I have been trying to recalculate the MW moment magnitude, so I selected the frequency window, then I used the command D (displacement), but the spectrums don't appear, says no response info.
There is a tutorial that you can download to learn how to use it. The file is in PDF format and it's available on the link below.
Download link: http://seisan.info/seisan-tutorial.pdf
Note: You also need a PDF reader that is capable of opening the file. Follow the link to select an application: http://software.informer.com/search/pdf+reader