Spectral acceleration
Unit for measuring earthquakes
Spectral acceleration (SA) is a unit measured in g (the acceleration due to Earth's gravity, equivalent to g-force) that describes the maximum acceleration in an earthquake on an object, specifically a damped, harmonic oscillator moving in one physical dimension. This can be measured at (or specified for) different oscillation frequencies and with different degrees of damping, although 5% damping is commonly applied. The SA at different frequencies may be plotted to form a response spectrum.
Spectral acceleration, with a value related to the natural frequency of vibration of the building, is used in earthquake engineering and gives a closer approximation to the motion of a building or other structure in an earthquake than the peak ground acceleration value, although there is normally a correlation between [short period] SA and PGA.
Some seismic hazard maps are also produced using spectral acceleration.
Sources and credits
This article is adapted from the Wikipedia article “Spectral acceleration”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Hawaii 1998 0p2s 2p50.png by United States Geological Survey (F. Klein, A. Frankel, C. Mueller, R. Wesson, and P. Okubo), Public domain
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