Properties of Earthquake Ground Motion
Earthquake ground motion time histories are the inputs aseismic design. Ground motion time histories of strong earthquakes are, generally, recoded as accelerograms, i.e. values of ground acceleration as a function of time. Analytical methods are then used to derive the ground motion time histories of velocity and displacement from the accelerogram. The application, Gmth, makes these computations, and also computes the dynamic properties of the earthquake ground motion, e.g. response spectrum, power spectral density, number of zero crossings per second etc. The acceleration time history is made available to the application as an ASCII file with extension .ths, and is to be copied in the applications directory.
Click here for more details on Earthquake
Ground Motion
It
is possible to synthesize an accelerogram, which has certain known
characteristics of ground motion, e.g. peak ground acceleration, power spectral
density, duration of strong motion, shape of the strong motion window function
and, above every thing else, a specified response spectrum. Such synthetic
accelerograms are called Spectrum Compatible Accelerograms, and are very useful
components of Seismic Design. For more details on Spectral compatible
Accelerograms and Power Spectral Density Click here 
This page was updated on 11 January 2011