ShakyGround

Seismic source spectra in terms of displacement density[4] can be described in terms of a low pass filter, i. e., with a flat part at low frequencies, an intermediate part where the spectrum starts to decrease, and the high frequency part where we note a steep decay, often proportional f-g, where the spectral roll off [...]

Ground motion estimation for the purpose of seismic hazard and loading analysis may be eventually carried out in some empirical manner or on the basis of theoretical models. The empirical approaches consist essentially of the use of observed relations of strong ground motion parameters derived from various earthquakes zones. In a more refined manner [...]