I am modeling a soil column for effective stress analysis, and the results show that the top 20 ft of the soil deposit is liquefying. I ran the model using a series of short-duration crustal motions and long-duration CSZ motions. The response spectra at the ground surface differ significantly between the two cases the short-period response is highly amplified under the crustal motions, whereas this amplification is not observed under the longer-duration CSZ motions.
Does this behavior seem reasonable? Also, what factors could contribute to stronger amplification in the liquefied layer when the site is subjected to short-duration motions? Here is the plot of amplification ratio for these two input motions.
