HELP HELP Peace10 (Mechanical) (OP) 30 Apr 14 05:59 Hello Everybody !! I have a duration of earthquake excitation = 11s & I want to know its frequency !! is there any one who know how can i solve this problem ?? Thanks RE: HELP Ron (Structural) 30 Apr 14 07:33 See this link.... http://www.fema.gov/media-library-data/20130726-15... RE: HELP Peace10 (Mechanical) (OP) 30 Apr 14 08:36 Thanks a lot !!