5.0 is a pretty good threshold of perceptibility. Above that, most everyone feels it. Much below, and it depends on circumstances.
5.0 is probably loud enough to hear. Anybody sitting down would probably notice some movement. Something that was about to fall over anyway might just fall over. It will be over before it can do much of anything significant. It's just a little reminder from Mother Nature, a postcard saying 'thinking of you.'