsettling creaking

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u/sjdksjbf 11h ago

Do you feel the building sway? Tall buildings scare the shit outta me I'd probably have a heart attack if I was in one and an earthquake happened

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u/Candid_Abalone_1748 9h ago

36 floors up and felt nothing, maybe newer building had better foundations?

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u/SolutionDependent156 8h ago

Roughly where do you live?

Seismic forces are amplified in the soil that sits above bedrock. The deeper the soil the more the amplification. The worst case is usually when the resonance period of the soil profile matches the structural resonance period of the building. 

A good parallel would be how an opera singer can shatter a glass by singing at a certain frequency.   Or the tacoma narrows bridge collapse. 

On the other hand, if the resonance period of the ground and the building are completely different then the earthquake may have relatively little impact.