Shaken and woke

I just want to put this out there in case anyone else has been experiencing this or has some explanation.  For the past few months I have awoken to my entire bed shaking and then it stops. At first it was only maybe once a week, but it is happening more frequently now and causing me to pay more attention to it.  In the beginning I kind of blamed my partner, but he does not wake up so I felt that was silly.  Then I thought, well maybe it was some distant earthquake I was just sensitive to for some reason.  The last one was the evening of Feb. 3 so I decided to look to see if there was an earth quake.  I could not find one near me.  Is this happening to anyone else?  Any ideas at all?