USGS CMG InfoBank: Natural Periods of Structures During Earthquakes

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Comment: 14:21 - 15:21 (01:00)
Source: Annenberg/CPB Resources - Earth Revealed - 9. Earthquakes
Keywords: "Mexico City", earthquake, "natural period", "surface wave"

Our transcription: An example of this type of amplification occurs when a child is pushed on a swing.
A gentle push in time with the swing's natural period sends the swing higher and higher.
In the 1985 Mexican Earthquake, seismic surface wave periods matched the natural periods of Mexico City buildings between 10 and 14 stories high.
Structures in this size range were seriously damaged.

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