Fourier amplitude units,ground motion data

[epornamazian]

when we input ground acceleration in g units,what is the Fourier amp units?
is there any way to calculate the earthquake duration by McCann$Shah(1979)(RMSA)?
Thanks.

[huffte]

Hi epornamazian. As for your first question, I think a forum search on Fourier units will be a good starting place to track down the answer to your query. And regarding the second question, McCann and Shah duration depends on an algorithm which computes the cumulative RMS acceleration of the original accelerogram, its derivative, the cumulative RMS acceleration of the reversed accelerogram, and its derivative. So, I think your best solution to that problem would be to develop your own spreadsheet or program. I wonder if significant duration - either 5-75 or 5-95 - might be a suitable substitute for you. These are frequently cited in the literature. Best of luck epornamazian.